flotation in a grumman

My club has acquired a Grumman tandem canoe, and we need to outfit it with some flotation appropriate for short trips (30 minutes to three hours). The ideal arrangement would allow for a small passenger in the middle (child, dog, small adult). I know about these flotation technologies, and I would be happy to hear about others, or about refinements of these.

(1) Inner tube wedged under the thwart.

(2) Blocks of styrofoam glued together and wedged under the thwart.

(3) A proper canoe flotation bag (preferably nylon-and-urethane, from Voyageur) caged with cord. Exactly how to attach the cord to the gunwales, though? I have a feeling a rivet gun will be involved.


What happened to the flotation in the
end compartments? Usually that will be enough unless you are going to do whitewater or get out on windy, wavy lakes.

I would open the end cells and restore the flotation, rather than adding it elsewhere.

Hudson River
We paddle on the windy, wavy Hudson River at Manhattan. I am looking for something to float the boat high when swamped, not just to keep it two inches above the water.


New Englanders of Old would lace-
strap slabs of foam into the sides. Not cheap, but float bags aren’t cheap either.

There’s a guy in England whose site teaches recovery by tandem teams in heavy lake water. I’ll see if I can find the link.

get some float bags
Definitely don’t mess with styrofoam. It is time consuming to shape and install and awkward to remove after you do. It deteriorates over time and leaves little “crumbs” in the river. It traps moisture against the hull, gets moldy and ugly, and sometimes stinks.

Big truck tire inner tubes are a little better but are still awkward and will preclude a passenger sitting near center.

When all is said and done, you will be happier if you get a good set of end bags. Gaia makes an excellent, lighweight urethane set which will do nicely, and sells for less than $60 a pair: http://www.gaiasports.com/product.php?productid=16324&cat=359&page=1

To secure the bags in the boat you will need some nylon cord of about 3mm diameter. You could just drill holes through the hull just below the gunwales and lace the cord through it. It would be easier to install and remove the lacing (if desired) if you attached some lacing loops to the boat, and that would involve using either small, stainless steel machine screws and nuts or aluminum pop rivets secured with an inexpensive pop rivet gun. Either way, you would again need a drill and bit to make holes in the hull to secure the lacing loops.

I have found that these inexpensive plastic cable “clamps” designed to secure coaxial cable and the like work just fine for the purpose: http://www.acehardwaresuperstore.com/2374-straps/72630.html

You can often find 3mm diameter nylon “accessory cord” at outdoor stores, especially if the cater to rock climbing types. Place your cords running back and forth from gunwale to gunwale about 4" away from each other starting at the central end of the deck plate and extending back toward amidships for 24" (or whatever the length of the bag dictates).

For light use you can probably get by securing the bags with nylon cord tied to the corner loops. A better method would be some type of 1" wide nylon or polypro keeper strap secured at one end to an attachment under the deck plate, running lengthwise down the length of the bag, and with the other end secured to an anchor attached to the bottom of the canoe along the center line where the inflated bag ends.

Put it in drydock.
End of problem.

Here’s a link to a video showing
different rescues out on a windy, wavy loch. Be sure to pick up and paste the entire link.


It;s bead block that absorbs water and
comes apart in little bits. Styrofoam isn’t wonderfully durable, either, but if kept out of the sun, it will not absorb water into its interior. Glued up minicell would be better, but more expensive.