Air Tank Repair in a Souris River Canoe

Heaven's to Betsy - whatever will we do???!! My Souris River Canoe has this odd bulge in the bottom of the airtank. It looks like something is wrong!!!! I fear for my safety!!!!! What should I do???? Is it safe to be in this potentially deadly canoe? It's SO scary, I think I'm going to be sick...

Whew! Glad I got my irrational panic and concern over total bull$#@& off my chest. On to the problem of deep concern...

You just can't believe how many people see the bottom of the airtank bubble and how they (usually outfitters) used to freak out. Some lay people still freak out. It's delaminating!!! The term "delaminating" is a HUGE, worn-out buzzword bantied about with abandon mainly in the canoe and crosscountry ski industries, and by a majority of individuals who aren't really sure of how it actually pertains to the item that is supposedly delaminating. But, despite their usual total ignorance, saying "delaminating" really sounds like they know what they are talking about. Come on, say it out loud with determination: Delaminating. Doesn't that feel good? It makes you feel like you are part of a super-secret, canoe repair team. Buzzwords are so much fun!

Well anyway on to the actual problem, what it means, and how to fix it.

This is a Souris River Wilderness 18 that is in the canoe fleet of the US Forest Service out of Ely. The gear guy (don't know the official government acronym) brought in this canoe to me. It had a broken gunwale and two large tears in the hull just below the portside gunwale. In applying all of my forensic canoe analysis skills, I determined that a red trailer hitch (attached to a backing up truck) ripped a large hole in the side and took out the gunwale leaving behind the imprint of a trailer hitch and the safety chain ring welded to said hitch. There was also red paint present at the point of impact which would lead me to conclude that the hitch had red paint on it. My final clue was when the USFS gear guy said that an unknown Forest Service truck backed up into the said canoe, and Sgt. Schulz knew nothing.

Well that was a rather involved, but fairly simply repair so I'm not going into that. Instead, I made some necessary repairs to various stressmarks and moved to the airtanks.

If there is an Achilles heel in a Souris River Canoe, this is it. It is also a very minor deal and pales in comparison to the Achilles heels I could accurately point out in many other kevlar canoes.

What happens here?

Souris River Canoes are made to flex on demand. Nobody else makes a kevlar canoe that can do this repeatedly, day in and day out with no significant damage to the canoe. I repeat, NOBODY. I don't care if you think I'm making this up. The unbridled truth speaks volumes and proudly.

Anyway, the SR hull can flex all over as it needs to except one place- the kevlar glued to the styrofoam that makes the airtank solid. When you see the airtank with a bubble in the bottom portion of it, it is caused by one simple thing: Someone parks the canoe on a rock, log or bump directly below the airtank front (the part you see) and sits, pushes down or applies downward pressure to the hull. The bump pushes upwards and causes the kevlar that has been glued to the foam to peel away from the foam. The kevlar is really strong, the epoxy resin is really stong, the foam is not. You end up with a bubble of varying size at the bottom of the airtank. This is not a big deal. Nothing is falling apart, no critical parts are going to fall off, and I've explained this to several outfitters (you know - supposed canoe and wilderness experts) who still can't figure out what happened to the airtank after renting SR's for years and years. I remain so unimpressed.

If you beat on the canoe over and over and over and over as is the case for most rental canoes and US Forest Service canoes (ie, canoes that get used a lot - not your average privately owned canoes), the kevlar that is bonded to the bottom of the canoe from the airtank, eventually tears open. So, when paddling, water can seep into the tank which means nothing because the tank is full of chunked foam which displaces any meaningful amounts of water, so even if the bottom of the air tank is torn, the canoe will still float fine when capsized. This is the reason that the airtanks exist in the canoe. If you capsize (roll it, bite the big one, land in the cold, cold water) the SR canoe will remain floating so you have something to hold onto as you wait for the Coast Guard to fly that orange and white chopper overhead and pull you out of the drink. No rescue choppers here in the Boundary Waters. You may be on your own so wear your blanketyblank life jacket!

The pain-in-the-neck part of water seeping into the airtanks while using the canoe normally, means that you can end up with a "tail dragger" or a canoe that is heavy in the stern until all the water drains out on the portage thru the built-in drain hole in every airtank of every Souris River Canoe. Tail draggers are canoes out of balance and can be very annoying. Because most canoes rest on the water slightly higher in the bow, all the paddle-dripping water heads to the stern and into the rear air tank. This in itself is a good reason to fix the bulge if you see a tear in the kevlar in the bottom of the canoe. I use epoxy resin and strips of kevlar, but fiberglass will do as well too.

I first was going to just fix the canoe airtank, and then I thought that I should take pictures and explain this process because I hear about about all the unnecessary "shock and awe" that is spread by ignorant outfitters and enemy-territory sales staff who don't even know how their own canoes are built, let alone Souris River Canoes. They sure have a lot to say however.

Click on the picture for a bigger image

1. Because I did not plan on shooting this repair originally, there is no visible bubble at the bottom of this air tank, but it WAS there. I took a sharp knife and cut clean through where the flat kevlar of the tank is bonded to the main canoe hull.
2. This is what the bubble looked like sort of before I cut the fabric. It began where the shadow of my finger points.
3. And this is the foam layer that is underneath the kevlar cover that is bonded to it. See? No magic, just foam. Note the blue tinge on the kevlar flap. That is remnant foam that tore away from the foam layer and is the weak part of this region. Hey, it's foam, whaddya expect?
4. If we had hills in northeastern Minnesota, this would be a hillbilly with a knife. That's a Kershaw Blackout. Very cool and wicked knife. Goofy looking hillbilly. 5. Here, the cool knife is used to poke holes in the foam. By poking little holes in the foam, resin can soak into them and make like little epoxy nails offering a superb mechanical bond to the foam. It's my theory that the rebonded foam will be harder to pull out when the next fat ass plunks down on the bow over a rock/bump/log with abandon. 6. Before we resin it all up, we cut a board to serve as a press. Any ol' board will do as long as it's flat.
7. Here I'm applying resin using the highly specialized technique of dunking my gloved hand in the resin and smearing it all over the foam like a Democrat. (meaning liberally)
8. Still smearing.
9. ...and still smearing.
10. Applying plastic BEFORE putting the board in place.
11. If you don't apply plastic and use the board, you will have a permanent board stuck in your canoe.
12. Hillbilly with a wiener stick. Note the fork. You can cook a hot dog AND a marshmallow at the same time for a real man's s'more. Mmm mmm!
13. Note that the fork is going to go against the leading edge of the front seat.
14. Using the gentle, two-handed bending technique, the sapling is bent to apply firm but fairly gentle pressure to the board which holds down the kevlar flap on th resin-smeared foam.
15. Board holding stick is in place.
16. Next day board is removed and plastic peeled away, wadded up on flor of canoe for proof.
17. Sand the bottom of canoe next to newly re-bonded airtank. Blow away dust like the big bad wolf or use an air compressor like I did.
18. Next I cut some 2" X 7" kevlar strips and wetted them out with my favorite gloved fingers to seal the edge around the bottom of the air tank. I applied a Democratic amount of resin being careful not to have it pool up at the bottom.
And there you have it. Looks difficult, but is not too terrible and an airtank bubble is not the end of the world.
19. It looked pretty much like this the next day. No more water getting in there. 20. This is the stern the canoe. note the little horizontally oriented bubble near the bottom. There was also a crack in this bottom but the delamination was not too big a deal, so I ended up just putting kevlar strips along the bottom section leaving the little bubble intact. It looks a lot like picture 19  


This is the same canoe with the gunwale being replaced. That's a whole bunch of other info, pics and tools to do this job. I did it all at once on this canoe and it took me two days to complete while waiting for resin to cure. I also rebuilt the end caps because the people who portage this canoe (more experts) can't seem to understand that when you go downhill, that bonging noise coming from the stern endcap hitting rock is not a good thing. One does not need a panoramic view of the portage! Carry the canoe level to the terrain and quit dragging the end caps! They're all friggin' pilgrims...

Good luck - not too hard to do and you can't really screw anything up. It's not like a car engine where missing a few bolts might make it blow up and catch fire. It's just a canoe.

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