Deck "Drains"

[Pernicious Atavist]

As with some many others. my decks and stems rotted a bit from holding water when turned over. I checked Stelmok's books and he says to use copious amounts of preservative. I have yet to see a canoe with any provision to drain that area.

Anyway, when I replaced my decks, I removed the tips with a Forstner bit, leaving a half-inch, crescent-shaped drain under the stem band. I did not use 'classic' materials to make my repair and rely on appropriate use of epoxy, but still felt the need to add drainage.

Why are there not provisions for drainage if it's a historic problem?

[davelanthier]

Any rot I have seen was caused by moisture from the exterior, not the deck interior ???????????

[pklonowski]

Perhaps because it's not historically accurate as a restoration? I have heard of people installing PVC pipe as drains, but didn't like the way it would look on my cedar strip, so I scrapped that idea. The half-round hole that you describe will not be easy to refinish when the time comes, but perhaps the time won't come along for a longer interval with that feature built in. Hmmmmmm

[Pernicious Atavist]

Yeah, don't see the point of PVC at ALL. Why we don't do it is one thing; why the originals didn't is another.

[martin ferwerda]

Thompson left the stem tips exposed, it probably helped lessen the problem some.

[Howard Caplan]

Not historical but, Bell Canoes on their wood trim boats scallops the decks to allow drainage.
Howard

[davelanthier]

I still don't think interior drainage is an issue. If it was why do the outwale tips rot first? I suggest it is caused from direct exterior moisture when the canoe is stored upside down on the ground or on saw horses. In the case of the saw horse storage moisture will follow the outwales to the lowest point which is the canoe tips. Further, it is not unusual to see a canoe that has been stored leaning against a building with the outwale resting on the ground. The center of the outwale is rotted because of the ground contact but the stems and decks are fine. With any rotted deck I have replaced the exterior is the worst which is where the rot obviously started.

[Rollin thurlow]

There are several manufacturers of canoes that used the Thompson method of deck design which left drainage for the deck are. I have seen no difference in the amount of rot for any of the different designs. As Dave mention just berfore this, the deck areas collect mositure and the drian holes don't really make that much of a difference. Air circulation under and around the deck is really poor and a small hole is not going to make much difference of drying out the wood. Using the proper woods and proper sealing of the wood joints with a flexable bedding compound (but not gluing the joints) will give you a lot more protection than a hole in the deck.

[Pernicious Atavist]

Circulation would certainly be an issue. With the pervasive, year-round humidity we have here, I need to help the boat dry any way I can, short of bringing it in the house! [Which has been suggested. :rolleyes: ]

Thanks for the great and informative discussion, all! :D

[davelanthier]

Don't know why,I just cant leave this one alone. Seems to me the reason spiders love the under side of a deck so much is because it is so nice and "DRY". If you have a ribbed canoe with a little water in it the water will flow along the ribs and run out as soon as the canoe is turned over. With normal use how do you get water under the deck?

[Pernicious Atavist]

That's okay, Dave!

How do I get water under the deck? Well, I get a fair amount inside under sail, and I rinse the boat after every use to remove salt, sand, shells, etc.

[Gil Cramer]

In my experience, the Thompson canoes with the stem extending flush with the deck, and not ending under it, have had less rot than other canoes. As far as stem, deck, and inwale rot caused by the water inside the canoe, I firmly believe that this certainly is the cause.
When a canoe is stored right-side-up, the water inside the canoe has a chance to evaporate. If a canoe is turned upside down before the water has evaporated, all of the water between the planking and the canvas runs to the rails. Because the outwales won't allow it to escape, it runs rather slowly along the outwales to the ends and stays there. It rots the decks, stems, inwales, canvas, and eventually the outwales.
Most people believe that the rot was caused by storing the canoe on the ground. In my opinion, that is NOT the case. The water inside the canoe causes the rot because it simply cannot get away. If the canoe is stored outside, even condensation follows the same path. I can almost always tell a canoe that has been stored upright, because of its lack of tip rot.