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How straight should the keelson be? '63 Seamate

Posted: Wed Oct 04, 2006 9:27 pm
by stampbj
I've got my new keelson wood squared up and I am ready to cut the bottom profile.

I'm wondering if the finished profile should be a gentle curve from stem to transom, or if the rear 5 feet should be arrow straight?

Since my old keelson was too rotten to save, here is how I drew the line.
I layed some 2x4's across the floor stringers, positioned the new keelson wood about 9" above the hull and clamped it all in place.
Using a level I transfered marks to indicate the ends of the new piece, then using a shop made jig I began to transfer a series of dashed pencil lines to the keelson, following the profile of the hull but stopping for each rib.
The hull is intact but is missing some wood in the center due to rot. My jig spans an area wide enough to bridge the rotten wood and is adjustable for the "V" angle. Still, my profile marks do not form a smooth line and I must average out the marks and redraw using a flexable strip of wood as a guide. (batten?)
My keelson will be just under 10 feet in length and as drawn, the rear 4-5 feet will be straight, with about an inch of taper from the bottom up to the rear. The next 4 feet will make a very slight curve, at the bottom and the front 1 foot will curve up 1/2 inch, a bit sharper, to the stem.

Before I make a $$ mistake, I would just like to ask...
As far as handling and performance, does the straight part sound allright?

Thanks, Brad

(edited for spelling, it was a laite night)

Posted: Thu Oct 05, 2006 6:48 pm
by john
How straight are your stringers? Straight stringers are also important.

I believe my keelson and stringers are straight for at least 4 feet. I'll try to measure this weekend. My boat is a 1960 Cruisers Inc 202 16'.

Posted: Thu Oct 05, 2006 7:56 pm
by stampbj
I checked the tops of the stringers with a 4 foot rule and they are as straight as can be. I will be checking the bottom edge tomorrow.

Thanks,
Brad

Posted: Fri Oct 06, 2006 9:41 pm
by stampbj
O.K., I laid the 4' straight edge across the tops of the ribs, along side the stringers and it is nearly straight for 6-7 feet forward of the transom.
At most I see a 3/32 bow in 4 feet. (convex hull)
And this could be due to an attempt I made 16 years ago to remove some hook caused by the trailer bunks.

At that time I sistered both sides of the stringers with 4 white oak 1x3's, six feet long, preloaded to push down at the center and through bolted to the stringers. It didn't appear to do much right away, but given time I would say it helped more than it hurt.

I welcome other opinions...