Old Grumman 15 footer with slots in the gunnels

Hi All, long time lurker, first time posting.

I just bought a Grumman 15 ft canoe, serial number makes me think it was built in the early ‘60s.
I’ve handled a bunch of Grumman canoes but this one is different. It has the brackets for a sailing kit, which is cool.
What has me scratching my head is the slots in the gunnels where the center thwart should be. (6 slots on each side, each slot about 1/2 in long) Anyone know the intended use?I’ll try to attach some pics but that’s a tall order for an old guy)
Looking at the Marathon website, I can order a new thwart but there aren’t any measurements included on their diagrams. Can anyone help me figure out which one I need?
I really appreciate any feedback! Thanks!

Mine has those too and I think that was where the lee board bar attached. There was a lee board on both sides connected by a bar that went there.

1 Like

Due to the shape of the aluminum inwale (inside lip of the gunwale) then when you tip the canoe on its side to drain accumlated water, it is much easier to drain than if you had to turn whole thing completely over. You see the same kind of slots in older wood-canvas canoes.


That’s a cool canoe. I’ve never seen scuppered gunwales on an aluminum boat.

If you want a Grumman/Marathon replacement thwart I suggest that you measure the boat’s width and write down the serial number and give them a call. If all you need is a thwart that fits it would be easy to buy a wood thwart and cut it to length edscanoe.com is one good source) or just use a piece of scrap wood. If you live near SW MI I have a thwart that I could give you.

1 Like

Thanks, you guys are awesome. I’ve had hands on a bunch of Grumman boats but the only one I recall with the sailing rig was a big square stern. Many many years ago but o seem to recall the keel dropping in from one side.

The scupper thought is brilliant. I live in south Missouri and we made beer and girl chasing money when we were kids hauling boats for the liveries on Current, Meramec, Jacks Fork, etc. Lots and lots of them. We always had to go back down the line to give one last flip before we loaded them to get that last bit of gravel and water out.

That missing center thwart causes real brain-lock. When I bought the boat, i had a hand to help load it in the pickup. When I got home, I pulled it off in the yard; muscle memory kicked in when I went to pick it up to carry it and I just stood there looking at it trying to figure out how I was gonna get it over my head without a place to catch ahold of it. I stood there slack jawed longer than I want to admit.
I appreciate the generous offer of a freebie but I think I’ll do some measuring and give Marathon a call. I’ll let you know how I end up. Thanks again to all.

1 Like

Years ago I had an early '60s Grumman rigged for sailing. It was an 18 footer (not a square stern) with a large aluminum rudder and center mounted leeboards like these:

It was scary fast … emphasis “scary”.

1 Like

Thanks for the photo. If an 18 footer is scary I imagine a 15 would be scary +. I’d probably give it a try (with a tender) but those rigs have to be scarce.
Btw, looking at the pricing on these boats from Marathon is scary too. I gave 300 bucks for this one—one little dent that will tease out and old paint in the floor but good to go as is. I see 17” footers all the time for $400 to $500.

There were three listed on EBay when I looked the other day after reading the post. Couple of sail kits and one fully rigged canoe.