Wooden Boat People

By McKenzieDriftBoat.com

Screw pattern- for epoxy bottom with rounded/taped edges

I am wondering what you guys are doing for your screw pattern on boats with epoxy bottoms/rounded/taped edges. On the last boat we used the pattern from the Don Hill plans then proceeded to round the edges and tape. In looking at photos of other bottom intalls and it appears they used a lot less screw. I would like to put as few holes as possible in the plywood while still getting a good seal.

E. Landis

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Permalink Reply by Steve Sobba on October 11, 2009 at 10:52am

E. Landis , I used the sugestions from the Don Hill plans also, thinking at the time I would use UHMW plastic,... before I came upon this site. I used 1 to 1 1/4" #8 screws ss, pre drilled and counter sunk....started 2 " in from the side panels 3" apart on ribs 1 and 9... 3 to 5" on all other ribs and avoid the water notch locations per the Don Hill pictures and side instructions. If my countersink was to deep or had a good bite on the screw set I went back and made wood putty with System 3 T-88 adhesive filled and sanded before applying glass etc. I did not put glass on the chine. Again my boat has only seen water on the inside of it (rain) not been in water yet, (wating on the trailer to be finished),but that is the way I have done mine . Steve

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Permalink Reply by E. Landis on October 12, 2009 at 8:32am

Steve,

That is exaclty what we did on boat #1. Turned out great. No leaks at all. It just seemed like a ton of screws.

E. Landis

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Permalink Reply by Mike Baker on October 14, 2009 at 5:41pm

I have never done the rounded chine routine. I used to do screws every two inches now I do them every three. For comparison I am doing a UHMW shoe install on an older Tatman boat, it has screws every four inches on the bottom and every eight inches on the chine cap. I can see that the chine does not look like it sealed very well in a few spots and the owner says it does leak a little bit. I don't know if this was the recomended screw placement or just what the owner did.
Mike

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Permalink Reply by Randy Dersham on October 14, 2009 at 6:08pm

We grab a short stick that is about three inches to three and a half inches long and start marking. I like to have the distance be the same between screws for a clean an purposeful look.

If screws are counter sunk, two inches apart, and in a straight line then they create a weak line similar to the perforations on a bank check. More screws don't always mean stronger. Four inches will sometimes leave a bit of gap if you are turning a tight corner on a chine. So, three to three and a half has become our standard at the shop.

When we round the chine edge of the bottom and apply fiberglass tape under the final chine batten we will pre-drill a pilot hole and use a #14 Silicon Bronze ring nail. The pilot hole insures that the fiberglass has great adhesion to the side panel. Using a ring nail prevents the screw motion from the screw lifting the fiberglass away from the side panel. If you use screws to attach the chine batten and you have rounded and taped the chine joint then you should keep the tape going up the side panel at just below the mid height of the chine batten and place the screw just above the joint tape.