Wooden Boat People
By McKenzieDriftBoat.com
an older tatman needs a new shoe....should I screw it, nail it, or glue it
hello wooden boat people. As my first post let me start by saying thank you, thank you, thank you for all the help your pasts posts have been. I met a few of you at the boat show a couple weeks ago (I'm in eugene), you'll remember me as the guy with the two akitas.
I recently brought home a Tatman 16x48 built in the mid 80's that needs a new shoe (was uhmw), new outer chines, and new finish. All in all it's in decent shape aside from the old varnish. If the uhmw hadn't been total crap I'd have been willing to take it straight to the river but alas I must wait a while longer before I'm once again at the oars. This is my second boat, I bought my first one back in the early 80's promptly after getting my drivers license. It was in rough shape but my dad (also long time fan of these boats) helped be restore that one and taught me how to navigate the mckenzie. I foolishly sold that boat after getting married. She's gone now so I've been pondering relying on Roger's book to build my own boat someday but I'm very happy to get back into double enders by restoring this one. Old boats have so many stories to tell those who know how to listen so by restoring this boat I'm learning much more than I'd learn by building one, knowledge that will help me build a better boat someday. The stories y'all have been sharing about your own boats has also been a great help, thanks again to Randy for hosting this forum and the rest of y'all for putting it to such good use.
Most of my questions have already been asked and well answered. I had thought uhmw was considered the ultimate solution so I promptly went and purchased a sheet to replace the failed piece on this boat, that was before I found this forum. As a former engineer I took short notice of the thermal expansion issue and realized that this is why the shoe of my boat was in such horrid condition (and why the screws were all screwed up ... pointing in ever direction and some starting to pull out of enlarged holes). The uhmw was also very dry and brittle .... uv degradation I presume. Chine and bow cap were uhmw too, also total garbage. Learning from y'all I promptly returned the uhmw and started down the ply/glass path. As a builder/carpenter and former design engineer I had to take the time to ponder variations on the general approach so I looked at using kevlar, dynel, a very stiff flooring underlayment I've used called superply, normal a/c ply, coat-it, etc. I found that a sheet of 1/4" marine ply in fir is locally made (Roseburg Lumber products) and readily available from any local lumber yard for about $45 a sheet. Yes that seems like a lot but compared to superply and other solutions I looked at trying to keep the cost down I concluded that I would only be able to save maybe half of that, so $20 at most...which is far less than the value of my time I'd spent looking into this and given the potential problems of a failed shoe I happily stopped the analysis, brought home a sheet of 1/4" fir marine ply, and am now eagerly waiting for the arrival of my order of epoxy, triaxial cloth, etc from jamestown.
I'd like to ask how y'all attach a ply shoe. I've seen references to screwing it down but my first next step is to plug all the old screw holes and seal up the bottom with a good coat of epoxy. I don't like the idea of going through all of that effort to seal up the bottom and then putting more screw holes in it (even if sealed with polysulfide). Have any of you glued down the ply (after sealing the side against the bottom with epoxy)? I presume there's an adhesive that would work well for this application but I'm also guessing that the West epoxy works very well as an adhesive so I was thinking I'd just use that. I'll have some effort rigging up a set of clamps to hold the ply in place but I think it's doable. I also thought of using short nails to hold it down but that takes me back to the issue of putting holes through the epoxy that's sealing the bottom. I understand that screws would make it easier to remove the shoe in the future but I'm hoping to avoid any need to remove it for a very long time and a power planer would chew it up fairly quickly. I was also pondering a layer of glass between the shoe and bottom for more strength and to also make it easier to id the layers when it came time to grind into the shoe for repairs and I want to avoid grinding too deep, or maybe just put some colorant in the epoxy between shoe and bottom as a better visual indicator.
As you can tell I tend toward the verbose. I'd love to talk about my boat project more but maybe this is enough for now. thank you all again for the wonderful help you've already been.
Views: 841
Replies to This Discussion
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Permalink Reply by Vance Wonser on
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Got pics? :-)
I'm a newbie with lots of questions, no answers, & a 16' Don Hill that I want to rebuild to get on the water.
I enjoy following others projects so I don't have to "reinvent" the wheel.
My Hill also had UHMW on the bottom before I got it (had already been removed). I intend to glass the bottom. Not sure on the sides. Hadn't even heard of plywood shoes until they came up on here about month or 6 weeks ago, but am now figuring on installing one when the time comes.
Welcome & I will be watching your project with great interest!
BY the way, I moved to Alaska in '88 but grew up (well got older anyway) in Klamath Falls. Used to haul logs to Roesburg Lmbr in Roseburg.
What source are you using for materials? I'm trying to decide who to order from.
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Permalink Reply by Rick Newman on
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Jeff, I think Dave Zelinski has the right idea for fastening. Screw it down, put a polysulfide shot on each screw as it goes in and oil the shoe. His track record and the ease of possible repair seems like a great idea. I'm sure there are other options but I vote for Dave's.
Rick N
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Permalink Reply by Brian King on
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Back in 1985 when I build my first 14 foot drift boat I found this guy in Portland, Oregon who sold skid shoes. It was a 1\4" piece of 4' x 10' marine plywood with a piece of 1\8" UHMW glued to it. My boat rotted out and I took it apart to burn it and that skid shoe could have been used again on my new one if I hadn't had to almost tear it off my old boat. Wish I could find another sheet of that stuff. It was the best of both worlds, a very slick bottom and no need to worry about thermal expansion.
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Permalink Reply by Dave Z on
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Jeff,
I have made several plywood-shoe-d boats and this is how I do it these days:
1. On a new boat with a solid, good bottom, oil the heck out of it. Turp/ boiled Linseed oil (BLO)/pine tar. (50/50 mix, put pine tar in to taste, (not really) for a gallon mix of turp/BLO, i use about half to quart of it.
2. Oil shoe inside face. (the face that meets your boat bottom)
3. Beeswax. heat it up until it is liquid. (im a beekeep, so endless supply of it). I previously did use Sikaflex on 5200 on each screw. I doubt there is an advantage at this point.
4. Dip each screw in the wax or sika. I use #8x1-1/4" Si bronze screws. hamilton marine or jamestown- check prices at both)
5. Screws about 5-6" apart all the way around and on the frames.
6. chine cap over the shoe edges.
Keep it dry. Off the river, be vigilant to keep the drain plug out ( and the boat in dry storage. I have all mine stashed away in a barn that gets some cross ventilation.
I flipped one of my boats recently with a wood shoe to check the damage from a week long low water float. You'd be suprised how little it is dinged up. No gouges through the first plies. More importantly, no internal floor impact cracks. I had the shoe off of one of the boats just to see what it looked like while I replaced a chine cap on one side. Looked good. slapped it with some oil and re-used the shoe. I probably have some pictures somewhere.
Now go search the "where do I put my drain plug" post(s).
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Permalink Reply by Mike Baker on
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I have a friend who has a very old boat that had a plywood shoe attached with contact cement. Boat was used hard and neve de-lammed. Not sure I would actually go that route but food for thought. If I were to do a ply shoe I think I would epoxy the boat bottom just for peace of mind protection, I would not epoxy the shoe to the boat just coat the boat. I think I would put it over the chine caps as well (like they do with UHMW). Since the shoe is sacrificial might as well protect the bottom of the chine too.
Mike
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Screw it on. What I'd do it fill the old holes with epoxy and additives after cleaning them out and making sure they're really dry. Then coat the bottom with epoxy. Coat the shoe also with epoxy and I like to use barrier coat additive then on the final epoxy coat, add some graphite to that. Countersink SS flathead screws just below the surface...I like to bed my fasteners in Dolphinite...it's old school but it works and especially when you want to be able to remove the screws or bolts later, it's the proper stuff.
Below is a link to a Hill boat I did what you are looking at with a year or two back. The owner has been floating the Klickitat for two summers and that is a pretty rocky go...it's holding up fine for him.
I am not sure about the Google + albums web interface and how it works for everyone, but there were long captions with every photo when I had this album on the Google Web Albums site that got revised recently into Google +..Hope it still works ok.
https://plus.google.com/photos/112899774170781374478/albums/5601378...
Don Hanson
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Ok, I see that I had the settings not right in this new Google+ Photo program that they substituted for the old Google Albums program. So I think I have it so anyone can click on that link and find the pics of that project, and the shoe install I did also. There are only a few specific photos of the shoe but there is a pretty good caption with it.
I just read Mike's reply. He describes it well, used some different stuff, but the basic idea is the same. And NOTE!....You should put something into each hole along with the dang fastener! Otherwise, the water will follow down the screw or bolt, right into the hole, then the hole stays wet all the time....the screw will rust or corrode, the wood around it will rot...It will. What I do is squeeze out whatever compound I am going to bed the screws in on a piece of scrap....Then each screw is dabbed into the 'goo' and then run into it's pre-drilled hole...
You can see, if you get on my Google page and see the Don Hill boat....you can see exactly what happens to screws that are put in "dry" with no bedding. The old Oregon builders, they seldom did use any bedding compound...and the boats show it...I had to replace all the gunnel lags on that boat...the fasteners were galvanized, but a lot were rusty anyhow...
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Don, it's working now.
Thanks
Rick N
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thanks for the info/pics. Your approach is a bit different from what I thought other folks were doing for a glassed ply shoe, it's always good to see another approach. I was planning on attaching the ply first and then covering it (and rest of bottom) with the tri-axial cloth and adding graphite in the final flow coats. The boat I'm working on also has rusted screws throughout and I've been pondering replacing them all, or at least those connecting the bottom to the ribs. Like I said above, I'm still worried about moisture working into the screw holes even if sealed and causing long term problems which is why I'm wondering about relying on an adhesive (maybe just the epoxy resin) to attach the shoe so that the 1/4" ply becomes just another layer in a monolithic composite made with layers of glass and plywood.
I'm generally in full agreement with Dave Z that oil is the way to go for the rest of the boat, but not for the shoe...at least not around here (western oregon). The boat I bought when I was 16 had a plain plywood shoe with boat paint. It worked for me for 10 years so I know it's doable and the much lower cost is attractive. Here's a pic I recently found of me and my dad launching into the McKenzie in the early 80's shortly after refinishing it, that's me at the oars.
Part of the reason I ended up getting rid of this boat 10 years later was that I couldn't get my wife to go out with me anymore after a minor bit of excitement from getting stuck on a rock. Actually, the excitement came after I finally got us unstuck and we entered the next section of fast water which ran into a rock wall and took an immediate left turn facing the wrong direction. With lots of swearing I managed to get the boat spun around just in time to get in one mighty heave of the oars that managed to keep us off the wall but we both had to hit the floor (me by bending over backwards with my ass on the rope seat and my head on the rear deck with my hands over my head pulling the oars in) as we went under/through a section of low hanging branches. In the end all was fine but a hard slick bottom would have helped avoid getting stuck and the subsequent near disaster.
I'm also wanting a hard bottom to deal with the boat lauches we have around here, a fair number of which do not allow the trailer to get into the water (or at least you'll need a 4x4 and winch to get back out again). Taking the boat off the trailer on dry land and dragging it to the river is the only real option.
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I think you're mistaken then, when you call your proposed added ply layer a "shoe"... You are actually talking about adding another layer to the bottom. A shoe, or more often called a "rock shoe" maybe, that is a wear item, a throw away layer that is meant to be easily replaceable when it gets worn by dragging over rocks or whatever.
For a time there, the plastic crap was thought to be the right stuff for this purpose, but we kinda learned different as these boat aged...Those plastic rock shoes caused a lot of grief...though they did do a good job protecting and sliding off rocks....they just didn't work that well with wood and got real brittle.
So what you want is to seal up your bottom really well. Then, you can put on the Rock Shoe, making sure you seal up the screws as you mount it and later on, if that gets beat up, you can toss it and mount a fresh one...They are meant to save you the work of having to replace the whole bottom of your boat.. If you bond another layer into the hull, you will have a stronger bottom, but it will still be taking a beating on the bottom and the ramps and the trailer, and eventually it will wear out.
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thanks for the input. I'm happy to call it something other than a shoe, but the idea is still to have a bottom that's easy to repair, even in the field. In fact, I'm planning on attending to the bottom as part of my annual maintenance along with oiling the wood by patching any damage with epoxy or Coat-It, should be fairly simple.
One worry I've had about my proposal is that a crack could propagate from one sheet of ply into the other if they are fully glued together with epoxy. Since I posted my question I started pulling the chines and discovered that 3M's 5200 was used to bed the chines. I also discovered that the screws were rotten so they weren't doing anything except promoting rot, reinforcing my worries about screws. I had to grind the chines off to avoid damaging the plywood. This stuff is obviously a quality adhesive but what I like the most about it is the rubbery quality it retains which should eliminate crack propagation so I've decided that I'm going to use it to attach the 1/4 ply (after sealing with epoxy) and then build up the glass on top of that.
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Permalink Reply by AJ DeRosa on
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Jeff,
I believe you can build a shoe that will be slick and tough AND one that you can screw on as was the case with the old school wooden sacraficial shoe. Of all the ways to do things to a wooden drift boat this bottom thing is the most interesting because it has been attacked from so many different angles. So here's my 25cent contribution. The rest of you guys please have at it, I have not done this so all critiques are fair and welcome.
This is a down and dirty but tough shoe. One 8' sheet of 1/4" marine fir or mahagony. Cut to shape over the impact area of your bottom, that would be from the second frame back to somewhere near frame 5. Cover one side and/or both with glass and epoxy. I'd use 20+oz triaxial cloth because it has yet to fail me, for the underside. Could put lighter glass on the backside or not. Glassed on one side or both will produce a tough piece that will be slick, not as slick as UHMW, but totally stable to temperature differences, which UHMW is not. If you choose to glass just one side then pour the oil to the other side. This piece can now be mounted with screws and works like the traditional sacraficial shoe but has the slickness of a full glass/epoxy bottom. Use the screw technique that Don Hansen suggests, use some sort of gugempucky on your screws. This could be screwed to an oiled bottom. This is not as good as a full blown properly applied glass/epoxy bottom but the idea was about a shoe. This is only my opinion. I have never done this but have considered it for a while now. For what it's worth, there's another idea on the frame boat bottom solution.
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