Building Method & Materials Advice - Power Outrigger
Here’s the boat I built attached. I matched size of the ply to the cedar. My boat weighs about 140 pounds all up and ready to sail. I’m dealing with early onset arthritis which is why I’m building an adult boat now.
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Bill in OttawaNice boat and picture.
It’s a very fun boat - you can be fully trapped and flying when the keelboats around you are sitting with their sails slatting. I’m just not fast enough for it anymore and worry about the time spent swimming wondering how many more attempts I have left to get up on the board before exhaustion. I made the cardinal mistake of building the boat I had always wanted when I was young instead of the boat I needed when it was finished. It’s why I always try to remind people that the building process should recognize that a lot of time passes before the boat is complete - and you may not be the same guy you were when the project started.
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Bill in Ottawa
Looking into it more, I am now very attracted to strip planking. I get the shapes I want outside, and a clean hull inside.
I am going to look into Kiri wood. It is suppose to be less expensive than Western Red Cedar, weight less, and it is renewable. It is suppose to be very rot resistant, and does not have the toxicity issues of WRC. Does anyone have experience with it?
Looking into it more, I am now very attracted to strip planking. I get the shapes I want outside, and a clean hull inside.
I am going to look into Kiri wood. It is suppose to be less expensive than Western Red Cedar, weight less, and it is renewable. It is suppose to be very rot resistant, and does not have the toxicity issues of WRC. Does anyone have experience with it?
I think Kiri and Paulonia(sp?) are the same thing, I’ve used Paulonia for some paddles and it would be fine for a strip built boat, lighter than cedar, not as toxic nor quite as pretty IMO but nice in its own right. I’ve built a lot of wood strippers over the years from lots of different woods but now strip mainly with corecell foam.
Skip
Kiri and Paulownia are the same thing…....I am probably going to use it for my build later this year as well.
Some links which may be useful:
http://www.highpointtimber.com.au/kiri/kiriperformance.html
http://www.paulowniatimber.com.au/marine.php
http://www.bowdidgemarinedesigns.com
http://www.storerboatplans.com/Faq/paulownia.html
Rob
Who sells Paulownia in the U.S.? I understand it grows here.
Looking into it more, I am now very attracted to strip planking. I get the shapes I want outside, and a clean hull inside.
I am going to look into Kiri wood. It is suppose to be less expensive than Western Red Cedar, weight less, and it is renewable. It is suppose to be very rot resistant, and does not have the toxicity issues of WRC. Does anyone have experience with it?
I used bold cypress for my boat (strip planking as well), bought in a local wood store in Houston, TX. It is not as light as WRC, but at the time, it was half the price…
Not sure it is a renewable/sustainable wood, though…
Do you have the US National Forest Department book on woods? It is really a bible that compares the characteristics of hundred of spieces. I found it for free on line many years ago. If you are interested, I will try to locate it again…
Cheers,
Laurent
Do you have the US National Forest Department book on woods? It is really a bible that compares the characteristics of hundred of spieces. I found it for free on line many years ago. If you are interested, I will try to locate it again…
Cheers,
Laurent
Thanks.
I believe I just found a link to different PDF chapters for that book:
http://www.fpl.fs.fed.us/products/publications/several_pubs.php?grouping_id=100&header_id=p
Is that what you are talking about? I will take a look at it.
I doubt I would be willing to go with a heavier wood. WRC is already going to be heavier than foam. If it comes to cost I have lots of family and friends up in Washington state with many WRC trees on their land, and they said I could have them. So I am already thinking about cutting trees and getting them milled. Although that project would be a big learning curve, selecting the correct trees, and drying the timber. Sounds interesting though.
I have been learning how to weld, and I have come to the conclusion that welding aluminum seems to be quite doable without expensive equipment (except a TIG-welder and some argon-gas) or much previous experience. I think aluminum has a lot of advantages over plywood or cederstrip, especially in speed of construction and impact-resistance. Aluminum is easy to cut and shape with normal wood-working tools (carbide tipped), light-weight and strong.
I agree Johannes! Aluminum might be a great material for a motor proa. The impact resistance, speed to build and longevity are great where ultra light weight are not reqired. And it could be a combination of an aluminum hull and deck, with a composite cross structure and ama. And with aluminum, you only paint where you want to paint.
I wouldn’t hand cut anything, though. There are plenty of shops that can laser or waterjet cut everything so that it goes together like a kit.
Planing powerboats are almost always chined—or damned close. Very well suited to aluminum.
Russell Brown’s power proa and Paul Bieker’s commuter cat are both hard chined plywood.
There was a BEAUTIFUL narrow Newick powerboat that was aluminum.
Which material is going to survive a log at 12 knots better?
I love the idea of a power proa. There have been so many successful power cats and to a lesser extent tris. It would be awesome to know more about the different handling characteristics of each.
chris
My father was a welder most his life, and worked on many marine applications. Now I don’t have his experience, but from what I recall welding and designing for aluminum is not necessarily that easy. Aluminum loses up to half it’s strength at the weld (unless you heat treat it), and it has long term fatigue issues, and shows few signs before failing. So that’s all a big consideration for an inexperienced welder. Although clearly you can make it work. There are a lot of nice aluminum boats on the water.
I think for a larger boat, with an experienced welder it could be good. But I do think the weight would be an issue on a smaller craft, despite it being a motor boat. And there is the noise factor. Have you ever been inside an aluminum boat with waves hitting it? Loud.
Luomanen - the problem I am having is finding anyone with experience with power outriggers. I have contacted the designer of the 70’ kayak mothership with some questions, but have not received a reply. But the new owners love the boat, saying it has great efficiency and balance. Here is a picture of it out of the water.
Speaking of powered proas (OK, this actually has nothing to do with this thread), but I just got back from Bermuda, and in the museum they had a nice collection of classic outboards that I thought you all might enjoy seeing.
I think for a larger boat, with an experienced welder it could be good. But I do think the weight would be an issue on a smaller craft, despite it being a motor boat. And there is the noise factor. Have you ever been inside an aluminum boat with waves hitting it? Loud.
True that. I would want somebody with lots of hours welding aluminum to stitch up the hull on my boat.
I wonder what scale aluminum starts looking attractive. Around here a lot of the most badass ocean powerboats are aluminum—often catamarans! Fishing boats on lakes and at sea are both pretty commonly aluminum in all sizes.
I do love the plywood/glass/epoxy though.
Galen,
You can probably guess that I would agree with Chris. In my mind, plywood is god’s gift to boat building. There are so many great things about building with plywood. A couple of the more obscure advantages are the ability to pre-finish inside surfaces so that the the interior finish work is done before the hull is assembled. And it can be such a beautiful, warm interior. Another is how forgiving plywood is from an engineering standpoint. Even before epoxy, lots of boats were incredibly lightly built from plywood without much or any real engineering applied. Lots of those boats are still going strong, too.
Edensaw is selling Okume plywood from a new manufacturer (not Chineese). It has some issues, but is much more affordable than the usual high-grade.
Are you coming to PT anytime soon? If you are really going to build a single outrigger motorboat, I’d love to share my thoughts on your design. Wish I could do it here, but typing drives me nuts.
Regards,
Russell
Hi Russell. Yep, it looks like I am going to build it, although what “it” is is far from clear yet. But I am not in a big rush. I have to finish my teardrop trailor first. And then design the boat completely. Probably at least a year or two before I start building.
I definitely will talk with you about it before I get too far along, so don’t feel pressured to labor at the keyboard. I am just fleshing out what it is I really want right now. Nicole and I are probably going to visit this winter. So I will drop by with some drawings.
Until then, plywood, really? I would not have thought it of you. (That’s a joke because Russell talked me into marine plywood for my trimaran build almost twenty years ago). Offcourse I like plywood also. But I really am concerned about shipping it into this very dry desert and the warping issues I have heard about. But maybe with the 1088 stuff the moisture content is already low and it won’t be a problem.
Here is a recent doodle, a mashup of some classic torpedo stern lobster boat lines into my outrigger motorboat.
Aluminum loses up to half it’s strength at the weld (unless you heat treat it), and it has long term fatigue issues, and shows few signs before failing. So that’s all a big consideration for an inexperienced welder. Although clearly you can make it work. There are a lot of nice aluminum boats on the water.
With aluminum you always design with the “as welded” strength, and it is important to design it so there is enough structural stiffness to avoid fatigue in the plates and stringers within the intended lifetime of the hull. It is important to over-engineer all attachment-points as they are high stress areas. With aluminum it is easy to use high-strength alloy-tubes for global structure, like they do in airplanes and race-cars. I have been sketching on large diameter tubes as stringers/chinebars to give the hull a great global stiffness and ease the stresses on the plates. I just have to figure out how to roll 120 - 150 mm thin walled tubes to the correct shape, at home without expensive equipment.
Think over-sized alu bicycle frames.
The vaka could even be made unsinkable with only the air inside those tubes..
Cheers,
Johannes
With aluminum you always design with the “as welded” strength, and it is important to design it so there is enough structural stiffness to avoid fatigue in the plates and stringers within the intended lifetime of the hull. It is important to over-engineer all attachment-points as they are high stress areas. With aluminum it is easy to use high-strength alloy-tubes for global structure, like they do in airplanes and race-cars. I have been sketching on large diameter tubes as stringers/chinebars to give the hull a great global stiffness and ease the stresses on the plates. I just have to figure out how to roll 120 - 150 mm thin walled tubes to the correct shape, at home without expensive equipment.
Think over-sized alu bicycle frames.
The vaka could even be made unsinkable with only the air inside those tubes..Cheers,
Johannes
That makes sense. My trimaran had big 6066 tube aluminum cross beams that curved over the main hull and also the front beam curved back several feet. Those were a real PITA to bend and get into the right shape by eye. So I bet bending very thin walled tubes is tricky. It seems like I remember someone filling thin walled tubes with sand before bending to keep them from collapsing???
Here is a post I found about it (scroll down to see some aluminum tube successfully done this way).
http://www.garagejournal.com/forum/showthread.php?t=106491