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Stitching things together on a table the manual says to make sure the bottom is flat whether on a table or on sawhorses. But when I tighten the stitches to bring the seams together some rocker sets in near the ends. The bottom sits flat on the table until about 3 feet from the stern then it turns up and at the curve where the stern ends of the bilge panels turn up the bottom is up off the table about 5/8 inch. The bow does the same thing but the point where the forward ends of the bilge panels turn up is only about 1/4 inch above the table. My table is of course not perfectly flat but it's close. So my inclination is to continue, assuming that this is how it should be as the edges of the panels are together and loosening wires to let the bottom sit flat on the table would result in substantial gaps in the seams. I cannot find any specification in the manual or the drawings indicating how much rocker there should be - can anyone point me to to the answer (if there is one - I might be making much ado about nothing but don't want to start gluing until I'm sure things are where they should be).
Thanks,
John in sunny San Diego (88 degrees yesterday - January 15 2021)
4 replies:
RE: Mill Creek 16.5 rocker?
OK thanks - I've put a couple of pieces of 2x4 on edge across my table to simulate sawhorses. Setting the boat on these it takes on a bit of rocker as the seams come together so I feel confident to proceed to the next step of filleting and taping. Interesting phenomena I noticed was that placing the 2x4s in different places along the hull resulted in my "beam spreader" stick getting tighter or looser depending on where I put the 2x4s. Too close to the ends the stick falls out, moving in from the ends a few feet it is held firmly in place.
RE: Mill Creek 16.5 rocker?
sounds like you have it worked out.
on those 2X4s, make sure, if you haven't already, to have something that gives some support to the chine (where the bottom panels meet the side panels) to prevent pressure on the centerline. (which can create a hollow/flat spot)
before glueing, you just want to ensure that the hull is symetrical and fare and no twist. but it sounds like you have it under control.
h
RE: Mill Creek 16.5 rocker?
» Submitted by hspira - Sat, 1/16/21 » 2:48 PM
Hi John in sunny San Diego,
yes, it has rocker. here is a side drawing with a straight reference line.
typically when they say flat they mean no twist or any other things going on that is going to distort the hull. but it does not mean to push the boat into the flat surface. the boat should pretty much assume its proper shape when stitched together. my preference is to build in slings/sawhorses so the weight of the hull does not distort the shape and allows it to assume its proper shape with the least difficulty.
relative to a lot of kayaks, a hull as described below would be described as relatively little rocker.