Scuppers, Seats, Yoke, Calculations? Help? Nomad!

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NomadShawn
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Scuppers, Seats, Yoke, Calculations? Help? Nomad!

Post by NomadShawn »

Hey all,
I am getting close to the final stages of my Nomad. I have cut a beautiful board of this Redish Mahogany into one inch strips for gunwales. I am trying to figure out about making the appropriate scuppers and also seat mounting tricks and whatnot. Is there a calculation for a 17' boat? the riders will be about 200lbs each, sometimes packs will be carried, and my sitka spruce yoke is light and strong.

I hope these gunwales work well, does anybody use mahogany? how do I cut scuppers, looking for good techneques and depths and widths for the inwales. I figure I should be able to get the inwales and possiblely outwales done this weekend if all goes well.

Does anybody use routers to cut scuppers, or any other power tools? any feedback is much appreciated, first time boat builder is excited but not wanting to mess up this crucial step.

Thanks
Shawn
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Glen Smith
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Post by Glen Smith »

Not specific to a Nomad, but Ealger has some photos that might help provide you with some clues. Go through the sub-albums listed on the left:
http://s12.photobucket.com/albums/a237/ealger/
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ealger
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Scuppers

Post by ealger »

Shawn,
I like Mahogany for my scuppers. It gets a deep rich color when epoxy is used to seal.
The pictures Glen has referenced shows the use of a straight cutter. I'm changing to a carbide 1/2" spiral with a template guide bushing in the router base. The spiral bit will reduce the tearout in the Mahogany.
Ed...
Ed Alger
NomadShawn
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Post by NomadShawn »

Wow Glen, Ealger has some pretty neat stuff, I think his level is a few steps above mine, but gave me some great ideas, thanks
NomadShawn
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Post by NomadShawn »

ealger, that jig and way of cutting scuppers looks best, now I am debating to use scuppers or not. I have cut my mahogany gunwales all for of them, just deabting whether I should bother with the scuppers
Rick
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Post by Rick »

Is there a calculation for a 17' boat?
IMO, the formula for calculating the location of the seats given in Canoecraft can be misleading... the recommended locations on the plans will probably be good enough for two paddlers of equal weight.

If there's any doubt, C-clamp in some temporary seats made of plywood and test-paddle the canoe that way... this will result in a far more certain seat location than the calculations from the formula. Paddlers sometimes move installed seats around in order to make more room, either for the paddler or for gear, and to correct trim which can affect performance and efficiency.
NomadShawn
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Post by NomadShawn »

Thanks Rick.... do you think I place the yoke in the exact center facing the stern I can get it to be slightly tilted for carrying purposes? I was thinking I need to be an inch or two closer to the stern for the appropriate angle for portaging. Any formula for that one? for the seats I will go by the plan, but there is a support twart not carrying yoke in the plans, so debating what to do.
Thanks
Rick
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Post by Rick »

Shawn, same deal... install the yoke at the balance point temporarily with C-clamps then test to make sure the balance is even with the canoe on your shoulders. Having the canoe front-heavy is worse than the opposite... you'll wear yourself out quickly trying to keep a front-heavy canoe level on the portage.

To find the balance point roughly at first, the C-clamps can be tightened at the midpoint of the inwales, without the yoke in place, then suspended with ropes to see if the canoe hangs level.

The yoke should be installed last so that nothing else can change the balance point. I like to have the yoke facing the stern, so there's a thwart to hang onto to provide some relief from holding on to the gunwales.... good luck!
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ealger
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Scuppers

Post by ealger »

Shawn,
Whether or not to cut scuppers is personal. Your craft will look great without them. The scuppers are traditional and functional as well. It's been pointed out why they're installed.
For me, it's all about the journey. For some, it's getting in the water the fastest way possible.
Your canoe will be with you and your family for a long, long time. If you decide to cut the scuppers, practice on some scrap and cut a dozen or so until you're satisified with your ability to do a decent job. What ever you decide to do, do it safe!
Ed...
Ed Alger
Rick
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Post by Rick »

Whether or not to cut scuppers is personal. Your craft will look great without them. The scuppers are traditional and functional as well. It's been pointed out why they're installed.
For me, it's all about the journey. For some, it's getting in the water the fastest way possible.
This may be true for some, but the reasons for leaving them out I wrote about earlier were not about "getting in the water the fastest way possible".

The reasons for leaving them out has to do with a sheer line that is stronger at the inwale glue joint, lightness, modifications with seating, easier re-varnishing, and better looks.

If scuppers are being considered for "function", allowing water drainage on the portage, there should also be a drainage hole in the decks to allow water to escape there. This is where most rot takes place and drainage when the canoe is upside down will help prevent this. Most canoes don't have this feature added in but for some reason in cedarstrips, scuppers are. If drainage amidships is needed, the undersides of the inwale can be bevelled to allow the water to run off, as I described earlier.

The Huron that I built IMO looks better without scuppers. The inwales are thin and there are no scupper gaps there to break up the smoothly flowing lines. Adding scuppers in a thicker inwale would have taken away from the sleekness in this design.

Hope this helps with understanding the reasons for leaving scuppers out. Saying that the reason for leaving them out is "getting in the water the fastest way possible" is misinterpretation, either inadvertent or deliberate, and too easily dismissive.
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Patricks Dad
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Post by Patricks Dad »

Rick wrote:
Saying that the reason for leaving them out is "getting in the water the fastest way possible" is misinterpretation, either inadvertent or deliberate, and too easily dismissive.
I think Ed's point that
For some, it's getting in the water the fastest way possible.
is a valid statement. I don't think it's a misinterpretation of anything. He didn't attribute his comment to anyone in particular (just "some") so I don't see how he could possibly be misinterpreting anything or anyone.

There are indeed builders who would rather paddle than build or may have a deadline that pushes them to make certain decisions about how they build their craft (scuppers or not, an extra few coats of varnish or not, simple decks or fancy decks, stem bands, etc.). All those tradeoffs are OK and a personal choice. It would be pretty boring if we all built the same boat without deviation from some "gold standard". Scuppers are (among many things) indeed an individual choice and there's nothing inherently wrong with having or not having them (or wanting to get to the water as fast as possible for that matter).

I personally like the looks of them but have seen lots of canoes which look fantastic that don't have them. Some (whoever that guy is), might argue that scuppers are simply approximations to the real thing (those gaps between the inwale and the hull created by the ribs that belong in there all along). :smile
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AlanWS
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Post by AlanWS »

I think the most important reason for or against scuppers is whether you like the way they look. I like them.

But there are engineering reasons as well. If you use solid inwales and outwales, usually they will be thinner and more flexible. If you consider the stiffness of a beam, it's the depth of the beam that makes the most difference. Scuppers allow you to separate the strength-providing continuous parts, making the stiff gunwale hold its shape without the added weight of all the wood in between that adds comparatively little to the strength. The scuppered gunwale also will tend to keep the shape you want because it's bent before affixing the scuppers to the hull, so the slight difference in length helps, reducing the need for thwarts for this purpose.

As I mentioned, these engineering differences are minor, secondary to appearance, but if you are going for the lightest canoe possible they can matter.

As far as removing water goes, I think making a path out of the canoe at the tips of the decks would be more effective. Hull shape (tumblehome) makes a difference here too.
Alan
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