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KingyKing
20-04-2016, 03:24 PM
Found this over on THT site, Looks pretty cool. Looks like its heading over to WA.
http://www.thehulltruth.com/showthread.php?t=750594

swof63
20-04-2016, 04:49 PM
Interesting. I think the theory is to introduce aerated water under the hull to "unstick" it and reduce drag.
Counterpoint to that is I wouldn't want to be the bunny that has to get the sounder working with all that air underneath, and the unaerated hull is a long way forward so maybe coming out of the water offshore. I'm sure they have a solution if it's not Pelagics first one. Never seen one done in ally before mainly US plastic boats.

cheers

Chris Tucker
20-04-2016, 05:47 PM
Steps work by increasing the aspect ratio of the lifting area and thus the efficiency. So with this boat where we've used 1.5 steps it would be like having a 6m wide transom. Dans previous stepped hull boats have been built for the coast guard so a transducer wasn't an issue. The hammerhead stepped hull boats have all had transom mount transducers.

scottar
20-04-2016, 09:13 PM
Steps work by increasing the aspect ratio of the lifting area and thus the efficiency. So with this boat where we've used 1.5 steps it would be like having a 6m wide transom. Dans previous stepped hull boats have been built for the coast guard so a transducer wasn't an issue. The hammerhead stepped hull boats have all had transom mount transducers.

So in laymans terms after a bit of reading - they are using the steps to generate low pressure areas to keep the water under the hull instead of it being pushed aside - thus generating more lift ????

Triple
21-04-2016, 07:50 AM
I had to google it..
http://www.navaldesign.co.za/articles/Stepped%20Hulls-%20Feb07.pdf

Chris Tucker
21-04-2016, 08:14 AM
That is a pretty good article.

The last paragraph is part of the important part. There are challenges in getting stepped hull design right. On a race /patrol boat it is quite easy because you know where all the weight will be 95% of the time. On a pleasure boat it is harder because load and weight location can vary a great deal. If you get the design wrong you'll either end up with a boat that broaches badly going through waves or constantly points for the sky and pounds like a pig. I have a few tricks and techniques I use to make these small stepped hull boats work and easily be driven by the pleasure boat owner, but for commercial reasons I won't be divulging them here. There have been some rumours of late of a couple of yards working on their own stepped hull designs having seen what we're doing at Hammerhead and Pelagic for the last 4 years. It will be interesting to see what they come up with because these aren't hulls you can loft up by eye on the shop floor.

PB
21-04-2016, 05:29 PM
Interesting. I think the theory is to introduce aerated water under the hull to "unstick" it and reduce drag.
Counterpoint to that is I wouldn't want to be the bunny that has to get the sounder working with all that air underneath, and the unaerated hull is a long way forward so maybe coming out of the water offshore. I'm sure they have a solution if it's not Pelagics first one. Never seen one done in ally before mainly US plastic boats.

cheers

The transducer placement on any boat can be a challenge and we did find that the placement on the pervious boats wasn't up to my standard but we were also somewhat limited as the clients weren't willing to spend the money on thru hull and wet faced Transducers.
It's a completely different story with this boat as the customer is prepared to spend the money on high end transducers and is willing to pay for the time needed to install them correctly. At this stage at least 1 trany will be wet faced just forward of the 1st step.
With regards to the Steps we are extremely happy and somewhat blown away with the performance on our pervious boats hence the reasons for going to the next level with this and future boats. IMO its differently worth the extra time and money required to build these hulls.

myusernam
21-04-2016, 07:07 PM
thats a lot of stuffing around for a creek boat

Lovey80
21-04-2016, 11:51 PM
Chris,

when is the next big ally cat going to be designed with a stepped hull?

Chris Tucker
22-04-2016, 08:25 AM
Chris,

when is the next big ally cat going to be designed with a stepped hull?

I've been working on one off and on with Metal Shark Boats in the States. But have not yet been able to satisfy myself that it will work better than a normal planning cat. For stepped hulls to offer an advantage the vents at the front of each step have to allow clear flow of air behind each step. Failure to do so means that each step actually becomes a brake. On race boats this isn't an issue because they are always fully high on the plane so getting air in the vents is easy. Patrol boats tend to operate at 5-10 knots or 40+ knots and rarely anything in between. This means they don't spend time around the planing hump which can become huge if the vents aren't working properly. Unfortunately pleasure boats have to be efficient across the full range of speeds.

On symmetrical hull planing cats the water line actually rises between the hulls until you are going very quick. This makes venting the inner half of the hull very problematic. To do it properly you actually have to vent air down through the hull (not particularly practical on a pleasure boat. The other alternative is to go with an asymmetric hull form, which have their own foibles particularly in quartering seas.

A good example of the dilemma is the Freeman 37. It does about 47 knots with twin Yamaha 350s. According to their web page this boat weights in at 5.2-6 tonne, now any well designed symmetrical hull planing cat will do about 40 knots if fitted with 100HP/Tonne. So a pair of 275hp engines should power the boat to 40 knots and 2x350 hp would give a speed around 47 knots, which begs the question. On this boat what are the steps providing?

KingyKing
22-04-2016, 09:56 AM
Pretty awesome if you ask me and its has some great lines, Looking forward to seeing it up the right way.
http://i638.photobucket.com/albums/uu109/Hemo1984_album/IMG_2623_zpslfw8ydl8.jpg (http://s638.photobucket.com/user/Hemo1984_album/media/IMG_2623_zpslfw8ydl8.jpg.html)

KingyKing
03-05-2016, 09:17 AM
She has been rolled over, this is one great looking boat I wonder what sort of invstment would be needed to get a boat of this size and type on the water?

http://i638.photobucket.com/albums/uu109/Hemo1984_album/IMG_2695_zpsjvnsx8xm.jpg (http://s638.photobucket.com/user/Hemo1984_album/media/IMG_2695_zpsjvnsx8xm.jpg.html)

http://i638.photobucket.com/albums/uu109/Hemo1984_album/IMG_2698_zps48kyo3zz.jpg (http://s638.photobucket.com/user/Hemo1984_album/media/IMG_2698_zps48kyo3zz.jpg.html)

Chimo
03-05-2016, 09:29 AM
Whats the story with the offset cab on the cat in back of the mono?

KingyKing
03-05-2016, 09:38 AM
No Idea mate, Hopefully PB or Chris Tucker can fill us in.

Luke G
03-05-2016, 09:43 AM
300k is my guess, maby more.

Chris Tucker
03-05-2016, 01:38 PM
Can't answer on price. Not my place and we have to be careful not to overstep the bounds and turn the thread into an ad. best bet would be to contact Dan direct.

The cat in the background is being built to survey. The cabin is symmetrical but the roof extends out to the port gunwale. The client services Nav marks and needs to be able to access the solar panels and the lights on top. The roof gives them a platform to stand on while doing that. As weight/payload were considered more important than aesthetics, the roof ended up offset to one side.

myusernam
03-05-2016, 04:25 PM
seems to me if you wanted a stepped hull in a boat like that you could import a used one from the states and it would be proven, glass and heaps better.

Chris Tucker
03-05-2016, 04:56 PM
Go for it. But then this one is being built to survey and its not our first stepped hulled ali boat.

tunaticer
03-05-2016, 06:35 PM
Whilst labour content increases, material may well be more cost effective due to easier nesting on the stock sheets.
Stepped hulls is not a new concept or practice.......does lead to more areas where cracks can appear though.
Benefits are you can get a sharper entry and better flare.

reelally
03-05-2016, 07:30 PM
Go for it. But then this one is being built to survey and its not our first stepped hulled ali boat.

Looks good. Love to see people not afraid to think outside the square in ally!
What class survey and standards is it being built to?

The build quality looks awesome, going to be a weapon!

Chris Tucker
03-05-2016, 07:38 PM
Boat is going into 2c with structures to Lloyds (as required for high load vessels) and has been engineered for speeds over 50 knots. To my knowledge will be one of if not the fastest charter vessel in Australia.

scottar
03-05-2016, 08:24 PM
Stepped hulls definitely not new in Aus or in aluminium. Most of the ones I have had anything to do with have had a big inflatable sausage wrapped around the outside and around 1200 - 1400 Hp strapped to the back - they tend to go allright

reelally
03-05-2016, 08:33 PM
Should be a tough rig! Lloyds standards are full on, I bet the welders are over all of the double continuous welding on all the Longitudinals below the waterline!

Chris Tucker
03-05-2016, 08:54 PM
In theory as a charter boat we could have gone with iso12215 for the structures. But it's hard to make a case for a boat of this performance being lightly loaded. None of the photos that have been posted give you a real feel for how much structure is in the boat (or the amount of welding)

myusernam
04-05-2016, 08:20 AM
is it going to be a people mover / tourist type thing?

Chris Tucker
04-05-2016, 08:38 AM
Sports fishing: https://www.facebook.com/Black-Blue-Marlin-Charters-Exmouth-1072940256080497/

PB
04-05-2016, 10:03 AM
The hole stepped hull theory is not new it's been around for a long long time, but a stepped hull being 100% designed and build in Australia is a relatively new thing this will be our 3rd stepped hull that we have done with Chris and we are extremely happy with the past result and can't wait to get this one on the water. We have been doing this long enough now that I already know this hull is going to blow the competition away. Our client was pretty close to buying a new 30' Contender (and also a couple of AUS built glass boats) but they couldn't guarantee some of the survey requirement where we could they also couldn't do some of the customisation they wanted hence the reason for contracting us to build his dream boat.

gofishin
04-05-2016, 12:59 PM
Although stepped hulls (and in alloy) are not new by any means (well overseas at least), it’s really great to see this sort of ‘innovation’ being introduced and actively promoted by companies and NA’s such as Pelagic Boats and Chris T – well in my mind at least. Well done boys, and thanks for the additional comments ! I find this stuff really interesting.

Our glass boat ‘trailer boat’ builders will probably never be able to be at (or even aim for) the pointy end of their game internationally, let alone have the means to introduce innovation such as this (due to the very small market size). However, I think some of our custom alloy boat builders (and associated technical people) are right up there… case in point! It’s nice to see the yanks ‘oogling at our tinnies’ too J .

The saying ‘there is more than one way to skin a cat’ obviously also holds true with ‘step theory/design’ in alloy boats. Anyone else notice the difference in recent(ish) threads on THT where there are good hull pics of stepped alloy hulls?

I notice your steps (hollows/air passages??) are quite large in comparison to some others Chris, plus also the design and shape(s) of the aft running/planing surface(s). Is the former purely for more air/to reduce the chance of ‘no air’ situations under the hull?

50kn with 2 x 250’s in a heavy survey 28’ x 9.5’ “tinny” is pretty darn good I reckon.

myusernam
04-05-2016, 02:04 PM
i dunno. I have seen steps on some average plate tinnys up here and have to question their validity. Other than a point of difference I doubt their benifit. From what I have read their benifit is debateable and the design pioints hard to get right, even for the big US companies. But when they are on sub twenty foot tinnys with lazy four strokes that would be lucky to see 35 knots I have to question their benifit. Especially on short, fat , wide, shallow V, high volume tinnies marketed as bluewater boats

PB
04-05-2016, 02:24 PM
i dunno. I have seen steps on some average plate tinnys up here and have to question their validity. Other than a point of difference I doubt their benifit. From what I have read their benifit is debateable and the design pioints hard to get right, even for the big US companies. But when they are on sub twenty foot tinnys with lazy four strokes that would be lucky to see 35 knots I have to question their benifit. Especially on short, fat , wide, shallow V, high volume tinnies marketed as bluewater boats

The boat is 28 foot long, and will do over 50 knts. There is a good reason pretty much all of the big name US builders are doing it and its simple, it works. Im happy to take you for a run in it once its finished.

PROS
04-05-2016, 02:28 PM
do they need to travel a very long way to fishing grounds at Exmouth?

Luke G
04-05-2016, 02:30 PM
Nup its not far at all of exmouth, 20kms and your in blue marlin territory

Chris Tucker
04-05-2016, 03:01 PM
The saying ‘there is more than one way to skin a cat’ obviously also holds true with ‘step theory/design’ in alloy boats. Anyone else notice the difference in recent(ish) threads on THT where there are good hull pics of stepped alloy hulls?

I notice your steps (hollows/air passages??) are quite large in comparison to some others Chris, plus also the design and shape(s) of the aft running/planing surface(s). Is the former purely for more air/to reduce the chance of ‘no air’ situations under the hull?


Part of the difference is to do with the equipment Pelagic have on hand. The vents are designed to be made with a break press rather than rolled. This in combination with my desire to make sure there is plenty of air access, leads to the different vent geometry. The actual steps are actually typically smaller than what a lot of people build you only need 10-15mm of step for it to "work" but actual step size is defined by the desired buttock angle of the separate planing surfaces. The other difference you'll see when compared to the Metal shark boats (also being shown on "The Hull Truth") is that the aft step geometry is almost inversed. I think I know what they're trying to achieve with theirs (haven't spoken to them about it) and believe we achieve similar goals without sucking the back of the boat down.

myusernam
04-05-2016, 03:03 PM
The boat is 28 foot long, and will do over 50 knts. There is a good reason pretty much all of the big name US builders are doing it and its simple, it works. Im happy to take you for a run in it once its finished.
sorry mate i wasnt referring to your build. slightly ot. tjheres a builder in nq doing them to coastal tinnys. I thought chris might have some opinion

Chris Tucker
04-05-2016, 03:12 PM
This was the first step hull boat I did. Top speed 60 MPH (52 knots). Cruises out to the reef at over 40 knots on Auto pilot. The Pelagic boat is lighter and has a more evolved hull shape (as I said attached was the first).

https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-xfp1/t31.0-8/12715849_1047902098601584_3726327117467207894_o.jp g

Chris Tucker
04-05-2016, 03:20 PM
sorry mate i wasnt referring to your build. slightly ot. tjheres a builder in nq doing them to coastal tinnys. I thought chris might have some opinion

I'm assuming you're talking about Hammerhead (as shown above) have you been for a ride on one of his stepped hull boats? They re-define efficiency and ride. We've drawn the line on the Hammerhead range at 6m for the stepped hulls as there is definitely a diminishing return. Having said that, we have stepped the chine on his Firefly range but this works in different ways and is to allow oversized heavily angled chines forward for a smooth dry ride without effecting ride or handling.

The owner of the 8m loves his boat so much he now regularly does favours for Hammerhead without accepting and reward. (Thanks Stevo)

myusernam
04-05-2016, 03:54 PM
it was the firefly range i was talking about. cant see the point - seems to be just a marketing thing for mine.
I have been in a 5.3 firefly. I dont understand why plate builders build hgh volume low deadrise, short, fat, power hungry offshore boats.
Seems to me to be a good nt river design. but not a coastal fisher which is its purpose. putting a step on it at the speeds it will be travelling is just a marketing ploy IMHO. Hammerhead call their stepped hull "unique" and well they're not really. But they are mainly used on high speed deep v hulls. which again begs the question

Chris Tucker
04-05-2016, 04:24 PM
There is no such thing as a 5.3m Firefly, they come in 4.5 and 4.8m. It must have been a Dragonfly you were on which has a high deadrise for a plate boat of its size of boat. Like all the Hammerhead boats the 5.3m Dragonfly was original designed and built based upon a client's specification and requirements for an offshore capable boat. The only boat Gerard has ever built on "spec" is the Sandfly, a V'nosed punt (pictured) which had some construction ideas we wanted to try before releasing it onto the market.

https://scontent-lax3-1.xx.fbcdn.net/t31.0-8/12402171_1029729467085514_3948039676969276017_o.jp g

The Firefly is a low deadrise (12 degree) creek boat with large (oversize) reverse chines. Generally speaking, people loved the firefly's awesome stability and dry spray free ride. However, the feedback we were getting from clients was it was very sensitive to the trim button on the outboard. So we cut away the back part of the chine (hull bottom is continuous and unchanged from the original).

113009113010

This has resulted in a boat that has the smooth dry ride and awesome stability of the early Firefly hulls while also being easier to drive. in short this is very different to a stepped hull and actually has the opposite effect.


https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-xft1/t31.0-8/11182751_901694833222312_4177260638330727429_o.jpg

Chris Tucker
04-05-2016, 04:41 PM
do they need to travel a very long way to fishing grounds at Exmouth?

More than anything else Richard is trying to put together a unique fishing experience. You'll be the first out to the grounds and the last to leave, add a few other commercially sensitive features and he should be on a winner. Keep an eye on his facebook (https://www.facebook.com/Black-Blue-Marlin-Charters-Exmouth-1072940256080497/) page for more

dodgyone
18-05-2016, 03:18 PM
More than anything else Richard is trying to put together a unique fishing experience. You'll be the first out to the grounds and the last to leave, add a few other commercially sensitive features and he should be on a winner. Keep an eye on his facebook (https://www.facebook.com/Black-Blue-Marlin-Charters-Exmouth-1072940256080497/) page for more

Hmmm. How will it come off the trailer at low tide at tantas?

Chris Tucker
18-05-2016, 03:48 PM
This is the main disadvantage of the double steps on this boat as against the Continuous Keel Stepped Hulls as seen on the Hammerhead boats and the Pelagic Coastguard boats. Dan's trailers are a work of art so I'm sure he has it covered.

Noelm
18-05-2016, 05:39 PM
In that last picture of the centre console, the step is completely clear of the water, so, does that mean the step only comes into play at low speed?

Chris Tucker
18-05-2016, 06:23 PM
That boat doesn't have a stepped hull just a cut away chine. The early boats had a habit of chine walking on the deliberately oversized reverse chines if the engine trim was wrong. Cutting away the aft chine stops that happening.

myusernam
19-05-2016, 10:35 AM
is extremeley sensitive to trim a euphanism for poirpoise?

PB
19-05-2016, 01:55 PM
Hmmm. How will it come off the trailer at low tide at tantas?

I had to think long and hard with regards to the trailer design. I looked closely at our friends in the USA to see what they were doing and they do it by running 2 long bunks and no keel support or by running 6 shorter bunks for the 3 flat surfaces but that would mean the trailer would have to be completely submerged and float the boat off, this is not ideal for us in Aus and I like to have the hull supported as wide as I can go on the trailer and also at the keel.
Ive come up with a solution to do both of these and still not have a problem with the steps snagging when backing off. Using this trailer design will be no different to any other of my trailers and will be an absolute dream to load and unload at the ramp.

Chris Tucker
19-05-2016, 02:01 PM
No this wasn't porpoising centre of lift was shifting from chine to bottom if the engine was trimmed wrong. You could happily dial it out with the trim button. But there is certain part of the boating public that always trim all the way out or all the way under. We got sick of saying to people just stab at the button don't hold it down so instead we de-tuned the hull and made it more idiot proof. Personally I like the original boat as it handles more like a cat but it wasn't worth the time spent setting up engines and educating the owners. When push comes to shove anyone should be able to jump on a boat and drive it so we made the necessary changes to make this possible. The advantage of Ali boats is we can do that as we haven't invested in Moulds.

KingyKing
10-06-2016, 12:27 PM
Any updates on this build PB or Chris?

Chris Tucker
10-06-2016, 08:05 PM
Owner was there this week going through fitout details.

Chris Tucker
14-06-2016, 10:21 AM
Tank Coffer Dam and aft console

https://scontent-lax3-1.xx.fbcdn.net/t31.0-8/13415532_1104387972960435_7386656663533145963_o.jp g

console sitting in location

https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-xft1/t31.0-8/13346186_1104388059627093_3102475443906002609_o.jp g

Laying out dash:
https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-xlf1/t31.0-8/13403122_1104388102960422_2651672372502278460_o.jp g

Camhawk88
14-06-2016, 11:38 AM
Looks like it will have an impressive array of screens.
Have you worked out the type and location of transducer yet?

Chris Tucker
14-06-2016, 12:17 PM
From memory one of these (http://www.chsmith.com.au/Products/Furuno-82B-35R-Transducer.html)

PB
14-06-2016, 02:40 PM
Yes as Chris has sheared some pics and mentioned the Client was down from Darwin last week and we went through all the electronics and fit out items. The 82B-35 will be wet faced at the first step and a fearing plate was installed while the hull was upside down. He have spoken to a lot of people both here and some in the US regarding this install and we all agreed on this location. we also have a 1kw Airmar to go in but still unsure of it location at this stage

Lovey80
14-06-2016, 10:02 PM
What are the best transducers to use in Thru-hull applications on ally boats? I notice some are bronze, would this create an issue with corrosion?

scottar
14-06-2016, 10:20 PM
The "best" for lack of a better option are the rubber block units or plastic units. Only issue is they require fairing blocks as nothing in tilted element is made this way. In a tilted element type you are stuck with using a stainless one with an insulator. Bronze is a no no. Another option I have seen used is a lexan faced wet box arrangement - seemed to work alright.

myusernam
14-06-2016, 11:08 PM
is that where the console is going? long way forward where all the up and down happens?

Chris Tucker
15-06-2016, 08:41 AM
Photos make it look like the console is further forward than it is. Boat is 8m long and the steering wheel is right on 4m from the bow, so smack bang in the middle of the boat. we can't move it much further aft as we needed room for the "Battle saddle" (simplified game chair).

http://www.ausfish.com.au/vforum/attachment.php?attachmentid=113364

113364

PB
15-06-2016, 09:59 AM
What are the best transducers to use in Thru-hull applications on ally boats? I notice some are bronze, would this create an issue with corrosion?


We find we get the best results with the genuine rubber housed Furuno transducers wet faced with a fearing block. The Stainless steel Airmar transducers are the second choice, we have had great results with these and never had a problem with corrosion what so ever. You just need to install them correctly.
I have also installed a bronze Airmar at the request of a customer (not on 1 of my boats) and against my advice, It has been in for a 5 years now and no corrosion, It was a nightmare to install but it can be done.

PB
15-06-2016, 10:02 AM
is that where the console is going? long way forward where all the up and down happens?

Its just the angle of the pic, Even if it was a long way forward it would be what the customer wanted, We dont do layouts to our specs its done how the customer wants it, its his money he can have what ever he wants.

PB
07-07-2016, 07:18 PM
Few build update pics.

http://i638.photobucket.com/albums/uu109/Hemo1984_album/IMG_2760_zpspjdkeb0d.jpg (http://s638.photobucket.com/user/Hemo1984_album/media/IMG_2760_zpspjdkeb0d.jpg.html)

http://i638.photobucket.com/albums/uu109/Hemo1984_album/IMG_2761_zpsix1eajw6.jpg (http://s638.photobucket.com/user/Hemo1984_album/media/IMG_2761_zpsix1eajw6.jpg.html)

KingyKing
11-07-2016, 11:59 AM
WOW, this boat is looking fantastic, looking forward to seeing it in the flesh and going for a ride.

chocolatemoose
11-07-2016, 11:20 PM
such an interesting boat and a real unique shape for australia. nice one!. zipwake are a wonderful system :D