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Permalink Reply by Randy Dersham on January 22, 2011 at 1:03pm

Peter I think you have it exactly right.

Definitely remove the glassed over chine batten and replace with a new oak chine batten to cover the new end grain.  Bed it well rather than glass over.  

The one thing you didn't talk about was final finish for the bottom.  David Z will tell you to oil it. That has worked well for builders for many years because it can keep the bottom reasonably soft and pliable and helps it last longer. It is the same idea as leaving the ends of your oars unfinished and keeping them soaked in oil.

 

I prefer to soak coat the bottom with Epoxy.  Use a very thin penetrating epoxy so it can get as deep as possible into the first layer of the plywood.  The purpose isn't to make it last any longer, because it wont, but to make the bottom more slick. This method could actually trap water which could make the shoe rot out. The epoxy will eventually tear out as you continue to scrape over rocks.  The purpose is to make the bottom less sticky.  Here in the West sticking on a granite or lava rock can cause a high side. Many of us have made a mistake reading the river, ride up on a rock, then in that Oh-No second when we know we could be getting into trouble we pray that we slide off of that rock rather than stick.  A slick bottom is more safe. That is why the UHMW is still so popular.  

 

So, I recommend that you match the bottom finish of your shoe to your most common river conditions.  Sandy and round river rock bottoms you can use the oil and your shoe is likely to last longer because the oil won't trap moisture.  Rivers with sharp showing rocks that you might run up on lean you toward the most slick bottom you can put on the boat.  Epoxy impregnating that shoe will be slicker and a little more safe on those rivers. 

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Permalink Reply by Peter Foster on January 22, 2011 at 6:34pm

Randy,

I really appreciate this website. I run the clackamas, wilson, sandy, Lewis,  Dechutes,- Oregon & SW Washington western rivers.   I've felt the sticking even on rounded river rocks with the painted epoxy bottom and it is not a safe feeling. I'll go for the slick option anytime.  To use (2) 4 x 8 sheets I need to make joints- any recommendations- 45 degree beveled butt joint?  What do you think of 3/8" Ext. A/C fir plywood as a shoe"

 

Randy, Please clarify "The purpose it's to make it last any longer, because it wont. This method could actually trap water which could make the shoe rot out."

 

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Permalink Reply by Randy Dersham on January 22, 2011 at 8:33pm

ah, that last bit was a brain fart.  " The purpose isn't to make it (the shoe) last any longer, because it wont.  This method (the epoxy soaked first layer) could actually trap water which could make the shoe rot out."

 

My point is that epoxy on wood that does not include cloth will get knocked off or "knifed" by a rock allowing water in under the epoxy.  Trapping that water will cause rot; however, the shoe is already made to replace. So, it is my opinion that in our water here in the West the slicker surface is more safe than the longer lasting oil. 

 

I would not use the A/C plywood because the C side causes problems. If it is on the outside the bottom won't be smooth and the C side will be prone to fail.  If the C side is toward the boat bottom the C side's imperfect finish will act like voids that help the plywood fail and trap water.  

 

You don't have to put a second bottom on the entire boat.  One option would be to use one 8ft piece and cover only the center.  If you want to cover the entire bottom I recommend that you scarf the two sheets before you attach them to the bottom with a traditional 12:1 scarf.  Search the forum for "scarf" and you will find many posts on how to make that joint.  It is the same principle as your recommended 45 deg angle but has a much steeper angle with a feather edge that makes a joint almost as strong as the plywood.  

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Permalink Reply by Randy Dersham on January 22, 2011 at 8:46pm

When you screw down the plywood shoe use 3M 101 or other similar polysulfide bedding compound.  If you use the 5200 as I recommend with UHMW it will make a permanent wood to wood bond between the pieces and the shoe will be very hard to remove without causing damage.

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Permalink Reply by Peter Foster on January 23, 2011 at 12:53am

Thanks for the help Randy. I'll have to do a little more research for best low cost material. those +/-8" wide scarfs use up a lot of plywood.   I'll  need two  4 x 8 to cover the bottom or one 5 x 10.   boat has  4'-4" x 12'-2" dimensions along the bottom.  Anyone know a good source for  low cost material .  I'm  looking for  3/8" ext. fir A/B  plywood in 4 x8 or 5 x 10 or same in marine grade. Portland, Or  does not have a lot of sources.  Crosscut hardwoods has 4 x 8 x 3/8 in hydrodtec but is $77 a sheet, and that is for a thow a way shoe material.  Parr Lumber has 3/8"  x 4 x 8 fir  Marine for $60 a sheet but is only 3 ply. I think so far the Parr Lumber is the lowest cost option.

Anybody know any local (Portland Oregon) sources. I've been on the net for three sights searching and most is shipped from the east coast  and runs about$ 150 just for the shipping. homestead has $46 dollar 3/8 x 4 x 8 fir but again the crating & shipping is killing me- $300.

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Permalink Reply by Lawrence E. Long on January 23, 2011 at 5:02am

Peter:  They do a lot of boatbuilding up in Port Townson WA-(spelling might be off)- much closer than the east coast.

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Permalink Reply by Mike Baker on January 23, 2011 at 6:59am

Peter,

I live in Central Oregon and all of my Fir marine plywood comes from the valley. Any good building supply (not a box store) place should be able to order it for you with one day turn around. 3/8 fir should not cost more than about $40 per sheet. Mr. Plywood has very good prices.

Mike

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Permalink Reply by Rick Newman on January 23, 2011 at 8:24am

Peter,  believe me I understand that costs are important, I have been scrounging for a long time to buy epoxy and finish, Perhaps considering what the shoe will protect and what it costs in time and materials to repair the damage caused by even one incident.  It looks like Mike Baker might have a good source.

 

Good luck on your restoration.

 

Rick Newman

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