Lap repair guide

txcaptdan · Post by **txcaptdan** » Tue Jan 25, 2011 9:51 am

Several members have asked about repairing laps on their boats, so here is how I repaired the laps at the starboard stern of my 20' Cruisers Inc.

Initial inspection showed a hole in the lowest lap and rot in the ends of several others. I sanded all laps to expose puttied over screw heads.

I decided to replace all laps above hole. I wanted to cut back far enough to have two ribs attached to new laps. The lowers worked out so that the 4" scarf would be right over rib. Make sure to pay attention to were screws came out and to save all. there are screws at ribs and nuts and bolts between ribs to hold laps together.

By txcaptdan at 2011-01-25

This shows how the laps fit together, so it takes some sanding on replacement pieces to replicate shapes of the old laps removed. Try and save as much of the removed laps for patterns.

By txcaptdan at 2011-01-25

By txcaptdan at 2011-01-25

I then drew on the existing plank edges the scarf area, 4" back and used a belt sander to grind back the scarf. I had a local woodworker make me the replacement laps mainly because the thickness is not a standard size and we planed some plywood to match thickness. I the shaped each lap to match the one removed and dry fitted each until they fit.

By txcaptdan at 2011-01-25

By txcaptdan at 2011-01-25

After dry fitting I started at the bottom and pre-drilled holes for rib and transom attach the added epoxy to laps and 5200 to seams and transom as I went up. I drilled and attached silicon bronze nuts and bolts to each following lap as I went up.

By txcaptdan at 2011-01-25

After allowing all to set up and checked tightness on all hardware I did a rough sand to level all out. I then used a filler, Formula 27 to fill screw holes and gaps left from scarfs. I sanded and filled several times, you can sand this filler before it completely sets up much easier, then primed.

By txcaptdan at 2011-01-25

By txcaptdan at 2011-01-25

Hope this helps you tackle your project. These boats are just pieces bolted together and any part can be disassembled and repaired or replaced. Use new silicon bronze for hardware and make sure everything is as clean upon reassemble.

txcaptdan · Post by **txcaptdan** » Tue Jan 25, 2011 9:54 am

As you can see the repair worked out beautiful

By txcaptdan at 2011-01-11

JALL · Post by **JALL** » Tue Jan 25, 2011 3:28 pm

Great step by step and pics. THANK YOU

Torchie · Post by **Torchie** » Wed Jan 26, 2011 8:25 am

Great tutorial.
The pics sure help to make the steps involved much clearer.
I am getting ready to steam bend about a dozen replacement ribs for my Offshore. I will post later and let everyone know how it went.
Karl.

carsonphoto · Post by **carsonphoto** » Sat Jan 29, 2011 8:56 am

That's got to be the best step by step I've ever seen....Very easy to follow and great pictures...THANKS!

THE LAKE · Post by **THE LAKE** » Sat Jan 29, 2011 10:19 am

Dan
Did you take any photos of the removal and reassembly of the motor well area ? I notice in the photos where you began to replace the lapstrake sections that the well is missing. Would appreciate seeing that area since I will need to do some work to mine this spring.

Brian

txcaptdan · Post by **txcaptdan** » Sat Jan 29, 2011 5:18 pm

Brian,
I will look in my photos, but I am pretty sure I disassembled the splash well before taking photos. If you carefully disassemble any parts of these boats any piece can be replicated or refinished. I was able to reuse all of my well except the floor of the well. I used the rotted original as a pattern and remade from a thicker piece of marine ply so that it would hold wait stepping through from the swim deck. I may have some pictures as it was reassembled.

Dan

txcaptdan · Post by **txcaptdan** » Sat Jan 29, 2011 5:29 pm

Brian,

There are actually some shots of splash well in my post

http://www.thompsondockside.com/views/v ... c&start=15

I will look for some more.

Dan

PeterZ · Post by **PeterZ** » Sat Feb 05, 2011 2:19 pm

Dan

Great photos, thanks. And congradulations to a job well done, she looks great!

I always had a question about scarfing. I see in Dananberg's restoration boat he talks about removing planks entirely from the boat and scarfing on a bench. Then I later read (probably in Woodenboat) about having the scarf of some ration of length of joint to thickness of plank, etc. Is all this really needed? The belt sander methods seems to work pretty well, and without having to remove the plank. Also I was wondering how you cover up the line in the scarf between the old and new plank. You use some kind of feathering compound. Does that stuff crack as the boat flexes?

Again, nice job.

txcaptdan · Post by **txcaptdan** » Sat Feb 05, 2011 8:39 pm

Peter, I used Formula 27 a marine bondo type filler that I have used extensively on several different hulls with very good results. I think West Marine sells it under their name also. I am doing some refinishing on this hull right now and cannot find any evidence of the repairs. It works well for filling and fairing.

brian62 · Post by **brian62** » Tue Feb 15, 2011 10:44 am

Txcaptdan,thankyou very much for your time and effort into posting this info and pics.This will help me out a great deal.I had to take some time away from working on my boat but i plan on jumping back on some repair work with in a few days . I have the exact same repair to do as you did.Thanks again Brian J

Darryl Siss · Post by **Darryl Siss** » Thu Mar 01, 2012 2:31 pm

I know I am replying to an old post but hoping to get some input. I only have to replace a couple of strakes. Your pictures and explanation are great but I am unclear on one step. When you talk about scarfing, are you overlapping the new insert on the side (not referring to overlap top and bottom) by 4 inches and, if so, how do you taper wood for overlap - is the new piece tapered in back or the part that is left or both? Hope that question makes sense.

Torchie · Post by **Torchie** » Thu Mar 01, 2012 2:53 pm

When scarfing wood both pieces are tapered. If you look at some of the posted pics you can see where the old laps have been tapered, the new ones will look the same on the back side.
Average ratio for scarfing seems to be about 8-1. For every inch of board thickness you woud have 1 inch of length. So for a lap about 1/2 inch thick you would overlap 4 inches.
You can use a belt sander or a plane to make the taper. The harder one of the two pieces will be the one still attached to the boat due to lapstrakes overlapping each other. May have to use a small fine tooth hand saw to get behind the upper strake.
Once bonded and screwed this joint is extremely strong.
Take your time and have fun.
Hope this helps.
Karl.

Torchie · Post by **Torchie** » Thu Mar 01, 2012 2:56 pm

P.s.
What I meant to say is that with a ratio of 8-1 for every inch of board thickness you would have eight inches of overlap.
Sorry for the confusion.
Karl.

Darryl Siss · Post by **Darryl Siss** » Fri Mar 02, 2012 12:23 pm

Big help. pictures are great. Don't think I could have tackled without them.

Lap repair guide

Lap repair guide

lap repair guide