Solas prop selection and will it push the boat

[gazza2006au]

how do u guys think a 50hp mercury 4 stroke will push a quintrex cruiseabout 5 meter boat? its the half alloy half fibreglass model boat alone weighs around 400kg minus engine max hp is 85 since i also dont know the recommended HP it has a 70hp on there now once on a plane it cruises along and does 47kph with 5 people on board
im happy with the mercury 4 stroke 50hp doing a top speed of around 40kph and cruise around 33-35kph

im already planning on using a fast tail hydrofoil on the engine but im lost when it comes to propeller selection i will be looking at a SS solas prop from the US but im unsure what size to buy, the propeller on the 50 mercury is beat up so i cant test that prop i also dont know what size boat the mercury came off of

prop reads 48-73134-A40-12R looking up this propeller in the workshop manual shows it to be dia 10-5/8", 12" pitch, approximate 635-907kg boat weight i would assume this is loaded weight? what would this be converted to solas brand propeller?

[Apollo]

Gazza

I would think that the few $ you might save buying a US Solas could be easily chewed up by buying the wrong spec prop. I was unsure as to what my boat could actually turn efficiently, so opted for sticking with Solas Australia to give me the option to pick their brains and keep changing props at no cost until the right one was achieved. Glad I did, because I ended up trying three different configurations before I was happy. Glad I went the local path. Saved me heaps.

Steve

[Noelm]

50HP on one of those old girls will need a pretty small prop. They had a couple of models, the 4.5, and a 5 and a 5.?? I think the 5 and 5. something had the fibreglass deck.

[patrol50]

mate there is a prop selection app on the mercury web site not sure if it was on the aus one or the yank one - very easy to use and gives you a list of probably suitable choices
cheers

[gazza2006au]

Gazza

I would think that the few $ you might save buying a US Solas could be easily chewed up by buying the wrong spec prop. I was unsure as to what my boat could actually turn efficiently, so opted for sticking with Solas Australia to give me the option to pick their brains and keep changing props at no cost until the right one was achieved. Glad I did, because I ended up trying three different configurations before I was happy. Glad I went the local path. Saved me heaps.

Steve how does that work? i thought once u buy a prop and use it than it becomes yours?


50HP on one of those old girls will need a pretty small prop. They had a couple of models, the 4.5, and a 5 and a 5.?? I think the 5 and 5. something had the fibreglass deck. yeah mate its the 5m model


mate there is a prop selection app on the mercury web site not sure if it was on the aus one or the yank one - very easy to use and gives you a list of probably suitable choices
cheers i just used the calculator its on the usa site i used the weight to calculate the prop needed and one of the props that came up is the one on the engine now thats dinged up

the engine needs to push around 900kg's max loading

[Apollo]

Gazza,

With the Aus solas, they have a guarantee, so you get sent the one they think is right with some testing criteria. You do the water tests and so long as it is not damage in anyway, it can be replaced with another to test and so on until the right solution is achieved. Worth giving them a call to discuss. I found them great to deal with.

Steve

[gazza2006au]

Gazza,

With the Aus solas, they have a guarantee, so you get sent the one they think is right with some testing criteria. You do the water tests and so long as it is not damage in anyway, it can be replaced with another to test and so on until the right solution is achieved. Worth giving them a call to discuss. I found them great to deal with.

Steveyeah i just got a reply they are a bit pricey at $220 a prop the person who replied to my email said this

" thanks for the boat detail and repower specs.
obviouslty the 50 hp merc is going to have to make wide open throttle and we can offer 4 blade compression cast alumium wide blade 10 p best to do the job.

$220 delivered."

[ericcs]

(quote - it has a 70hp on there now once on a plane it cruises along and does 47kph with 5 people on board
im happy with the mercury 4 stroke 50hp doing a top speed of around 40kph and cruise around 33-35kph)

i'm wondering if the 50 will be enough to push the boat and 5 people fast enough regardless of what prop combination?

[FishHunter]

I suspect the 50hp will be underpowered and another vote for Solas Australia

[gazza2006au]

(quote - it has a 70hp on there now once on a plane it cruises along and does 47kph with 5 people on board
im happy with the mercury 4 stroke 50hp doing a top speed of around 40kph and cruise around 33-35kph)

i'm wondering if the 50 will be enough to push the boat and 5 people fast enough regardless of what prop combination?i will only be taking 4 people on board once the 50hp is on there and without a hydrofoil the boat planes at around 22-25kph so im hopping it isnt under powered to the point i cannot get up on the plane but im sure the hydrofoil i plan on buying will help

as the boat is with the old 70hp evinrude it does close to 60kph with 3 people on board its just more of the seating arrangement in my boat i cant really do anything about the weight is mid to rear of the boat plus a 35L bait tank doesnt help getting on the plane

i think running the 50hp 4 stroke with a hydrofoil and the correct prop for acceleration with a average top speed i should be ok what do u guys think? what are u guys getting speed wise from your 50hp 4 strokes?

[johncar]

If you are unsure as to prop selection another vote for the local Solas guys, they have looked after me with a few boats now and saved me plenty of $$$$ and stress for sure.
The 50hp should push the boat along OK with the right prop but you will have to be careful with your selection that you don't load the engine with too steep a pitch and diameter which is where Solas come in.
I had a 4.3 metre Fishabout version of the above boat with a 40HP 2 stroke Johnno on the back and it went well with 3 on board and I now own a 5 metre plate ally centre console with a 90HP 4 stroke which goes well with 3 on board so from what I know I think that the 50 on the back of the Quinnie may struggle a bit loaded up with a few people on board.
Anyhow if you are locked into the 50hp engine then the Local prop guys are going to be your best bet rather than trial and error and ending up with redundant props to have to later try and sell.

[wrxhoon]

If solas recommend a 10"p you can work out the speed you will be doing at any given revs, to do this you need to know the gear ratio. As a rule allow for 10% slip.
If it's not a big foot it should be 1.83 By my calcs you will be going around 41 kmh at 5500 rpm, from there calculate your speed at any given rpm.
It's not going to be powerhouse and you have to run it on the high side of your rpm range.

If you go on this site you can check out boat tests: http://www.mercurymarine.com/engines/engine-tests/outboards/

Not two boats are the same but you will find one with the same weight as yours to compare.
I would buy a 4 blade S/S prop , they are cheap enough in USA. With the prices there you can afford to have two props, one for light loads and one for heavy loads.

[gofishin]

Let’s assume:
· Actual power of both motors is their rated power (i.e. number on the donk),
· Current prop is suited to the 70 & the boat/loading conditions,
· New prop on the 50 performs to a similar level (i.e. slip) as the 70 & its prop,
· Loading conditions do not change,
· “close to 60km/h” means 58km/h (???), and
· The wind will always be behind you with your 50, and you’re always on a down-hill lake….nah, actually just threw thatin to see who has kept reading, but it would help J

The ‘expected’ top speed will be approx.; 58x SQRT(50/70) = 49km/h! However…!

The boat will be underpowered, meaning it needs to be propped to help get it on the plane/over the hump! Take off maybe 3 –4 km/h for this, another 3 – 4 for the foil, and you’ve got your 40km/h top speed! Cruising at your expected 35 will see your 50 screaming near WOT all the time!

Definitely go to the local SOLAS boys. Any small savings you would get on a ~$220 prop would not be worth the hassle – especially in this case, IMHO. Ask them to give you a “second choice” (or third) selection to try at the same time, and keep the best one - and pay for one!
Cheers
Brendon

[gazza2006au]

If you are unsure as to prop selection another vote for the local Solas guys, they have looked after me with a few boats now and saved me plenty of $$$$ and stress for sure.
The 50hp should push the boat along OK with the right prop but you will have to be careful with your selection that you don't load the engine with too steep a pitch and diameter which is where Solas come in.
I had a 4.3 metre Fishabout version of the above boat with a 40HP 2 stroke Johnno on the back and it went well with 3 on board and I now own a 5 metre plate ally centre console with a 90HP 4 stroke which goes well with 3 on board so from what I know I think that the 50 on the back of the Quinnie may struggle a bit loaded up with a few people on board.
Anyhow if you are locked into the 50hp engine then the Local prop guys are going to be your best bet rather than trial and error and ending up with redundant props to have to later try and sell. i do have the option of selling both the mercury 50hp and evinrude 70hp for something a little bigger but the catch is my boat is rated 85hp max which will be 2 stroke transom weight and a 75hp 4 stroke is over 150kg considerably heavier than the 100kg 70hp evinrude on there now thats why i want to use the mercury 50hp as its about 100kg


If solas recommend a 10"p you can work out the speed you will be doing at any given revs, to do this you need to know the gear ratio. As a rule allow for 10% slip.
If it's not a big foot it should be 1.83 By my calcs you will be going around 41 kmh at 5500 rpm, from there calculate your speed at any given rpm.
It's not going to be powerhouse and you have to run it on the high side of your rpm range.

If you go on this site you can check out boat tests: http://www.mercurymarine.com/engines...sts/outboards/ (http://www.mercurymarine.com/engines/engine-tests/outboards/)

Not two boats are the same but you will find one with the same weight as yours to compare.
I would buy a 4 blade S/S prop , they are cheap enough in USA. With the prices there you can afford to have two props, one for light loads and one for heavy loads. yeah mate its just the standard model with the 1.83 gearbox just says on the sticker max 6000 RPM and i dont mind running it flat out if i get 40kph at full throttle it still leaves some to spare as i was out a couple of days ago in the bay 32-33kph felt a nice speed running across the chop anything more just gives me a sore back my main concern would be getting on the plane loaded and holding that position
i would get the prop from the USA but i dont know which one to buy lol solas said to go with a 4 blade, 10P but i dont know what diameter and without a tachometer i wont know what RPM ill be doing unless i installed a gauge


Let’s assume:
· Actual power of both motors is their rated power (i.e. number on the donk),
· Current prop is suited to the 70 & the boat/loading conditions,
· New prop on the 50 performs to a similar level (i.e. slip) as the 70 & its prop,
· Loading conditions do not change,
· “close to 60km/h” means 58km/h (???), and
· The wind will always be behind you with your 50, and you’re always on a down-hill lake….nah, actually just threw thatin to see who has kept reading, but it would help J

The ‘expected’ top speed will be approx.; 58x SQRT(50/70) = 49km/h! However…!

The boat will be underpowered, meaning it needs to be propped to help get it on the plane/over the hump! Take off maybe 3 –4 km/h for this, another 3 – 4 for the foil, and you’ve got your 40km/h top speed! Cruising at your expected 35 will see your 50 screaming near WOT all the time!

Definitely go to the local SOLAS boys. Any small savings you would get on a ~$220 prop would not be worth the hassle – especially in this case, IMHO. Ask them to give you a “second choice” (or third) selection to try at the same time, and keep the best one - and pay for one!
Cheers
Brendon the fast tail hydrofoil increases speed not reduces it so hopefully cancels out the different propeller size needed to over come the take off hopefully maybe im trying to convince my self


ill see how it goes guys i looked at the mercury reviews a similar boat to mine in weight and lenght was doing 29mph with the newer EFI 50hp mercury so it cant be to much of a loss in comparison

[Crocodile]

Hello Gazza,
that is a lot of boat to push with a 50.
Most of the those boats have a 70 and there is a good reason for that.
IMHO you will be very disappointed with the performance and the 50 will have to rev its guts out just to stay on the plane.
Why are you doing this? is the 70 kaput?

[gofishin]

... the fast tail hydrofoil increases speed not reduces it... don't believe the marketing hype. Anything that creates lift creates drag - that's physics. Your boat has an external keel, so the donk will need to be lower than for a glass hull. This means the foil will be 'under' even at WOT. This means drag.

A foil may help you on to the plane, and maintain a plane at a lower speed, but it ain't going to make you go faster!



...maybe im trying to convince my self ... maybe! :)

[patrol50]

as other suggest i think you will be a bit underpowered with the 50 - i had a merc 50 4s on my 470 coastrunner and it was just ok for 2 but not so ok for 3 when fully loaded up and in a bit of a chop etc - so i went up to a 60 4s ( max rated hp for the 470 cr at that time and also went for the big foot with a 4 b alum 13.8 x 13 prop but its still very early in its use so cannt really comment properly on the change up yet but its looking pretty ok

couple of comments - a 60 big foot either in a merc 4 s (118 kg dry wt ) or the yamaha 60 hp with the heavy duty gear box unit would be a pretty good option for you possibly and if you go for a 4 b prop on the current 50 hp motor maybe be a bit careful if you go SS as i have been told the ss 4 b can put quite a load on the gearbox and if its not a heavy duty gearbox ie a big foot then that may cause an issue in the future - a 4 b alum prop is probably ok though -
cheers

[ericcs]

a foil will get you a faster hole shot onto the plane, but won't give give you a faster top end. the extra drag will certainly clip some rpm's

[gazza2006au]

thanks guys there is nothing wrong with the 70 i just want a more modern engine on my boat and i scored the 50 for cheap plus its a 4 stroke that is desirable as it will use half the fuel as the 70 munches the fuel, i was looking last night on ebay USA a new 60hp mercury is only $5500 ive been quoted previously by a aussie shipping company $500 to import a engine from the USA but than i thought to my self will that extra 10hp really make that big of a difference? i also looked at the other side its only 10hp short of what i have now too

[thelump]

Sorry to mess with your head gazza but another option would be a new 2 stroke. Something in the 60 - 70hp will be cheaper to buy, and not to bad to run. I would think you are not doing massive trips in the old quinny so fuel would not be that big an issue. And they would have a fair bit more punch than an equivelant sized 4 stroke. Just a thought!

[Crocodile]

Hello Gazza,
If the 70 is OK keep it, sell the 50, the proceeds will buy a lot of fuel.
Enjoy the performance of the 70.
I once test drove a 15 Quinnie, a much smaller and lighter boat than yours, with a 50hp Mariner 4 stroke, same engine as the Merc.
With four adults on board it needed 5000rpm to stay on the plane and was sluggish at all times. As it was revving so high it made an awful high pitched screaming note that was really unpleasant.
If you want a more modern motor trade them both in on a modern two stroke and enjoy the easy performance. Unless you do hundreds of hours a 4 stroke will never save enough petrol to justify the extra cost and reduction in performance.
Also you don't want to over-capitalise on an older boat.

[gazza2006au]

Hello Gazza,
If the 70 is OK keep it, sell the 50, the proceeds will buy a lot of fuel.
Enjoy the performance of the 70.
I once test drove a 15 Quinnie, a much smaller and lighter boat than yours, with a 50hp Mariner 4 stroke, same engine as the Merc.
With four adults on board it needed 5000rpm to stay on the plane and was sluggish at all times. As it was revving so high it made an awful high pitched screaming note that was really unpleasant.
If you want a more modern motor trade them both in on a modern two stroke and enjoy the easy performance. Unless you do hundreds of hours a 4 stroke will never save enough petrol to justify the extra cost and reduction in performance.
Also you don't want to over-capitalise on an older boat.
with my current 70 2S when im driving across the bay i can watch my fuel gauge go down it uses that much petrol lol thats why i want a 4 stroke and no oil mixing as i have a underfloor tank its a pain in the ass filling up a jerry can than mixing the oil than pouring that in and doing it again to fill up, ive just looked at the prices on a new 60hp tohatsu $6900 a bit pricey considering a new 4 stroke 60hp in the usa is only $5500 plus shipping so the 4 stroke is very appealing

[thelump]

Gazza there are quite a few posts on here re importing motors from the US. Use the search option and have a read mate. If it worked out that cheap everyone would be doing it. Check it out mate. It may not save you as much as you think. Also make sure that the price includes all the rigging and gauges etc as a lot of places advertise just the motor itself.
Good luck whatever way you go.

[Darren Mc]

Just for your info, the yamaha 4 stroke 70hp is 120kg. That wouldn't be to bad.
Might be a bit to dear though.

[Horse]

Gazza, Macca is on the money. Most US sites quote a price without rigging and guages and also no prop. Add your GST to the whole thing and consider you are a long way away from warranty work then its a lot less attractive

[Spaniard_King]

Don't sell that 70 until you have run the 50 on the boat !!!!

[Smithy]

Those two stroke 70s should be getting you 1nm/l. Not too bad and with 800cc they are pretty ballsy. I think the 50 is going to be a struggle.

[Moonlighter]

I do recall many years ago seeing quite a few of those Quintrex 16ft/5m boats around, they were pretty popular.

I saw quite a few running the old Johnson twin cyl 55 hp motors. Remember in those days they werent rated at the prop, so 50 modern, new horses will be at least as good as one of those old 55 Johnnos when they were new.

So i think it might be worth giving it a shot with the 50 Merc 4 stroke. It wont be a speed machine, and you will need to get it propped right. Seve at Solas it pretty damn good with picking props in these sutuations, and yes, he will help you out with swaps until you bet things right. Make sure you test it with the typical load yo are expecting to run, and not just in light trim mode.

Good luck.

[gazza2006au]

i may only be putting the 50hp on the boat to test it before i sell the 50hp im still looking into the 60hp bigfoot from the USA gauges and remote control arnt a big deal if i still save $2000 off buying a engine here thats a fair amount of money for me
i seen a couple of tinnies yesterday while out on the water both were over the 4.5m size one had a standard engine the other had the bigfoot both 60hp new models so seeing those boats im sure the 60hp will push mine with the bigfoot gearbox

[patrol50]

gazza i am no expert but i reckon a merc 60 hp 4s bigfoot ( or similar ob in the yam ) would do that job on your boat ok but then i guess so would a honda 60 and suzuki etc - the new merc 60 4 s big foot certainly pushes mine along no prob but my ob is still very new though so have not had it at wot yet - and mate just wondering aloud do you really think its worth it to import one as you still need the gauges throttle controls etc and someone has to fit it up if you cant do it yourself - maybe check with merc aus re if the warranty is transferrable to aus if you do import a merc from usa ( or similarly for a yam if thats your choice ) - and also is warranty still applicable if you do the installation work yourself as merc in particular seem pretty vocal about using accredited dealers for all service work to maintain the warranty

to my own not small surprise when i bought my merc 60 big foot recently i found out they are made in china now or so the tiny writing on the motor sticker says and so it could be good to have warranty cover available as a fall back if needed - its a long way to send it back to the good ole usa if it plays up
cheers and good luck

[wrxhoon]

with my current 70 2S when im driving across the bay i can watch my fuel gauge go down it uses that much petrol lol thats why i want a 4 stroke and no oil mixing as i have a underfloor tank its a pain in the ass filling up a jerry can than mixing the oil than pouring that in and doing it again to fill up, ive just looked at the prices on a new 60hp tohatsu $6900 a bit pricey considering a new 4 stroke 60hp in the usa is only $5500 plus shipping so the 4 stroke is very appealing

Don't forget the GST, customs entry , customs agent ( unless you do it yourself) and Q/T entry, ah engines sold new in USA are just that , engine only , no prop, no gauges, no controls, no fitting included and NO warranty outside USA. Do all the sums, then compare.

You don't need to worry about prop diameter so much, it's the pitch that will make the difference, as a rule a larger diameter prop suits a heavy bot and a small diameter suits a light boat.

[gazza2006au]

Don't forget the GST, customs entry , customs agent ( unless you do it yourself) and Q/T entry, ah engines sold new in USA are just that , engine only , no prop, no gauges, no controls, no fitting included and NO warranty outside USA. Do all the sums, then compare.

You don't need to worry about prop diameter so much, it's the pitch that will make the difference, as a rule a larger diameter prop suits a heavy bot and a small diameter suits a light boat.

i received this email this morning from the aussie shipping company

"
Hi gary
no problems and if new no quarantine.

Need to have a declaration on the invoice stating new and not field tested etc.

Total cost would be a$575 incl packing usa/export clearance/shipping/unpack aust/customs clearance

Marine insurance would be minimum at a$185

Attached is the export form we require completed and send to in our office

This also has the address of our depot in paramount LA if you have delivered or we can organise pick up. "

i really like the option this company can pick up the engine from the dealer as well

[patrol50]

id be checlking on that customs clearance total $ quote mate and if it includes all customs charges and any applicable aus gst or customs import duty payments - can be a difference between custom clearance ( item quarantine and physical or sight check of the items by customs officers etc ) and then the actual release of the imported items to you - i have never imported an outboard motor - but i have had sent back to aus some souvenir africa curios after a recent trip to africa and then shelled out an unexpected additional customs import duty charge of quite a few more hundred dollars to have the items released to me at bris airport after a physical inspection and clearance by custom officers (at a further extra charge) - so just a word of warning as i believe any imported item in excess of $1000 value ( unless its a gift ) attracts a gst or a customs import duty charge of 10 % payable by the importer / receiver prior to its release - and the selling dealer and or the shipping companies dont always let you know that an extra charge on pick up or delivery is waiting to hit you
cheers

[wrxhoon]

Gazza
you will pay GST mate, someone has to pay Juliar, actually we all do..

[gazza2006au]

yeah the importer said 10% GST is payable im still ok with that extra fee, but what i dont get is some 5 year old engines are close to the cost of a new engine on the usa ebay
i would love one of those yamaha F70's *drools* but a bit much for what i can afford

[oldie]

From what i have read in the past unless you have an address in the states No dealer will sell you a new motor, I may be wrong!? but have read this on a heap of different threads and forums.

Controls and cables here in OZ will cost you at least $900-1k not sure on the price state side. add GST to your $6900 ($690) plus your import cost ($575) the insurance($185) plus i'd allow at least $500 buffer for the un forseen costs involved, then whether your paying someone to fit it $500 Kinda starts looking like the new Oz motor for what $8500-9k including 5 year warranty is the best option. Don't think the USA motors include Prop Either, reading in fishing monthly they have $500 cash back at the moment too on 40-60hp

[nigelr]

Perhaps have a look at the Tohatsu M70C....very well priced. Have to agree, think a 50 4 banger will dissapoint with performance, especially if you ever need it.

[oldie]

sorry just relized i said $6900 your price was $5500

[gazza2006au]

yeah mate the new tohatsu 70hp 2 stroke are $6900 the amercian mercury 60hp 4 strokes vairy there was one on ebay for $5300 new but the only ones left now are $6000 and the dealer ships international i was quoted $980 to any australian port for this engine http://www.ebay.com/itm/220929180987?item=220929180987&viewitem=&sspagename=ADME:X:RTQ:MOTORS:1123&vxp=mtr
im trying to sell the 50hp mercury now its on ebay

[patrol50]

your a braver man than me gazza to import a new merc 60 hp 4 s from the usa mate and risk no easy access to warranty cover etc but i hope it works out really well for you
good luck
cheers rob
ps maybe a good plan to get the gauges and throttle connection and a prop all sent out with it ???

[Spaniard_King]

your a braver man than me gazza to import a new merc 60 hp 4 s from the usa mate and risk no easy access to warranty cover etc ( the merc 60 4 s incidently are now made in china or so the tiny sticker on my brand new one says that) but i hope it works out really well for you
good luck
cheers rob
ps maybe a good plan to get the gauges and throttle connection and a prop all sent out with it ???


If ya goin to that trouble may as well get a boat with it.. save on rigging costs :)

[stevemid]

70 Yamaha =120kg??? 10,200 fitted at Bris Yammie