Diesel for Llittle Boats

[Chimo]

If someone wants to start it im more than happy to contribute some of the ideas we have.

Cheers PB

OK there you go; :P

If one wants to avoid stern drives and big engine boxes above the floor and go diesel; how to do it?

Maybe someone needs to convert a Subaru flat four into a diesel.

Can you run a dry sump with a diesel?

Sticking the engine in the mid ships and running a shaft has some appeal except for running aground which seems to be best done in outboards in the Gold Coast undredged waterways. At what point does a keel become undoable?

Cheers
Chimo

[Noelm]

My son in law has just got a 25' Bertram with a stuffed Volvo diesel in it, he is wondering whether to replace/rebuild it, toss it out and put a pod and outboards on it, and even though it is a tiny 4 cyl diesel motor, the engine box is gigantic, often thought about some sort of flat diesel, the Subaru engine although a flat 4, is still reasonably high from bottom of sump to top of motor, mind you, nothing like a "normal" motor, in something like the Berty, the really deep V makes for a lot of room under the floor, that a flat something would fit into very nicely.

[Smithy]

Why re-invent the wheel? There is a production boat that fits of Chimo's criteria above, is 2.5m wide and trailerable. The 7.7m Reelax Capricorn. I just so happen to have one.

http://i187.photobucket.com/albums/x197/blackfin15/Pic026.jpg

With regard his last sentance above, this boat does have a keel guard. I have been running it up the beach at Bribie without a problem.

http://i187.photobucket.com/albums/x197/blackfin15/Pic023.jpg

On the steering thing, it is just a matter of getting used to it. I am yet to get myself crossed up yet as I am aware of it. I steer good to starboard forward and good to port in reverse. I can kick myself over to port nicely when parking on the port side with the windmell effect of the prop. A thruster would make life a little simpler. The ultimate solution is David Pleysier's Beluga rudder system. You could nearly retro fit it to mine but would be easy to do from new. It is similar to the prop tube type things on trawlers etc. Certainly all the little crab boats up here on the Sunny Coast that are single shaft drive semi displacement things get on ok and they have tighter pens than me. Plenty of plate shaft drive boats getting around at commercial ports like Burnett Heads, Hervey Bay and here at Mooloolaba.

Mine has a prop tube similar to lots of US boats. They do a few similar. The 25' Bertie in Myles' post on the other thread is a ripper but no prop tube. The other boat bought up in that thread is the CJH Sportfisher which is a 26'er with twin diesel Yanmars under the bridgedeck so it leaves a flat cockpit. It was trailerable but extremely exxy for the size with the massive initial purchase price of the two diesels there. Leigh O'Brien of the O'Brien boat building family from Townsville did a similar thing to that 25' Bertie but in a 23' Formula. It was a single shaft diesel with Cummins power and a little tuna tower. It was a little weapon.

http://i187.photobucket.com/albums/x197/blackfin15/Pic027.jpg

The massive thing I have found with mine is the 180 degree fishability. This was pointed out to me by the old owner Peter Stevens and he is 100% right. So far I have only lost one mackerel around the prop. I'd lost a lot more on the Stabi. Pod mounted boats are pains for fishability. I don't like Jeff's transom setup at all in the other thread but he was critisising engine boxes for getting in the way. I reckon by the time they stood behind his bait esky setup then got over the outboard or cleared those boarding platforms you would be stretched. That is critism of all those Portifino transoms and full pod setups as well. My Mclay and Stabi were both full pod setups and a bit of a pain at times. The go for sterndrive diesels is jack shafting them. Plenty of examples of them. The Vasards did it and were centre mount centre cabs, had a pretty good think about a WA Chivers at one stage that was the same and I am sure there have been a few plateys like that. Build an esky box or bait station or whatever over the engine box.

http://i187.photobucket.com/albums/x197/blackfin15/013.jpg

Getting back to my boat, they were probably a bit exxy back then. I think they ranged in price from $90K up. I have seen the tax invoice for mine originally in 2003 for $130K but that was in survey and it was pretty decked out with the cork cockpit and water tanks etc. That was probably a fair bit back then but talking to George from Reelax he could probably do a new one for the same sort of money or $150K or so. The biggest cost is the diesel at $30-35K. Now if 685 Cruise Crafts etc. are going for that $130K sort of money and knowing what my boat can do into a headsea due to its weight it would be an interesting decision for someone in that end of the market. That is without trailer on the Reelax but the CC would be with trailer. Certainly if you lived on the water and wanted something to live on the water without an air berth or Sea pen or whatever, diesel shaft drive is the go. It would save you $20K on the initial purchase price of an air berth or similar. For survey the diesel is highly regarded from the safety point of view. The low flash point of the diesel and on the old school diesels, so long as you keep the fuel and air up to them they should keep running as there is no electrical system needed. It is a bit different now with all the computer control stuff on them. If you rack hours the diesels are the go. I am at 7,400 hours. Doubt if an outboard would get anything approaching that.

So short of someone marinizing a flat motor the options are big bickies like the CJH Sportfisher, boats like the Albermarles or Carolina Classics, jack shafting anything or a big platey or a diesel shaft drive like the little Pleysier or the Reelax or something custom.

[Noelm]

Have a look at the size of the engine box in the back of the Bertram, it is almost wall to wall, and it is a pissant 120HP 4 cylinder.

[PB]

The biggest problem with most of the ones around is they are to big and heavy to tow and shaft drives can be a pain at some ramps if you do a lot of towing, if it was going to be moored i would bother with a boat under 35'

I think the jack shaft to a leg is the way to go.
We tried pushing the motor under the bridge sole but it played with the trim to much and the hull shape would have been more of a displacement hull rather than a planing hull, not what where looking for.

Ive been on the Carolina Classic 25, awesome bit of gear but its huge on a trailer and pushing the 4.5t. the key is to get a mid mounted diesel around the 7.5m mark that can be towed by a LandCruiser.

[myusernam]

i like the look of these.
On a trailer so sterndrive doesn't matter (better) but with jackshaft to the motor midmounted (think i have seen the engine box further forward than these examples. 315hp yanmar. sweet
http://www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=12863151
http://www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=12600073

[chris69]

Get a old council bus there motors are volvo but a flat turbo 6cylinder

[gofishin]

Twin 470s were pretty standard in the B25's Noel from memory, so that is where the box size comes from.

Jack shafts and leg would move the box forward, but would still be there. As suggested a sports bridge layout would get around the box, but only the yanks still build them it seems.

Other than a 23/24 Searay, which was a real rock & roll boat, the only 23-25 boats that I put diesel S/D's in (with a flat cockpit) were 23/24 Fjords. Good hull but a hell of a 'coaming' to make up for the high floor.

Marcel (CCC) was making jack shaft 4 cyl volvo DP's (130hp) in ~20 ft boats around 25 yrs ago.

Diesels have come a long way in that time, much lighter with more power, but I would say it is the cost which has held then back.

I love the handling benefits of a low slung Duoprop diesel (compared to O/B), but in all our shallow country it's nice to get out of shallow/tricky situations with an O/B. Universals and boots/seals don't (didn't) like that -maybe current ones are OK? That's why I have an O/B. :)
Cheers
Brendon

[Alchemy]

I like the set up of this Cairns Custom Craft, though unsure of how stable it would be at rest as the deck looks to be very high.

http://www.cairnscustomcraft.com/8000seriesgallery.htm

[ashleyhj74]

I'd love to get a diesel for my Vasard 7.5, its mid-mount with a 350 chev/mercruiser, jack-shafted to stern drive. But alas funds dont allow for that just yet.

[peterbo3]

If you want a lower profile deckbox over your diesel you are going to need a wider boat to give you more room under deck, which should not be a huge issue with the relaxation of overwidth trailer regulations.
Combined with a prop tunnel & keel as shown on Rob's boat, you can run a shaft system on a small boat. The tunnel shown below is on a much larger boat & is big to accomodate the propellor.
Given a set of drawings done by a Naval Architect, a good alloy builder will fix you up. But it will not be cheap.
However, I have spent a lot of time on Rob's boat ::)::) & his engine box is great. It is a simple system & it is 100% functional. You can access the filters, belts, heat exchanger anodes & all the other things that need to be got at from the deck.


http://i100.photobucket.com/albums/m31/peterbo3/PropTunnel.jpg

[The Woo]

George Sant built the Excaliber 740 in the 80's. It was a great sea boat, and wouldn't ya know, was typically fitted with a mid mounted deisel, jack shaft, and leg. The engine box served as a game chair base or rod holder, tackle station.
Here's one for sale, but it's been terribly altered along the way ending up somewhat useless with the addition of a second targa arch;
http://www.tradingpost.com.au/Boats/Power-Boats/Power-Boats/AdNumber=TP005310256

And Chime, Subaru already sells their flat fours as a diesel in their cars.... so get marinising mate :p
And yes, you can fit a dry sump to ANY engine.

Noelm, the 25 Bert pictured is evidently using the standard issue twin Mercruiser engine box. Bloody great waste of space that.

Does anyone remember Peter Webster's Star 7.4m tin boat? If memory serves me right it was also mid mounted/jack shaft/volvo leg equiped.
I really don't know what we don't see more of this (Vazard included) jack shaft layout. I suspect cost is the main culprit.

[myusernam]

http://www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=12600073
anyone been in these? Any reports? I thought the price is not out there, although for that money I could think of other things...

[Smithy]

Like those links to the Witchcrafts. Those SA guys build some good boats - think Claytons, Theodores, Northbanks etc. that we don't see up here in SEQ. Very practical commercial boats with hard tops.

[OPTI]

what the visability like on your boat smithy ?those windows look dark

[Stuart]

Yeh, should have called darth vadar.

[Midnight]

I've got Limo tint on my Bertram and it is really good. You can't see in at all, and it blocks 72% of the heat. But standing inside looking out, it is just like having sunglasses on, not too dark at all.

I imagine on Smithys boat, with an open bulkhead hardtop, it would be even lighter than mine looking out.

Cheers,
Myles

[ozlongboarder]

Smithy, what motor do you have? Whats your cruise and max speed and fuel burn at both?

www.25bertram.com for plenty of repowered 25s.

[wirlybird]

http://www.mercurymarine.com/engines/diesel/tdi/

I have been looking at these

Diesel 350 hp = 368 KG

Yamamha 350 HP outboard petrol = 364KG

Getting there

[ScottB]

Hi Whirlybird,

Have you had any prices on that 4.2L version (with or without leg?)?


Thanks

Scott

[PB]

If you want a lower profile deckbox over your diesel you are going to need a wider boat to give you more room under deck, which should not be a huge issue with the relaxation of overwidth trailer regulations.
Combined with a prop tunnel & keel as shown on Rob's boat, you can run a shaft system on a small boat. The tunnel shown below is on a much larger boat & is big to accomodate the propellor.
Given a set of drawings done by a Naval Architect, a good alloy builder will fix you up. But it will not be cheap.
However, I have spent a lot of time on Rob's boat ::)::) & his engine box is great. It is a simple system & it is 100% functional. You can access the filters, belts, heat exchanger anodes & all the other things that need to be got at from the deck.


http://i100.photobucket.com/albums/m31/peterbo3/PropTunnel.jpg

We have also looked at widening the beam to get extra room but it only makes to hull sit higher in the water as its adds buoyancy, the dead rise would have to be reduced and therefor loosing the extra room. where pretty close to getting a design sorted that will tick the boxes.

[Midnight]

G'day,
It all depends on what you want from the boat. Speed, distance to travel, bottom basher, troller?

The Capricorn really impressed me, the only negative for me was the lack of bunks. The little Arvors are great too, but if you need to run 50nm, the 16kt cruise speed will probably rule it out. Steber Persuader are a great option too.

If you look at all of the above boats, you will be able to get ideas to build you own.

Personally I would be going for a mid mount, v-drive shaft drive, with or without a prop tunnel. There is really no problem with them going on a trailer, once the trailer is well designed. Otherwise, jack shaft to a stern drive is the go.

I think you have to start with a clear plan of what the boat will be used for, and start from there. This will make it a different boat for each person pretty well, but that is the whole point of a bespoke boat.

Cheers,
Myles

[Smithy]

My Yanmar is the 4lha-stp 230hp 4 cyl at 3.45 litres capactiy. The current version is a 240hp motor. Would have to look up how much it weighs. It is connected to a ZF gearbox running auto transmission fluid. If I was to repower I would look at all the options. Captain Rednut reckons the Hyundai Seasal would be a good choice for me. I think they do a 265hp version. I would love the ability to go to whatever gearbox and have a trolling valve. The Yanmar comes with that ZF box and that is it. One running the same oil as the main engine would be good like most boat gearboxes. Electric Morse controls or similar would be nice to a Twin Disk box. The VW based V6 twin turbos would be good. Cummins-Mercruiser were doing one of those at 285hp I think. Sounds like they just had a lovers tiff though and Mercruiser is out on its own. You'd also have the Steyr and the Iveco motor to throw into the mix but there is a lot to be said for the older an proven technology of the Yanmar compared to these high revving ticking time bombed to the ass engines. I get about 27-29 litres an hour for 2800rpm for say 18knots. Hard to know. I don't have floscan which would be good and with 460-500 litres of fuel tank, I never keep them 100% full as I would be carrying around heaps of weight. I usually only fill my port tank as my prop torque really lays me over to starboard. Eventually my tanks even up due to gravity and also because I send my return line to both. I have the ability to draw off either tank or return to either. All I can go off is the 415 litre trip I did from 1770-Mooloolaba when I bought it down which was 12 and a bit hours for 29 litres an hour with a dirty bum. I have just repitched my prop to get it to spin to its 3300rpm a bit easier. I was a bit over propped for the weight I push around. Maximum continuous rpm for that motor is 3100. I probably top out at 23knots now. If I run at 2950-3000rpm I get my 20knots. That is running a 21"x21" prop. It originally spun a 21"x23" prop.

On the tint, I am not happy with it. I am not sure why Mick the old owner went with that. It is on my program to change. Baby steps though. It isn't too bad as Myles said, being open bulkhead it is just like having sunnies on. At night I only run with the GPS and engine gauges on with a beanie or hat over the compass and I pick up tinnies and stuff at anchor ok. As soon as I can afford it I am going to side clears. The hard top is great at the moment in winter and for water proofness. I still put the nose through short sharp ones at troll speed etc. so a bit rolls up the windscreen. Originally this boat had a perspex windscreen to clear infill setup. The 2nd Capricorn was the ultimate. It had a full glass windscreen with opening panels etc. to infill clears.

[PB]

This is the motor we are looking at using http://www.mercurymarine.com/engines/diesel/tdi/?model=1 its a VW engine jack shaft to a Bravo 3 Leg.

Smithy are they still building any Capricorn's?

[wirlybird]

Hi Whirlybird,

Have you had any prices on that 4.2L version (with or without leg?)?


Thanks

Scott

They were saying mid 30k but as typical salesmen didnt want me using my TRS leg and couldnt agree on a price untill they see my boat so i said "its in my driveway come and have a look" they gave up on the idea after that. No skin off my nose 35k back in my pocket and off i go.

[Smithy]

PB,

they just finished the third one. It was Ray's personal one for use up at Pt Hinchinbrook. They made it into a centre console with a small cuddy at the front like some of the big US centre consoles. As far as I know George from Reelax was keeping Steve Peake on to do fibreglassing for him and to do Steve's Skippercraft Archer 650s. Steve is Clayton Peake's brother from SA. The moulds are all there at the back of Voyager Cats shed at Woongoolba. The guy from Legacy Boats was involved in the build as well. Rays had the 200hp Yanmar installed instead of the 240 to the keep the cost down a bit and he will only be playing in Hinchinbrook passage.

[ozlongboarder]

Interesting numbers. My 25 Bertram runabout with a single 280hp Volvo V8 with duoprop. does approx 32lts/hr/3000rpm at 20knots.

In order of preference I would like a diesel shaft, then outboard then a stern drive for a boat that is permanently moored. Dealing with barnacle growth on a stern drive gets old real quick.

[deckie]

Was on a small Arvor (215 maybe ??) about 18mths ago and struck me how the engine box was hardly even noticeable and pretty low. Obviously no rocket ship and had a small Cummins i think..maybe about 110-125hp. No idea how they go in open water but nice deck layout.
Dont know if anyone does same for bigger donks...no idea what they could cram into that space but looked tiny and low even for that type of rig.
Clayton Gallant around 7m would be perfect for xmas, but the big diesel sterndrive looks like it takes up half the cockpit and as high as gunwhales.

[myusernam]

there seem to be a lot of commercial 7m shark cats with single 200hp volvos. Why? stats I have found is 15Lph at 15 knots which ticks my 1nm per litre box but surley at that speed the cat hull is actually a disadvantage and it woud ride like pus? Don't you need speed for the tunnel to work? Most workingboats are highly powered, not the other way around. I would have thought mid 20's would be the aim for cruising speed in a cat. Also I thought planing hull cats weren't great at carrying massive loads but these spanner cats must be? Is it becaue they are'nt trying to go fast?

[myusernam]

http://www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=8492758
check this out

[Smithy]

Had some mates fish that jack shafted platey at Port Stephens at the start of the year and they didn't like it. One of those bangy plateys.

You're onto something with those diesel cats. There are certainly a couple of them working out of here used by the spanner crab boys. When you look in the fuel book at the diesel dock where we are getting our diesel they are all only using 60-70 litres a day. I'd say the shear weight of those old Shark cat hulls will help them immensely. The other option is something like a 7.2KC with twin Yanmar diesels or similar. There are a couple running around. Very worthwhile on the 2nd hand market but would be exxy to build new from scratch. Probably over the $200K mark. There is a 7.2m in our club called Reel Capture. It came up in a previous thread. Jeffo mentioned it had more a displacement boat feel about it. Maybe the big cats work well like that and it is only us Aussies who want to power them up with big outboard horsepower and go fast on the top. Roger B on here ran a semi displacement cat charter boat in England that was very successful with moderate horsepower Perkins diesels. There is Craig Pollermounter the Canterbury Bulldogs footballer's Kevlacat that pops up from time to time on Boatpoint which is a sistership to Reel Capture. Reel Capture was Fred Temminck the old Kevlacat owners personal boat so you know it was built well and pretty much to survey standard. There was an 8m KC with a lock up cab for sale recently with twin Yanmars which was on a trailer in NQ that was sub $100K.

[myusernam]

i rememner a guy on here claiming he had a 7m noosa cat long cabin with twin 4cyl vovlo diesels that gruised at 22 - 24knots with the same fuel burn combined. If so pretty good but sounds a bit too good to be true..

[PB]

The biggest problem with boat manufacturers changing engine configurations is they don't change anything else and 9 times out of 10 one configuration wont work as good as the other and sometimes its the opposite but this only means the hull wasn't designed right in the first place. where starting from scratch for our new mid mount inboard as we believe its the only way it should be done. yes it would be a hell of alot cheaper to just modify out current outboard version but the calculations just don't add up.

[dugggy]

821988219982200
These are pics of the setup I inherited.The Cummins sits very low and the jackshaft leaves the transom clear.Hopefully the shear weight of it so low will help with stability at rest too.Gladly swap the old Cummins for a new V6 Hyundai diesel though,600kg lighter and 50% more HP.
Doug

[Smithy]

I agree. At the end of the day there is only so much calarific value of energy in each litre of whatever fuel and if it has to push X weight at Y speed, there is only so much that can be done for the mechanical efficiency of the motor and the slipperyness of the hull through the water to give you the fuel burn. Some figures you see seem to defy the laws of physics. Unless you start with a full tank and finish with a full tank or have floscan or similar you are really just guessing. I have been told by the skipper of the new charter boat at Noosa he gets his 20l/h for his 20knots on a
9.9m ally boat out of Noosaville at the moment its got a 330 Volvo with a duoprop it burns 20per hour at 27rpm at 21knots with 14pob we do sunshine out to massounds out to chardons back sunshine home 23lt of diesel for the day. I'd like to be getting that with my 3.5T, 25' boat with a 230hp let alone a 30' boat with a 330hp.

[cormorant]

Must be a buyers market out there as there is a fair few reasonablly maintained boats out there for sale. Lots cheaper to buy them than build em.


Just did a search for Diesel shaft cat . There is a has been built few sailfish ones made, markam and devilcats but you are getting away from anything you can trailer easily. Here is a couple with underfloor set outs .

http://www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=12113944

http://www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=12301305

http://www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=12184812

http://www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=12113934

Never heard of these- leg

http://www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=11301850

Guess they didn't pay the storage bill? Bargain or trouble?
http://www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=12074558


Not a diesel but crap this seems cheap

http://www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=12654755

[Midnight]

I agree Smithy, some of the figures you see quoted shows that the owner has no idea how much fuel their boat really burns. Basically, you can't get around 20L/hr per 100hp used.

My Bertram 25 with a 200hp Volvo Turbo diesel was 30L/hr at 18kts (3.5 tonnes deep v). I know that because I ran the boat from Scarborough to Mackay at 18kts the whole way, and went from full tank to full tank at each refuel. I used to average around 15L/hr start up to shut down for a 15hr day, out to the shelf and back.
30L/hr is close enough to 150hp being used to push that boat to 18kts.

My Bertram 33 is 80L/hr at 18kts On the Floscans (11tonnes, deep v). 40L/hr or 200hp being used from each engine. For the season last year, I did just under 300hrs for an average "block hour" fuel burn of just under 22L/hr. but I do a lot of trolling and putting around the Hawkesbury at 7kts when we go family boating.

There are very few mechanical diesel engines that will make more than 100hp/19-20L burnt, and it all has to do with the calorific value as Smithy mentioned earlier. We used the same formula for water pumps and tractors on the farm, always works.



Cheers,
Myles

[Smithy]

Cormorant,

some good links there. The two KCs and the Broadbill are certainly good buying for the right person. Even the Shark Cats if you don't want to go too fast.

[wirlybird]

i have seen an ex waterways Broadbill with 225 hondas sell for 26 grand i dont think its well priced as far as the market is conserned. but its tough out there ATM

[chop duster]

bit off OP subject but:

While researching our TAMD70D's the best info I come accross regarding fuel consumption was the attached graphs denoting grams of fuel used/horsepower @ a given RPM, giving you the most fuel efficient points in the RPM range...

Calc's below:

1 litre of fuel is 850 grams.

@ 1600rpm the engine uses 162grams of fuel per horse power.
@1600rpm puts out about 195hp
Therefore, 195 x 162 = 31590grams of fuel.
31590 divided by 850 = 37 litres / h

@ 1825rpm the engine uses 157grams of fuel per horse power.
@1825rpm puts out about 235hp
Therefore, 235 x 157 = 36895grams of fuel.
36895 divided by 850 = 43 litres / h

@ 1900rpm the engine uses 157grams of fuel per horse power.
@1900rpm puts out about 240hp
Therefore, 240 x 157 = 337680grams of fuel.
37680 divided by 850 = 44.3 litres / h

@ 2000rpm the engine uses 160grams of fuel per horse power.
@ 2000rpm puts out about 245hp
Therefore, 245 x 160 = 39200grams of fuel.
3920 divided by 850 = 46 litres / h

@ 2100rpm the engine uses 162grams of fuel per horse power.
@ 2100rpm puts out about 251hp
Therefore, 251 x 162 = 40662grams of fuel.
40662 divided by 850 = 47.8 litres / h

@ 2500rpm the engine uses 170grams of fuel per horse power.
@ 2500rpm puts out about 270hp
Therefore, 270 x 170 = 45900grams of fuel.
45900 divided by 850= 54litres / h

The least amount of grams required to make a horsepower is the most efficient rpm.
Boat planning speeds etc.. obviously throw these calc's ut of wack in the real world, although apart from a flowscan these are the next best thing....

[cormorant]

Please don't upset our shark cat owners - they are just uninspiring at those speeds but as a workboat and with the diesel rebate etc they worked out OK.

Chop Duster it is so good with diesels that you can get the full curve and know you are running them correctly loaded as you get a good life. You can see exactly where your ecconomy and designed longevity is especially with the commercial derated versions. Just have to buy the right size and style at the beginning for the performance your hull requires and you can use in 80% of conditions. Yep I've run outboards and 40kn plus plus performance and had a few wonderfull days a year when it is glassed out but 90% of the time they are underutilised. Had the same with underpowered and wrung the neck ot of smaller ones as well and got away with it on 2 strokes as they eat it but not with a new 4stroke. Non of the bullcrap outboard advertising with the commercial rated diesels..

I am still waiting on the turbo diesel outboards ( apart from the avgas etecs) and the podded diesel V- drives to get in the market as they priced right will be so good since there is so many pleasure boats in the USA now designed for very heavy twin and triple set ups and I would love a diesel version. Won't go as fast but won't burn the bum out of my wallet in running costs. I just hate sticking my head in the bilge maintaining a diesel.
http://www.megoutboards.com/

Here is one you'll like Smithy. Need a mini me version and not sure propping it for lighter weight would get huge performance improvement. Probably a bit off track as a small boat but I used to be surprised just how good these were loaded up in average weather and bouncing them off a dock won't hurt em. Windage on he cabin so far forward for drifting etc is a issue. With all these new marine parks and costs of fishing there will be a lot of great old hulls about in teh next few years. I see the upgrading of teh VMR fleets and standardisation of vessels is allowing some very well appointed boats on the market as well.

http://www.gumtree.com.au/s-ad/sorell/boats-jet-skis/clayton-fishing-crabber-9-75-metres/100412669

Now this would be good to run around in for a while - comes with spares and what a great delivery home trip!!!! Nearly worth tossing in with 4 guys and having the adventure of a lifetime bringing her home. If she was a shaft drive I'd be tempted.

http://www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=12898300

Smithy

Here is a bloke local to you QLD rs- your kicker motor instead of a troll valve!! Never seen one of these

http://www.klaxondieseloutboards.com/

[myusernam]

$54000 rebuild...WTF?! surely a new motor is cheaper?

[chop duster]

Bit of food for thought --
The 2 TAMD70D volvos (2x270hp) combined chew 108 L/H to produce 540hp.
The 250 Merc Verado on our center console chews 110 L/H to produce 250hp. But it is exactly 1/3 the weight and pushing a bit over a ton to 45 knots...

[cormorant]

$54000 rebuild...WTF?! surely a new motor is cheaper?


And their lies the reason there isn't commercial diesel motors in small boats - it is bloody unaffordable to justify the costs unless you spread them over a lot of hours of commercial use with capital cost tax deductions and fuel rebates.

It used to be a old govt department strategy to repower vessels just before sale as they could bulk buy without tax etc new motors and fit them up and sell them at a profit retail attached to a boat and some charity not for profits did the same as they had a double bonus if the engine supplier alowed the "donation"of the difference between wholesale and retail and the supplier got a tax deduction. Most of these loopholes have been stopped. Some of the supply contracts had "uptime" clauses so if a replacement block or it's repair wasn't avaliable etc etc there are large daily penalty's for a vessel not being avaliable and in service within a few days. A 2 week delay and paying a suitable standby vessel charge of thousands a day often meant vessels were kept in very very good nick and manufacturers left spare motors / powerheads ready to go as it was cheaper than the penalty clauses.

Probably pulled out to rebuild and they decided to repower and rebuilt the other one afterwards. Problem with twins is that you need them both the same so if you upgrade one you do both in teh exact model and spec.

Simply the updated motors with lower fuel use , lower downtime, lower maintainance and fresh legs may have made it ecconomic to repower.

No idea what the story up there is but by the time you have sold off the motors you have a very capable boat at a prety good price.

So how much is a new one delivered Darwin I hear you ask??? I don't know but someone here will.

[Midnight]

Chop Duster,
Your best hp/gram or fuel burnt there probably coincides with the peak torque RPM.

I have always worked on the theory of operating at the peak torque rpm, or just above it, for the cruise speed, to gain the greatest efficiency and have the engine operating at its most comfortable load and rpm.

If you can spec the engines so that this occurs in a new build or repower case, or you are happy with the cruise speed for the hull at the peak torque revs, in an existing set up, then you are absolutely onto a winner.

Thanks for the numbers too, they don't lie. And in all cases there, except WOT which is normally slightly less efficient, you are running pretty well 19L/hr per 100hp.

Cheers,
Myles

[chop duster]

Myles,
Unfortunately the 18-1900rpm is just off planning speed.
15 knots cruise @ around 2100rpm has been looking the best.
You appear to know a bit about diesels so what are your thoughts on:
Have a couple of Cummins 6BTA 370hp's sitting in the shed with only 700 hrs on them.
Fuel Curves etc.. attached.
What are you thoughts around the actual fuel consumption figures one could expect from the cummins as opposed to the volvo figures I have given above.? Im'm thinking the HP/gram ratio will be similar.
P.S - I have my head around the need for tweaking props etc...

[Midnight]

G'day Chop
The 6BTA's are a great engine, and it is what I will repower my Berty with when the time comes.

The big advantage is the nice flat torque curve of the Cummins. It makes more torque at 1600rpm than your current 70 series Volvo makes at peak torque.

At your cruise revs, assuming you can use the existing gear boxes (I know MG506 is ok at 320hp, the 370 Cummins might be touch and go), you will make over 100ft/lbs more torque with the Cummins and significantly more HP. You will be able to swing a lot more pitch, as long as your existing shaft size can handle it.

You are currently using about 500hp to do 15kts, that really won't change a lot, but instead of using 500 of 540 available HP and running at around 93% load, you can run 500 of 740 available HP, at a load factor of 68% for the same performance. A much better scenario for long engine life.
You will probably do even better, as the Cummins will be a bit lighter.

Fuel burn will be directly related to the HP extracted, so if you stick to 15kts, you can expect pretty much the same burn you have now.

The problem with the burns at certain RPM's on the charts they publish, is it depends on the load they use in the "propeller curve". If you use the 19L/100hp you won't be far off.

What type of hull do you have? What speed is the hull really happy at?

I know my Bertram hates dragging its bum at the 18kts I get around at, once I gets over 21kts it really comes alive. The wake flattens out, the ride is miles better and it is generally just a nicer boat to be in. My problem is I don't have the HP to cruise there.

Basically, if you have the Cummins there and the extra coin to do the repower (may need a change in gears, shafts and definitely props), I would do it for sure.
The difference in spare parts price alone would have me do it haha Volvo make nice engines, but they are rapists when it comes to buying spares.

Decisions decisions :)

Cheers,
Myles

[The Woo]

Interesting reading. We're currently undergoing what you guys are talling about. Upgrading the old girl from a pair of 210hp 6BT's to 370hp 6BTA's. It'll be very interesting to see the burn difference. I suspect she'll be a much "nicer" boat with some horsepower under her skirt, as the hull is one that likes to run "fast".
We did briefly consider Yanmar's 6LY3, 5.8 litre engine @ 380hp, but despite it being low, it's longer than the Cummins. That, compounded by the boat's layout being more suitable to Cummins servicability, led us to buy a pair of "remans" from the factory. As you guys would likely know the "remans" are actually new, but the fuel pumps are removed/replaced after the engines are manufacturer and fitted with a "remanufactured" plate. A nice way of getting around emmission laws etc for those of us who want to avoid electronic engines for as long as we can.

Back to smaller, tralierable boats..... Anyone have any experience with the new 4cylinder or V6 Hyundai marine diesels? They're SUV based products, and the specs are quite interesting for their weight. I would have thought they'd be a nice little setup (they're really quite compact!) for a 6-7 metre trailerboat with a pocket shaft and bow thruster. Not having to fish around outboards is so nice!

[Midnight]

Yep, the factory "remans" are the go! Good luck with it Woo, I'm sure it will be like a new boat! What hull, if I may ask?

The Hyundais look good. The hang on parts are all pretty easy to get at, and the base engine is an absolute class leader. Time will tell how good the marinization is.
They are offering very good value for money over their competitors at the moment, and their commitment to making it work seems pretty keen. I would give one a go if I was in the market.

Cheers

[ScottB]

Hi Midnight,

Putting 2 and two together, I would suggest that you check here http://www.thehulltruth.com/boating-forum/412375-father-sons-love-their-boat-refit.html for The Woo's project. I would say it is going to be mighty impressive when finished!

BTW Just wanted to say to all that this is great thread. Very informative!

Scott

[The Woo]

Far out, you nailed me to the wall in one foul swoop! Nice work Scott, and thank you sir! :)

And yes, Midnight, I had a really good chat with the fellas from Hyundai running the stand at last year's show, mainly asking if they had any larger high speed stuff forthcoming (due dilligence prior to committing to Cummins). As you say, the packaging looks good, the performance sure seems to be there, the weightr isn't, and yep, time will tell to see how well the alloys last etc. I really do wish them well, good competition is needed in that end of the market!

Oh, you asked what hull we have. 33' O'Brien flybridge.

[Midnight]

Thanks for the link Scott, I will have to sit down and read all 5 pages at some point!

Good luck with the project Ben, as you said, well worth the effort, and she will be a dream at 23-24kt cruise :)

I plan to do a similar "mega refit" to my B33 someday. It is a great hull and the layout suits me well as a compromise between fishing boat and family cruiser.

Cheers,
Myles

[Smithy]

On the 370s, I used to fish on a boat with 2x370 electronic Ivecos (the new 370-400 block) that had fuel flow. At a 20knot cruise it was burning 35litres/hr/side. I'd hate to think you were up in the 100/hr range. To me that would be what the mid range 450hp sort of motors would be doing. The 51' Riv I worked on with 2x1,000hp Mtus burnt 125-129litres an hour a side for its 20knots but it would do 230litres an hour a side at WOT.

Woo and Myles,

Jimmy is a Seasal dealer now. Dunno if he has had the opportunity to fit one yet. Certainly a #1 contender if I ever repower.

[The Woo]

Well if Jimmy's a dealer best we put our collective thinking caps on and come up with a boat for him to showcase a nice little V6 with!

[Midnight]

Hull shape makes a huge difference in HP required and in turn fuel burn. The deep v's need big HP to keep em going, especially if they are heavy, but some of the other designs that are flatter in the bum don't quite need the same grunt.

Viking 2(46ft deeeeep v) burns 162L/hr combined at 23kts with the 660hp QSM11's in it. I think from memory the Viking is still at 145L/hr at 20-21kts. Only 14L/hr at 8 kits though :)

Most of the guys in the USA, running 330 6BTA's in the same hull as mine are burning around 80L/hr at 21kts, however the majority of them run around at 24 and just burn the extra gas.
When they go from the Cats like mine to the Cummins, the boat loses over 500kg in weight! Helps a lot with the deep v getting out of the hole.

Sorry to go so far off the original thread purpose, I will shut up now haha

But yeah, let's design a 7m, deep v platey, with a jack shafted V6 Hyundai in it, to a Bravo 3 duo-prop leg. Will be a cracking trailer boat for dudes who do a lot of trolling.

Cheers,
Myles

[chop duster]

The woo, I was looking for your thread on the hull truth the other day but couldn't find it. Small world huh?...

Myles, the rig is an old 85/86 44 riviera, not many around. Think there was only 14 or so made. 14500kg dry, 4.65m beam, she is a bloody big 44 footer.
Was available for a good price, and having the cummins sitting there we couldn't say no. She tops out at about 17 knots, this speed I feel would be a good and achievable cruise with the cummins. Perfect world we would step up to the c series 450's but we will make do with what we have available.
The cummins have twin disc boxes 2:1 attached so will suit our current props (with a little trimming) and shafts as confirmed by the local prop god 'rosco'.
Your thoughts basically mirror mine. Only thing holding us up is funds and time.

We will more than likely just run the ovlovs for another year or so if they hold out that long, and sell them as parts when the time comes.

[The Woo]

Yep, a jack shafted Bravo drive with a "veranda" cockpit extension out over the drive so you could theoretically drop a line directly from the transom and not touch the drive unit.
A recess under the transom live well would allow full trim up of the Bravo.
Weight low and centred brings naturally good trim and ride, without excessive downward drive trim or tab use.
Great, now I'll be dreaming about trailerable mid mounted diesel boats! haha

[The Woo]

The woo, I was looking for your thread on the hull truth the other day but couldn't find it. Small world huh?...

Myles, the rig is an old 85/86 44 riviera, not many around. Think there was only 14 or so made. 14500kg dry, 4.65m beam, she is a bloody big 44 footer.
Was available for a good price, and having the cummins sitting there we couldn't say no. She tops out at about 17 knots, this speed I feel would be a good and achievable cruise with the cummins. Perfect world we would step up to the c series 450's but we will make do with what we have available.
The cummins have twin disc boxes 2:1 attached so will suit our current props (with a little trimming) and shafts as confirmed by the local prop god 'rosco'.
Your thoughts basically mirror mine. Only thing holding us up is funds and time.

We will more than likely just run the ovlovs for another year or so if they hold out that long, and sell them as parts when the time comes.


Small world indeed, nice to meet you all :)

The 44's were a rare boat for sure, they fairly quickly bacame the 46, but I'm unsure if there was actually any moulding changed or if BBC realised what a bloody big 44 he'd built and thought, "nah, that's a 46 all day!".

It sounds like you've got yourself an interesting time ahead Chop Duster (love the 24 Mustang avatar, I remember the orioginal advertisement and my mate Noah fished one pretty hard for years).
You might be suprised just how long those 70 series hold on, they actually weren't a bad donk if the coolers etc were services properly.

[Midnight]

Good luck Chop,
Nice to have the Cummins up your sleeve anyway. The Volvos will part out at a good price, as some parts are no longer being held by Volvo, and the ones that are require a second mortgage! :)
Cheers,
Myles

[chop duster]

Funny you should say that. The aluminium heat exchanger housing is a joke, and apparently a well documented problem. We replaced the port cooler with a retrofitted cooler of the cummins (tube type heat exchanger) a couple of months ago, this works a bloody treat. We are currently in the process of doing the same to the starboard motor. I'm loving the simplicity of the cummins, availability of parts and about 200kg lighter for an extra 100hp...

[The Woo]

Yep absolutely. The base Ovlov engine is quite sturdy if they don't get hot, but as you say, their alloy housing heat exchanges are a complete joke. it doesn't take long for salt to start mixing with fresh!
KEEP IN MIND, the aftercooler on B and C series Cummins are better, but only just. Definately pull them apart, clean, re-"o"ring, and reassemble while greasing liberally with a high quality and sticky marine grease. It really is one of the very few weak points to these engines (along with the laughable raw water pump situation from a longevity and servicability viewpoint, quite easily remedied if you act Prior to install).

[No Fear]

Interesting thread all. Some well priced boats in amongst them as well.
Not that I am the most mechanical minded person in the world, but I am running a 200hp volvo diesel in my 7m cat. My cruising speed is pretty well right on 20knots and around the 3000 rev mark - I could ring its neck a bit more and get 22-23 knots out of it but its an older motor (1999) and having been sitting around for a few years, trying to look after it a bit.
Certainly I would love another 5 knots on the speed but having now been on a few trips across the bay in sloppy 1m seas, 20knots is plenty. The boat handles basically the same in those conditions as when it is a millpond.
I havent exactly worked out fuel figures but I am estimating around 30-35 l/h at cruising speed. Trolling for 8 hours doesnt even move the fuel gauge so like you smithy, would love a fuel flow gauge.
I too thought 200hp would be a bit underpowered to push such a heavy boat. Having been in an outboard powered cat, that certainly are completely different boats. The diesel just seems to punch through anything but the big difference is the duo prop. Getting on the plane is nothing and the torque is unreal. Spot82 has nearly thrown me out of the back of the boat a few times changing spots and I have nearly put myself through the windscreen putting it in reverse while docking it.
As I said, would love a bit more speed but I like the way the boat handles. For the money that I forked out for it, I wouldnt have got a new 5m boat let alone anything bigger.
This engine will hopefully get me through 3-4 years and will decide if a repower is the best option. Would love to fit in twin diesels but a 315 is more likely.....
Any yeah - leave the shark cat owners alone!!!

[Midnight]

Chop,
I went from Volvo to Cat, and the difference in price and availability of parts has been amazing. It is so nice being able to order ANY part from Westrac (or the USA) and not being terrified of the price. The Cummins are the same. Millions of them in service in many and varied applications, truck, industrial, marine.

Woo, did you get rid of the Sherwood raw water pumps? Go for the Seamax pumps? Glad to hear you are onto the aftercooler program. The QSB's are no better. A mate of mine just had an aftercooler fail, assembled dry in the factory and never previously be apart.

No Fear,
I think it is the torque and the efficiency of the duo-prop that gives the performance with a comparatively low 200hp. The torque you are making at 3000rpm will be oodles more than a pair of outboards making the same 150 odd HP. Torque is the key when you are trying to turn something.
Your Volvo will live a long and happy life at 3000rpm, so long as you can make a minimum of 3800rpm fully loaded, and you keep the coolers well serviced.

Cheers,
Myles

[The Woo]

No Myles, left the Sherwoods where they are as they will last two years at least. Then, just prior to the warranty running out, they'll fail, and we'll get another two years before changing to the SeaMax pumps. Would love to do them now, but the refit has been, shall we say, somewhat financially draining.

Aftercoolers, yep, done. At Least they're coated internally these days with what seems a pretty high density paint, should slow down the corrosion a few more years.

Before;
http://i139.photobucket.com/albums/q301/bennythewoo/after-BEFORE.jpg

And after;
http://i139.photobucket.com/albums/q301/bennythewoo/aftercooler-AFTER.jpg

Milled up some 5/8" spacers too for the front left engine mount, so you can at least get the raw pumps off without jacking the engine and removing the mount! Crazy shit Mr Cummins... (Having said that, was never a problem on our old 210hp version, much smaller, but still shit, Sherwood pump on those).

http://i139.photobucket.com/albums/q301/bennythewoo/Mountspacers-1.jpg
http://i139.photobucket.com/albums/q301/bennythewoo/spacer.jpg

[The Woo]

Sorry we got so way out of control and sidetracked there everybody!

[Midnight]

Good stuff, you're onto it!

Awesome job so far mate, just had a read on THT.

Cheers

[PB]

I can see why there isn't to many trailer boats around the 7-8m with inboard diesels now, getting everything to work the way we wanted is a pain in the butt, our mission was to design and build a 7.5m mid mount Diesel that can still be towed by a standard 4x4 and i believe we have come up with a great design. we where unable to get the motor under the floor as pushing the motor that far forward played with the hull shape to much and it would have been a pig of a thing, so the motor had to be moved Aft into the middle of the cockpit and stick out of the floor around 250mm but we still have around 900mm between the engine box and the transom giving full access for fishing from port to starboard sides. as the engine box is quite low we have incorporated a rear facing seat and built in storage, live bait tank, drawers, and prep station on top of the engine box.
Now just to bite the bullet and build 1.

[Tinlegs]

Great thread guys and really informative.

I've had small boat diesels ticking over in the back of my head for a while now as my good lady and I think about where we go next with our boating - she's a Sustainability professional, and the environmental impacts of larger boats are being considered in the mix.

Lots of questions have been answered here. Great contribution as always Smithy, Midnight and others.

Don't know anything about these, but it came up when I was looking out of curiosity for a trailerable diesel powered mono and from an internet glance looks a nice boat.

I like how the engine box doesn't intrude too much on the dancefloor and the overhang at rear doesn't look too bad. Where it does intrude is where I usually keep my fish box in my current O/B boat, so a change in fishing style wouldn't be much of a problem for me - that's very subjective though.

Anyway, another one to look at, and we all like to do that.

Seatime 2800

http://www.boatsales.com.au/boats-for-sale/boatdetails.aspx?seot=1&R=11220744&silo=-1&__Ns=pCar_RankSort_Int32%7c1%7c%7cpCar_Price_Decim al%7c1%7c%7cpCar_Make_String%7c0%7c%7cpCar_Model_S tring%7c0&Cr=&trecs=5&__N=1456%20285%204294892288%2079

[PB]

This is a drawing of the first Preliminary design.
http://i638.photobucket.com/albums/uu109/Hemo1984_album/123-PR75MPRELIMINARYARRANGEMENT-page-001.jpg

[The Woo]

Really, the walk-around engine box in the centre of the cockpit isn't a negative at all, MUCh preferable than having to fish around large outboard powerheads in my opinion.
The engine box can serve as a base for a multitude of things.
Game chair
Rocket launchers
Cutting board
Tackle cupboards
Rigging station
Live well
... the list goes on. Any of the above can successfully be incorporated above the engine, making a small boat, "feel" like a big one.

[myusernam]

agreed, pluss you have the advantages of possible eutectic refrigeration, deck wash etc.

[myusernam]

have any of you big boat guys considered running a bypass filtration system (I like the frantz) and getting the oil sampled, changing on condition rather than at intervals? Coulb be major savings and longevity advantages in it for you. Interstate trucks use them (or centerfuges), and get over a million k's out of their donks....

[The Woo]

have any of you big boat guys considered running a bypass filtration system (I like the frantz) and getting the oil sampled, changing on condition rather than at intervals? Coulb be major savings and longevity advantages in it for you. Interstate trucks use them (or centerfuges), and get over a million k's out of their donks....

I feel it's simply easier to just change the oil at intervals. Cost of oil really is quite small in comparison to most of the other costs with these types of boats.
If you were really doing a lot of hours, or had a fleet of boats, then maybe it'd be worth the effort. But for one boat, two engines totalling 30 litres of oil and two filters, not worth it.
If the tests show metal or combustion cotaminents in the oil, well, the engine's already got a problem that needs or will eventually need fixing.

[cormorant]

Even with the small donks we always sample the oil and change at intervals regardless ( smallish cost) as with Ovlovs you really want to know early so you can save up to take out a mortgage and buy parts!!!! Great for maintainance records and resale as well. Just too expensive in parts and downtime to let mechanical wear get out of control as it leads to many other problems fast. Keep it simple in the engine bay unless you are very large and can walk around in there. Hydraulics are another big advantage of the diesels as well in the past but electric/ hydraulics for ligher use stuff is now getting pretty good with bigger batteries and duplicate alternators.

[The Woo]

My point really was that with most common engines, used at apleasure rate of a couple of hundred hours per year, the actual internals of the engine is seldom going to let you down before MANY other things shorten the life of the engine.
A massive overheat or water ingestion from somewhere is usually the killer of engines, long, loooong before the bearings or rings have worn out.

When we ran our baot hard as a charter boat, upwards of 3,000 hrs per year, we did take samples of oil. Nothing was ever amiss inside, but we popped a couple of engines due to silly failures of boat design (gravity works on boats!) or just unlucky (blue-bottle jammed in the intake, paid skipper ignored alarm, throttled on as she slowed!)

[cormorant]

Ahhh Woo I think we were posting at the same time ;D I wasn't replying to your reply. We are both on the same page re - oil changes but we do the tests as a extra and in the past it has served us well to upgrade or rebuild early rather than have a complete failure. The new electronics on the diesels can hide declining performance and with the lighter weight fast spinning ones they can die pretty fast.

[Smithy]

Forgot to add to my post yesterday that Clayton Galants are no more. Saw it on my Facebook yesterday. Clayton Peake has just built his last one for his step-son or son-law or something. Bit of a bugga. Another Aussie boat building icon hanging up his hat. Back to those Witch Crafts, Theodores etc. now!

[PB]

yeah he was trying to sell it for ages, i think he still had heaps of work if he wanted it but he just wanted to retire i was told.

[The Woo]

That is a shame. A long bloodline of building some pretty fantastic boats. Many of the skipperCrafts I'm sure are still in active service.

[Midnight]

PB,
Absolutely nothing wrong with the cockpit layout and dimensions you are quoting. It looks good.

Please do me, and the future owner a favour and factor in a custom exhaust riser, that uses all of the available height under the engine box to get the spill over point as high above the loaded water line as possible. A lot of diesel sterndrives suffer early turbo failure on the exhaust side, as the loaded water line can be within inches of the turbo at rest in some installations. Not a good scenario for longevity.

I hope you get to build what you have drawn and that it works out well. There is a market for it for sure.

Cheers,
Myles

[PB]

Thanks Midnight, i think it will work very well as the main aim was to keep the transom clutter free. We have designed this boat for a client but i would like to build the first one for my self as iv been wanting to do something like this for some tome now.

Cheers PB

[Horse]

I think there is a great future in these 7-9m diesel powered craft. They are just made for visiting the reef and short term live aboard trips. What are the issues with moving the motor further foreward and incorporating a raised helm/bridge rather than an engine box in the cockpit? It would provide plenty of engine access and storage

[PB]

We first looked at placing the motor under the bride but found it played with the boats trim to much and the hull shape would end up being more of a displacement hull rather than a planing hull. Displacement is fine if that's what you want but there not ideal for trailering. Even mounting the motor in the middle of the cockpit had its chalangers, if you look closely at the keel line in the drawing you will see what talking about. Some of the 233 fans might notice it.

[ScottB]

Hi All,

I've been looking for a pic for a few days now, but haven't been able to find, so I figured I would have a go at describing it anyway. Spacecraft Boats in Lake Macquarie have done diesel models in the past with a forward mounted engine in the center of the cockpit, but rather than use a jackshaft, they also mount the leg forward of the transom (on a "false transom" if you like) in a tunnel so that the leg is actually under the cockpit. If you looked at it side on, it would look like the leg was coming out of the bottom of the boat, IPS style.

This would have to offer the best option in terms of fishability, with nothing extending past the transom, and reviews that I can remember reading claim that the handling was excellent. I always wondered why the idea didn't take off, the fishability of a shaft drive and the maneverability of a stern drive.... seems like a pretty good idea to me?

Anyone else have any thoughts on this concept?

Scott

[PB]

Sounds interesting. What size boat was it? The sole height off the water line would have to be very high for it to work.

[ScottB]

Hi PB,

I have seen examples in 6.4m and 8m boats. The engine box is raised as in your design. I have a couple of PDF tests but they are too large to post on here and the pictures aren't that great anyway.

I could email them too you if you want, just PM me your email address.

Scott

[myusernam]

black watch/ deep v 26 used to have slightly raised floor but now have under floor install at transom

[The Woo]

Sounds interesting. What size boat was it? The sole height off the water line would have to be very high for it to work.

I too would imigine a high floor height. Unles the ungine/drive are positioned further aft in the cockpit.

I can also imagine the absolute disaster for service access to the strendrive leg.

[Smithy]

Ben,

just read your thread on THT. Have you been out on any 30' or 34' Black Watches? I wouldn't call a 33' Obrien dry. They are one of the wettest things I have been in. The motion in a sea is the same as a Black Watch running or trolling but the BWs are amazingly dry. I've done a bit of time on Nauti Suzanne which was Parksey's from Townsville. Originally it had sterndrives and then they put a couple of shaft drive SRM33 Fiat/Ivecos in it with a couple of big trim tabs. I like them as boats, they are just bloody wet.

[The Woo]

G'day Smithy, yeah mate, been on 30&34 BW's mate. They are a pretty dry boat, but their motion I feel is very different to an O'B, after all, even the 34's are half the weight of a 33'O'brien, so feel like a trailerboat in comparison ;)
So sure, a 34 BW will ride up and over most waves, bounce off it, and onto the next one, whereby a 33 OB is more likely to shoulder charge through it and give it a fat lip. Gives a MUCH better ride in my opinion, and does shift some water, but they throw it well clear. I've found most spray in really snotty conditions is wind blown, but would never call one "wet".
Bobbie Jones, without doubt one of Oz's most respected skippers, rates the O'Brien miles ahead of a Blackwatch, and he's done time on both.
I've spent time on a few different 33 O'briens too, and given they're all quite differently set up, some are better boats than others, given they are quite fussy on weight placement and trim. They like to be trimmed properly by an attentive skipper (we're instally auto tabs from Bennet this refit, should be great!)
Each one I've been on has had different fual tank placement, different engine packages, even different cabin layouts. I don't think I've ever claimed it was the driest of dry boats, so, how about I say, it's drier than an original 40' O'Brien? And in my very humble opinion, a better boat than a 30/34 Black Watch (which feel like overgrown 25/28 Betrams with their step-down-into saloons and engine boxes - meh) :)

[The Woo]

I've done a bit of time on Nauti Suzanne which was Parksey's from Townsville. Originally it had sterndrives and then they put a couple of shaft drive SRM33 Fiat/Ivecos in it with a couple of big trim tabs.
Our boat was originally "Trpoic Sands" from Townsville, had a tower instead of flybridge.
It then went to Port Douglas, was refited as Shae-Lea".
We bought her from there to Brissy where she became "Illusion".
The old man spoke to Peter O'B prior to purchase to get some history, and Peter said this boat was built with legs and jack shafts, but over the years we've never found evidence of it, and we've looked hard. We always suspected Peter was mistaken re which boat we were talking about, and now it seems, after 20 years, you've shed some light on it Smithy!

[Smithy]

I seen two of the express 33's in the flesh. Burgandy Lady is in Townsville and is the one with all the maroon trim. Brian Norton used to run one down at the Gold Coast called Pegasus. Very similar to the pic on your THT thread. Was it by any chance? I am guessing that one was in Vanuatu was it. Brian bought Diamond Lady the 44' Southern Cross with the tower that Michael Hill (Gold, gold, silver, silver, diamond, diamond man) had. Nauti Suzanne was originally owned by the Suzanne Grae or whatever womenswear people up at Townsville. Funninly enough I have fished on Bad Billy the 30' Black Watch and it was owned by the Bad Billy surfwear company people.

Well one OB is gone. OB1 sunk off Bermie a couple of years ago. Never been on a 40' yet. Keen to see how they go. Would love a run in a 43' too. They are legendary. Jim Dalling always said of all his boats if he had to buy one again it would be OB1. He loved the 33'er.

[The Woo]

I'm saddened to hear OB1 is gone. PM me the details? We're waaaaay off topic here! haha

Pegasus, I do think it's the very same boat now working Vanuatu. I often wonder where Avanti might be too, last I heard she was steaming around to Perth! And Burgandy Lady, she's still up there I presume? Pretty much used as a weekender I assumed when I last saw her.....

If my memory is right, Michael Hill's Diamond Lady was a 52 with a tower (completely feasable if my brain has failed me though!)?
I remember all those years ago it fished the Mooloolaba tournament and I was amazed at how bloody big it was! And thanks! Now it's in my head... Gold, gold, silver, silver chain, chain, sale sale.... Gold gold silver silver chain chain sale sale....

Early 40's without the spray chines are even wetter than a 48 Riv, throw it straight up and over the top (I'd still have one though, good boat, both).... later 40's much better. 43's are apparently mint, but I've only been on one at the dock, never offshore.

It's funny Jim says the same... For us anyway, the 33 is really the perfect boat. Very fuel efficient and affordable to run. As you know, buying them is one thing, running them, another.

[Smithy]

Yeh she might have been a 52. Wonder if it is the Key West hull Russel Caporn just used on his Kaizen. Seems to have been used on a lot of boats. I said 44' as the only other Southern Cross I know is the 44' down at the Gold Coast called 5 Star, now owned by John Faulkner the car racing and Tow Cam guy. Big 44'. Couple of steps up out of the cockpit, massive saloon, etc. Yep be good to know where Avanti is. Pretty famous boat that one. As far as famous goes Cervantes is sitting here going to rack and ruin. Good project for someone. Shorty just has to bite the bullet and let it go for the true market value. Pacemaker is for sale again too.

[The Woo]

Some classics you mention theree for sure. Pacemaker's had some owners! Damned shame to see Cervantes rotting away. Problem with all those boats is the upkeep, timber, and they aren't getting any younger! Geez they've seen some fish though!

Remember Nova Lady? The big Woodnut with a tower? A mate of mine did a big refit on her, then first trip back across the bay in rough conditions, she flamed on shortly after leaving us at Cowan on Moreton. Thanks to a poorly installed upright fridge that somehow tipped over and caused a fire. I have a bunch of pics just before and after.

I remembered today that Michael Hill's boat was a 52, has an enclosed flybridge.

Kaizan was built by Caprocorn boats as you'd know, but you're right, the hull is faintly familiar. I might ask Rob the co-builder when i see him next (lives next door to a friend).

[Smithy]

Are you talking about Dodge (Ron Mally) who had the automatic transmission place? He did up Nova Lady. Yep I know him. One of the first guys I met in gamefishing. Him and Karl (exhaust specialist) that fishes with John Gooding at all the Classic style fishing comps. Dodge has had some boats. Makaira the 34' BW, Mistress I think it was the US 31' Bertie etc. Then there was Fat who had the big sharkcat (Ally Cat?), Jason Rhodes (Stooge) and Owen on Jases Noosacat Stalker. I also know Bernie Smith (no relation) who used to skipper Nova Lady. I remember it doing charters out of Mooloolaba. I have had some of my customers that had been out on it. Fair few stories. I actually fish with Bernie's son Dan quite a bit. I first fished with Dan on Parksey's 40' Black Watch First Class. Bernie and Dan make some good lures that are big in NZ.

[The Woo]

Re Nova Lady, the fella I'm talking about, his name is John, owns a trucking company. He was a half owner in the boat, they must have been partners?
You're bringing up a lot of names I haven't heard for a long time, had sort of drifted away from the scene to build a business and the associated travelling etc took its toll on boat time.
Priorities are back in place now though, and Dad and I are on a mission to get back on the water and enjoy the spoils of nearly three years hard labour. :)