Hanging seats off inner gunwales

maccatoga · Post by **maccatoga** » Wed Jul 09, 2008 9:51 am

I am a big bloke about 275 pounds and I worried about hanging the seats off the gunwales. My father attached his seats to blocks he mounted to the side of his canoe?

They are 7/8" wide 3/4" deep, scuppered gunwales and made from Queensland Black Butt a very hard Australian timber.
Is there a risk of splitting the gunwales if I mount the seats to them?

Another concern is how do the seat bolt hole stand up to the years, does water get in and damage the gunwale from these holes?

Lastly do you suggest 1/4" or 3/8" bolts for the seats

Interested in some advise from you guys who have been doing this a while as this is my first canoe and fathers second.

Thanks Guys

canoeblderinmt · Post by **canoeblderinmt** » Wed Jul 09, 2008 7:01 pm

Mac,
I haven't heard of any gunwale failures on this site yet. I did a search on "Seats" and found a couple of links that might be useful. try this: http://www.bearmountainboats.com/phpbb2 ... ight=seats

My thoughts are: Mounting a block (or blocks) amidships could introduce some stresses on the hull that it is not designed for. If you are concerned, what about beefing up the gunwale in the mounting area? Add your block there, where the hull is already stiff, and use the gunwale to help spread any stresses into the hardwood, not the glass/wood sandwich mid hull.

Greg

maccatoga · Post by **maccatoga** » Thu Jul 10, 2008 2:08 am

Thanks Greg

Lots of information in this other threads
I would prefer the gunwale hung seats but my 275 pounds gives me pause for thought.

I suppose if I ate nothing but lettuce leaves for the balance of the southern winter, by spring i could be back under 200 and the gunwale solution would no longer be an issue.
But then again I might lose the will to live before my canoe is completed.

My other concern in how the bolt holes fair over the years?
It will always be stored in side!
But we regularly hit salt water

Do the holes eventually lead to the gunwales failing?

Cheers
Macca

Woodchuck · Post by **Woodchuck** » Thu Jul 10, 2008 8:05 am

I'm your size plus and it's not a problem for the canoe... Remember, you are not sitting on land and every impact or movement is offset by water movement cushioning any blows that could harm your canoe. If you crawled around in you canoe on land, it would be a pretty mess in short order so just keep it in the water, OK...

Rick · Post by **Rick** » Thu Jul 10, 2008 8:57 am

Macca, I tested the ability of the bolt and inwale to carry my 240 pounds on a duplicate section I glued up and mounted in a vise so that I could subject the bolt and inwale to the weight. The single bolt carried my weight without the inwale failing, so I have some confidence that four bolts will be able to stand up to any stresses as the seat is used over time.

Drilling the hole as close as possible to the hull (within limits) will help to prevent the inwale from tearing away from the hull - the further away from the hull the bolt head is, the more leverage there is from weight on the bolt head, twisting at the inwale which could cause failure. The bolt head's force when weight is on it should be primarily down, onto the fiberglass sheathing, and drilling the hole in close will help with that.

Maybe an engineer could explain this better, anyway, good luck.

maccatoga · Post by **maccatoga** » Thu Jul 10, 2008 6:25 pm

It great to hear I can hang teh seast off the gunwales with no problems

Cheers
Macca