Innovation in Plate Hull Design

[Briz]

After lurking and reading these boating posts for months and months I thought I should at least share something from my end. My first plate boat – a Phil Curran open tiller-steer – was sold 5 years ago as a contribution to our family pool (something which everyone else but me seems to use and yet I always have to clean) - only recently have I finally been given the green light by the Finance Minister to get a 2nd boat built.

After what seemed like an endless search at boat-shows, reading review after review and scouring the trading post for this or that boat – I finally ended up asking (no actually pleading with) an old school friend to design and build a new 5m boat. This guy (Brian) was 3 times national Tunnel-Boat champion and raced boats internationally in Europe and Asia (so he’s no mug in terms of hull design) – anyhow what makes these boats unique (for me at least) is his ability to bring across key principles of modern high-performance hull design into plate - which I’m sure we all agree has historically been constrained by the very material that makes these boats so magnificent (try bending a piece of 3, 4 or 5mm plate into a complex compound curve and not only welding it in place but avoiding woofs and stresses). Having said these boats have a link to races doesn’t make me a rev-head as I’m not looking for a fishing boat that ‘goes like the clappers’. Put simply what I like about this design is the innovative techniques in getting the plate to do things i.e., shapes that normal production plate boats never achieve.

I realise these photos of the unfinished boat are ‘different’ and I post them not to push this particular builder or design - but rather in the interests of sparking some general discussion on innovation in plate hull design (in contrast to our current preoccupation with layout and things above the water line). I imagine they will raise some eyebrows from the platie purists … but then I also seem to remember a winged-keel ruffling a few feathers some years ago. Point being … not all ‘pioneers’ end up face down in the mud with spears in their back!

PS: For those who think I’m totally bonkers or suffering from the long-terms effects of substance abuse as a young fella ... “no it is not his first design using these principles in plate” (rather the most recent of an evolutionary series of boats) and “yes the others have all worked” (so well in fact that none have currently been resold and are still with their original owners). So … let the howls begin …cheers
Briz

[juju]

It sure is different.....

[dnej]

Wow, that sure is different.What are the principles,behind the design.I mean ,why does it work so well
David

[Wahoo]

Briz, look out now, some PPL will think your "FREE" advertiseing on this forum LOL



very intersting, i like the hull shape, where it steps down from the keel and flatens out a little, would that be for planeing at lower RPMs?
keep up the pics, i would like to see this boat as it progresses

cheers

Daz

[Blackened]

G'day

Very intersting for sure, and looks a hell of alot of work.

I can see some parellels with a haines SVDH there,

Dave

[Greg P]

Be a good bay boat. Pretty flat at the back ::)

[Briz]

I'm the owner not the builder & the boat is basically being built as a favour - just wanted to hose down the “Free-advertising” theme. Anyhow as for why it works - I'd be spreading it too thin to try for a decent technical explanation but the way it was described to me initially was about entry angles and the flow after this of water/bubbles towards the transom – there are several components of different hull design that ‘somehow’ work in combination. All a bit of a ‘dark art’ for a mug like me … so I'll ask him for a better explanation next week when I drop in for the weekly progress visit. Happy to keep the pics flowing as the boat progresses - although I'm just as interested in kicking off discussion on plate hull design in general and having a look at what else is happening out there?
cheers
Briz

[krazyfisher]

looks great would like to know more

[blaze]

Ok, I've come back and looked half a dozen times thus far. New desigb is always worth more than a quick glanze. Where are you going to mount the tansducer, seems a little limited in space to mount it on the transom . Design tents to leave options for a through hull maybe.
cheers
blaze

[MyWay]

looks good mate
but i m with Greg it looks like very good for bay chop (2f or somting like that )
i would like to know how will handle 1.5 or 1.2 m sea

can u please tall us bit more about how long .heavy . deadrise , bin any flotation add to it , etc
and where is factory

cheers no_luck

[buhky62]

I agree its definitly an innovation in design allright i also would like to see how it handles a bit of swell especialy a following sea , but please keep up the progress reports it look good ........ :P BOB

[finga]

Yep looks like a lot of extra work to the hull.
That's maybe why the design isn't seen around the traps.
Competition and all that crap you know. The costs have to be kept down as much as possible.
Looks good though. Can you put a picture of the entire length of the hull looking side on please??
Blaze, mate. I reckon there would some real good spots for the transducer near those gussets for the rear steps. I can imagine some nice clean water there. Height to the step might be the problem for mounting the transducer though.
From the front it looks like 3 different hulls will/can come into play depending upon speed. Is this the concept??
Do those huge steps in the hull increase stability at rest or are they slappy wave noise makers at rest??
I for one am very curious about the progress of this boat. Please keep up the reports. :)
Cheers and thanks
Scott :)

[seatime]

Looks good Briz, I like it, nice deep forefoot, variable deadrise, beamy, how will the trailer be set-up. Looks like it'll be weighty, but plane easily, what size donk will push it? more pics please.

cheers
Steve

[adds31]

Looks like its got 2 reverse chines on the hull and would handle bay chop no worries with that fine entry and probably go allright outside too by looking at the pics. Those chines make landings pretty good when your boat gets airtime offshore and helps make your boat stable when at rest. I would imagine you would be able to get her up on the plane at a fairly low speed. Be very interested to hear how it goes and see some on going pics.

Cheers Adds...

[saurian]

Briz , thanks for putting up a thread that is far more interesting than some of the more normal types on here.
Multiple chines I've seen but not that variable bend back end , what a piece of work....In plate.
Now for the real question , does it really work ????
Ta

[Dunco]

Hey Briz, nice hull !!! very busy design. Looks like it could be a dry kind of boat with those reverse chines. When did the project start? My 4.6m plate boat gets started this week and I'll post some photo's. It won't be too far off your design without all the frills. Too late for me to change now. How long did the builder say until finish? Oh and don't worry about D!cks saying your advertising, I know how excited i'm going to be when mine starts taking shape. And when it's finished and i'm over the moon, I think members should be happy to know where they can get good product with detaile photo's of the build. All power to ya 8-). Make sure you keep this post going.

[Briz]

Many thanks for all the responses so far … sorry if I am not as forthcoming in answering your questions as you might expect - but in my game we get severely caned if we shoot from the hip with a response and it is not correct (sort of a learned form of caution/discretion). Anyhow apologies in advance that I only have a couple of concrete answers - but will post more after I speak with Brian.

1. Thanks Blaz in relation to the issue of the transducer mount – to be honest it hasn’t come up in our discussion as there seem to have been so many other decisions to make recently - I should mention the transom/step etc has changed a bit since we flipped it over (will be interested in any suggestions you have when I get some pics later in the week).

2. In terms of other comments/questions such as “clear water” for the transducer (Finga) – I’ll check with Brian as well as Gelsec’s question about the trailer set up.

3. I’m clocking up a pretty long list of questions from many other members (sorry not to list you all) most about the general performance (particularly in swell/rough conditions) - I suppose I could give you a ‘backyard’ explanation of how an earlier version of the design performed when I took it for a test run – but once again it would be better to give you an accurate account of how the multiple hull stages come into play at varying speeds.

BTW the actual boat is right on the 5m length to the transom and will be powered by a 75hp Suzuki 4 stroke that we have already purchased a few weeks ago. I’m assured this is all it needs as the hull design results in a ‘terminal hull speed’ (something which I assume means once the hull reaches it’s optimum HP/speed ratio there’s not much point going above it) … but I’m getting ahead of myself so I’ll double check on this to make sure I’m not speaking out of you know what!. Once again many thanks for all the supportive comments thus far!
cheers
briz

[Deiter]

Looking good Briz, very different to what we normally see. Can't wait to see more pics and hear some of the theories behind the concepts involved. Also, couldn't help but notice, NO POD!

Damo

[GAD]

looks good , would like to see more as it comes along

Greg

[insideout]

like a breath of fresh air seeing new designs come to the table, and anything that can attribute to better fuel burn per ltr,+ comfort is what this industry needs!! Thinking outside the box should be fully encouraged, and i am looking foward to seeing and learning more of this design and more.

[Briz]

As promised I went down today and took a few more pics – difficult to get a true side-on-view given the boat’s position in the shed – included are some shots of the unfinished transom which has changed considerably from the earlier design – aiming to have seats built into the transom either side extending to the hight of the gunnels (only framed up at this stage) as well as a provision for an esky between. We’ve also gone for radius/curves on exposed joints i.e., no sharp corners over the whole boat – not sure it this look/feel’s been done much before?… a lot of work but I’m sure it will be worth it in the end. Only tacked in to place at present … but you get the idea once the joints are fully welded & ground.

Ok … had my talk with designer/builder re: how the hull actually works … ahhhh how much time do you have???? … sometimes a mistake to ask questions about topics people are passionate about – but the short/short-hand version is basically he designed a hull (the easy bit) … then set about working on getting the material to do what he wanted given the design parameters (the hard bit). Seems some production boats work the other way around … “lets build a boat with what the material can do easily”. A slightly ‘longer short-hand version’ (excuse the oxymoron) is the design of this hull (as with any boat) revolves around parameters that are all about compromise. A recurring theme of his seems to be … “the laws of physics never change”, hence the impact of length, beam, deadrise etc. with assistance from chines and lift strakes, running planks, ballast tanks - individually and in combination - have the potential to enhance a hull’s performance … i.e., stability at rest versus in motion, dryness of ride, efficiency, characteristics in flat/chop/swell etc etc (things people on this site know a lot more about than me) – anyhow this boat is basically the end product of playing around with such parameters and getting them to work in sync (and at times separately depending on speed). In short he’s aiming at a hull design that narrows the compromises to a minimum. Downside … yes there’s always one … is that sure you can improve hull performance considerably by creative thinking, but in the end the cost of manufacture increases ( a point made by ‘finga’ earlier in this thread). Which is maybe why alternative designs don’t get a lot of exposure.

In terms of actual tech/specs - this hull equates to an entry deadrise of 50 deg. forming to an effective deadrise of 16 deg. that targets ‘ride effect’ over the full length of the boat (I’m hoping here he means ‘soft-ride’). |By the number of times he mentioned them – it seems the 2 ‘main’ parameters he’s working with is an attempt to reduce the hulls buoyancy at rest (stability) while at the same time reducing effective deadrise at the stern (efficiency). Important to note that another draw back is in this particular combination of hull design is that it’s aimed more at low horsepower (efficiency) over the of high horsepower (speed) due to a predetermined terminal hull speed – hence it’s pointless pointing too much on the back (unless you are into skiing!). That’s a summary straight from the horse’s mouth.
Cheers & more pics to follow!
Briz

[Wahoo]

thanks for the update pics briz, looking good,

Daz

[Shane Dyer]

thats true wahoo i know from experience. It is very unusual but very unique,i would like to see it perform at sea in numerous different conditions,it may well prove its worth as a sea boat but i guess time and tests will tell.Untill then i will be sticking to my proven,tried and tested plain old v-hull.Still a very interesting and informative thread,thanks briz.

[Briz]

thanks daz & shane … i thought along similar lines - then i was taken for a test ride in one of the earlier designs – in my opinion it was the softest rides i’ve had! i’ll keep the updates/pics coming until it’s on the water
cheers
briz

[Kato]

Hi Briz,

Looking forward to seeing how the rest of your build progresses.

I actually purchased the precursor to your hull design from Brian bang on two years before the date you posted this topic! There have been a few changes and it would be interesting to see how they go when compared to the original version. Is the ballast keel setup still implemented to increase stability at rest?

Dave, you certainly aren't the first to make Haines reference! Plenty of naval architects made similar comments!

The step in the behind the forefoot will be good at breaking the surface tension of the water, reducing drag and hopefully increasing fuel economy.

I can definately vouch for the ride of the basic design of this hull, dry and pretty soft in 1.5 - 2ft chop. Stable at rest courtesy of the ballast keel which was integral to the original design.

I did have a few concerns with the structural side of things the way they stood originally. I was looking at implementing proper full length stringers as well as implementing frame positions. Its all well and good to revolutionise aluminium boat building with new shapes and looks, but tried and true methods do need to be followed on some aspects of building!

Anywayz, thought I'd post a link with a few pics of my proto that I built. Just need to put a motor and electronics on the boat and I'm set for the maiden voyage!


http://www.equiaustralia.com.au/photoalbum/bboat/albumhttp://http//www.equiaustralia.com.au/photalbum/bboat/album/slides/dsc02063.jpg

[Smithy]

Certainly is aluminium art work on the nearly completed one. Interesting thread!

[Deiter]

Kato, that has gotta be one of the prettiest tin boats i have ever seen. I bet you became pretty close to your angle grinder after spending so long together. Congrats on possibly THE best finished platey i have seen.

Damo

[Kato]

Thanks fellas,

The depth of creativity and skill amongst some of the plate builders is incredible, makes me look like a complete amateur!!!

There was a fair amount of sanding required on my boat for sure, it was the amount of coving that I got my painters to do that really upped the $$$!!! I've got a list of improvements as long as my arm for next time round, as I said, that was just a prototype to get an idea on how it all went together. A lot of the improvements will be aimed at reducing labour and increase structural integrity, I'll be sure to post here once the next project is up and going :-)