Page 1 of 1

more about ballast.

PostPosted: Wed May 25, 2005 10:06 pm
by Gene Rosson
Ec12 newbie visits local regatta, spies boat for sale. Bought boat cheap (caveat emptor). It is a Hickman, apparently never commissioned. Ballast was already installed, deck installed. Boat weighed 22.7 pounds. Seemed a bit heavy to me. Built tank, tested boat. Great fun. Close to 43" WL. Deck dimensions within tolerance, plus side of standard in forward sections, minus aft, hard spots between 30 and 40 inch inch sections. Two degree positive trim. <i>Optimizing</i> suggests less trim. Keel width 2.06".

Ripped off deck, beams, king planks, inwales, and ghastly excess of adhesive. 23 ounces. Have built rigid sheer/deck template with which to fair the lines smoothly. Template has fudged the tolerances to be skinnier in front and fatter aft. All within rules of course. The premise is that the deck dimensions have some influence on the volume of the underbody.
Q1: Am I on the right track or am I just whistling dixie ? Maybe shooting myself in the foot ?
Q2: Does the sheer line, in the elevation view, have a curve on conventional EC12s ? This one has 5/8 inch of pleasing swoop. It might make trouble if a straight king plank is attempted.

PostPosted: Thu May 26, 2005 4:19 pm
by greerdr
Whistle "Dixie" any time around me.I used the deck substructure to bring the few hulls I've built into compliance with the rules.I too went a little beamy aft. The sheerline seems built in to the hull .
Really 1 1/2 POUNDS of adhesive?

R.C.Greer

PostPosted: Thu May 26, 2005 8:19 pm
by PaulP
Gene,
The guys in Seattle did some testing on the EC12 hull and found the hull shape and displacement at the given waterlines is not affected by the narrowing or widening the beam (within tolerances).

Widening the beam does increase the volume of the hull, but all the "give" is in the area above the waterline so it ends up making no difference in the amount displaced by the boat.

You'll find your boat will be a better unit by removing the heavy deck and glue in that you will have to add more ballast to get it back within spec. That ballast will be lower and will make the boat stiffer.

Hope this helps

Paul P

PostPosted: Thu May 26, 2005 9:09 pm
by PaulP
Gene,
Second post regarding the sheer curve and kingplank.

The hull sheer does "droop" about 5/8". The deepest spot is about 40" from the bow. The king plank runs straight from the bow to the stern. If you make it follow the sheer, the boat will come out looking "swayback". (Embarrased, voice of experience)

Build it with the straight kingplank, you'll be a lot happier

Paul P

PostPosted: Fri May 27, 2005 1:21 pm
by Gene Rosson
Paul and R.C.: thanks for the feedback. Your comments duly noted. No not 1.5 pounds of adhesive but a lot of excess. I was referrring to the whole deck assembly. I'll post some more dumb questions soon. Thanks again.

Gene

PostPosted: Sat May 28, 2005 6:28 am
by Jim Linville
Gene: My Daddy always told me that the only dumb question was the question that wasn't asked. I agree. I still post "dumb" questions here, but I've found that many/most of them have already been asked (and answered). Try running a couple of key words through the "Search" function of the forum before posting.

Almost all of my questions are now answered by my good buddy, Serch.

--Jim L