Wooden Boat People
By McKenzieDriftBoat.com
First build
Hi everyone, I'm just getting started. I've gathered all the tools, read Fletcher's book about 6 times (so great), and read quite a lot of these posts (also great). I've decided to build a 17x54. Went to the lumber dealer in town, and decided i'm definitely going to use the Hydrotek BS 1088 6mm for sides, and 12mm for floor. I'm going to use Mahogany for the Stem. I'm planning to use Port Orford Cedar for the frames, and was thinking i'd match that with White Oak for the rails/chines. I hope to have the boat for the rest of my life, and while i want it to be the most beautiful boat ever built, I truly want to use materials that will last and be effective. So, first question... Instead of White Oak, anyone ever use Port Orford for rails? It seems like the color would be similar to White Oak, but i wonder about durability as a rail. appreciate any insight you might have.
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Replies to This Discussion
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Permalink Reply by Dusty on
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I need some advice. I'm planning to oil the interior of my boat, and epoxy/fiberglass the outside for strength/protection against impact. I'm about to purchase the 1/2" fir plywood and scarf it. My dilemma is whether to epoxy/fiberglass the interior bottom. While I understand it would increase strength, my concerns are 1. will encapsulating the bottom encourage rot when inevitably a rock is struck and moisture enters. 2. will it create problems when i'm oiling the inside as the years go by. (I suppose wiping excess oil off the interior floor is the answer to that) any thoughts/advice would be appreciated?
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Permalink Reply by David Witton on
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You have summed up the two schools of thought in your post - I'm in agreement with the folks who advise against sealing all surfaces of a piece of wood with glass and epoxy, for the reason you state. However, I have found that it's tough (almost impossible) to feed enough oil into the bottom to keep it looking healthy in the areas without floorboards that take abuse. Mike Baker echoed this in a post sometime last year, and noted that he had begun to use a more durable product on the interior bottom. I don't remember what he was using, but you may be able to find his post.
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Are you saying that the oiled floor is experiencing rot? or just appearance grime, etc?
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Permalink Reply by Phillip Westendorf on
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Dusty,
Your going to want to glass the inside too. The bottom will the be totally encapsulated and give you maximum protection. You need to use some heavier glass on the bottom side. I have two full layers of 6 oz cloth and a third in the front 1/3 with graphite in the last 3-4 coats of epoxy. In five years now just minor scratches on bottom.
I have a single layer of 6 oz on the inside which was applied prior to assembly to the frame. Still looks like new. But I have three removable floor panels sitting on and between frames. They are oiled every 2 years. They take all the beating.
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Permalink Reply by Shawn Baker on
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I'll take a slightly different tack. As David Witton mentioned, there are two schools of thought:
1. Wooden Boat
2. Wood-composite boat.
If it's a wooden boat, you want to oil it, and you also want it to be able to breathe. Water gets in, and water finds its way back out. Dirt and prolonged exposure to water are your enemies--they will lead to rot.
If it's a wood-core composite boat, you want to encapsulate EVERYTHING in not only epoxy, but epoxy/glass. Epoxy by itself is a poor coating. It will micro-crack as the wood flexes and water will get in, but not out. Add glass, and you have a wood core fiberglass boat and generally keep water out--you have to be religious about patching dings that penetrate the glass. Epoxy isn't great under UV, so you need to keep it painted or covered with spar varnish.
Neither is perfect, yet both are very good. Mixing techniques could give you the best of both worlds, or the worst of both worlds.
If you're attaching the floor with screws or bronze nails, you'll be penetrating the glass layer with fasteners and letting water in with no way to see rot. Since you have a ribbed boat, my vote is to let it be a "wood boat" and keep the inside exposed and give it periodic maintenance, cleaning, and oil.
(to be honest, I have a wood-composite boat with ALL wood surfaces except the gunnels coated in epoxy/fiberglass. The 1/2" doug fir floor has 2 layers of 17oz biaxial glass inside and out)
outer glass protects from scratches and minor dings. Inside glass protects from big impacts--as do ribs.
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Thanks for the input. You have a fully glassed/epoxied/varnished boat, but you'd recommend oil? You're getting at the heart of my question, which is to have the floor/sides retain the ability to "off gas" any moisture that enters hoping to minimize the possibility of rot over time. But if i'm forsaking strength in the floor then i gotta think about that. I'm a good oarsman, but it'll be run on places like upper McKenzie and Wild Rogue so i'll no doubt eventually take a solid hit from below. As I'm thinking about it, it would be interesting to know how much strength is added by glassing the top and bottom of the floor vs just the bottom.
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If you have a fully glassed/epoxied/varnished boat, you don't need oil. It won't absorb into the epoxy/varnish.
If you have a ply-on-frame boat that isn't epoxied, then oil is your friend. It will let the wood get wet, but also dry back out. It should delay rot from taking hold both because it provides a thin barrier on the wood, and it also off-gasses.
I didn't want my post to sound like "you should do what I do": I also respect all-wood boats, and hoped to share advice on their care and feeding.
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To the second part of your question:
"it would be interesting to know how much strength is added by glassing the top and bottom of the floor vs just the bottom."
Well, it's actually a LOT! If you have a glass/ply/glass composite, it's really a sandwich panel. The glass are stressed skins, and the plywood is the core. The thicker your plywood, the farther apart your skins are, and the stiffer the panel.
Glass is OK in compression and shear...and it's awesome in tension. Wood is pretty good in shear and tension...and when you spread a force out with glass, it's great in compression, too. It's also very resilient (where glass is brittle).
glass on the outside won't keep a big rock from penetrating your floor. Glass on the inside backs up the plywood and will make it a lot harder for the big rock to penetrate the floor. either way, you're probably doing a repair, but glass on the inside might allow you to finish the trip with only limited leakage and fix it later at home. It also has a weight penalty.
Disclaimer: I don't fish at all, my use will be purely whitewater and camping. I've been WW kayaking for 23 years, rafting for 15 years. Did a lot of stupid things in woodstrip sea kayaks 15 years ago (surfing, rock gardening, bashing barnacle-covered jetties), so I've done some damage and repairs to woodcore boats. This is my first foray into dories. I have not yet holed my dory, but I know eventually I will.
Everything is a compromise!!
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I've concluded that I think it is worth the risk of entrapment/rot to glass the inside of the floor. Between you, Phillip and Dave's input, that's where i've landed. thanks for taking the time to reply, i really appreciate it.
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Dusty,
FYI, late November 2017 I was fishing Steelhead on the Lower AuSable in Michigan. As I was drifting downstream I went to pour a cup of coffee. Before I Had a chance to finish that I hit an unseen deadhead.
The picture tells the result of that "bump". It hit between two frames, as luck would have it the resultant hole was at the water line. Managed to get to shore and add a temporary patch the hole with duct table (don't leave home without it). I'd like to think the glassed side panels, 1/4" cedar strips with 6 oz glass on both sides was what kept the hole from being much worse. Accidents ARE going to happen sooner or later if you use the boat as intended.
This is the finished patch. No varnish yet but two layers of 6 oz glass on outside and one on the inside. I think it's going to last as long as the rest of the boat. Cheap insurance, glass on both sides!
Phil
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