Shearwater Hybrid rear bulkhead & coaming apron too low

I have all the forms tacked in place except the ones that hold the coaming apron on my SWH. Everything looks really good except the rear bulkhead is about a half inch lower than the form 11 that is six inches behind of it. The apron snaps in place on top of the coaming form that fits on top of forms 8, 9, 10 and 10 1/2. Form 10 1/2 sits against the rear bulkhead and is the same heigth.

My problem is that the rear strips are about 1/2" above the rear of the apron which is cut from 4mm okoume and sits on top of the rear bulkhead. How I do I mate the rear strips up with the coaming apron that is too low?

PS

 


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RE: Shearwater Hybrid rear bulkhead & coaming apron too low

   I failed to mention in my initial post that I am building a Shearwater Hybrid from plans and did not buy the kit with precut forms.

I cut everything according to the prints and it all fit well except it seems that rear bulkhead and form 10.5 are too low.

When I lay a cedar strip on top of the forms from the stern up to the coaming apron, the strip sits 7/16" above the apron. I cannot bend the strips down to meet the apron in such a short distance but I can bend the 4mm apron up to meet the strips. That leaves the problem of having a 7/16" gap above the rear bulkhead and the bottom of the deck. I am thinking the soultion would be to shim up the bulkhead and cut a taller form for the apron.

While tis should work, how is this possible that things are not lining up properly? Could the plans be wrong with no mention in the instructions?

PS

 

RE: Shearwater Hybrid rear bulkhead & coaming apron too low

Hi Peter, 

i have built a number of strip builts and first, you are doing all the right things by setting it up and testing with some strips before you start stapling/glueing a lot of things.

so the first thing i would say, based on your description, is that if this is about the deck it's fundamentally what is going to look right/best and you don't have to worry about any performance, structural or handling issues.  the second thing i would say, is it's not uncommon with a long boat, even one that comes from a kit, to have some misalignments develop that you have to address.  if you are building from plans, its even more challenging....everything in a kit is computer cut.

so your approach to shimming up the bulkhead and bending the apron up a bit is just fine if visually, you like the look. 

on how things can go wrong, a common problem in building from plans is not properly addressing the thickness of the material in any part and the consequence on various sections when they are skinned with a 1/4 inch skin and how that interacts with a real build.   plans generally do not have an adjustment for skinning/construction,  they are just the sections.

the second thing is key reference marks that can reliably be relied upon and confirmed.   in a traditional strip built (not hybrid), you have a strong back and a clear mark on ever section on how it lines up on the strong back and its easy to check with a laser or other effective level or reference line.   on a hybrid, you build ontop of a hull....which is not as easy to line up as a strongback.

the third thing is little differences can easily accumulate in a build and with the length can get multiplied in terms of how they may interact.

fourth, you might just have cut something wrong and not recognized it.

and fifth, maybe something actually is a way it is but you did not have that in your minds eye and therefore are judging it as wrong when it is what the designer intended.

anyway....all kinds of fun sources of error....i have seen a lot over the years.

h

RE: Shearwater Hybrid rear bulkhead & coaming apron too low

   Hi

I am about 10 days ahead of you building my Shearwater Hybrid 16, although I bought this as a pre-cut kit here in the UK.

Despite great care fitting the forms and laying the deck I had a gap of between 5-8mm approx (sorry I do metric!) between most of the rear bulkhead and the deck underside. There was a much smaller gap above the front bulkhead.

My mesage is not to worry. When you dry fit the deck to the hull take ages with straps and other measures and I also applied a fairly decent weight (a sack of about 8kg) over the bulkheads. I used weights and also blocks of wood under the straps at different points along the boat to distribute the load where i wanted it too. The overhang of the outermost cedar strips may mean that if you just use a tight strap nit can actually squeeze the deck and lift the centre more slightly otherwise.

Anyway practice several times with your system and make sure it all sits snugly. I got it realy tight then left it overnight and everything eased into place. When I finally did the bond the bulkeads fitted and stuck pretty much all the way along with a smear of really thick epoxy on the top edge. Easy to apply a small fillet later to tidy up.

Hope that helps. I have built the coaming now and therefore onto the last coats of epoxy before finishing. I can share pics if you like and be good to hear how you are doing

This is my first ever wooden boat build!

Bruce Woodhouse

N Yorkshire, England

RE: Shearwater Hybrid rear bulkhead & coaming apron too low

   Hi H & Bruce,

After posting, I talked to Jay from CLC. He told me that no changes had been made to the plans since it's inception in 2007 and the prints should be correct. He suggested that I try adjusting forms #12 and #13 to lower the strips on #11 and the apron.

I broke the hot glue joints loose and tried to reposition the forms but #11 was still holding the strips too high. I ended sanding a little off the tops of #11 and #12 which brought the strips down a little. There is still a small gap of about 4mm or 1/8" but that should be good for attaching the strips to the apron. If there is any gap between the bulkhead and deck after I glue the top on, I will just fill with a fillet.

I have moved on to stripping the deck and will be adding the king planks and cutting my accent strips out of basswood and cherry today.

PS

 

 

 

RE: Shearwater Hybrid rear bulkhead & coaming apron too low

áááIt is worth getting the strips really level where they attach to the apron with the upper surface flush. When you fair and sand the deck becreally careful here as it us very easy to go through the top of the plywood layer and this looks a bit unsightly at the rear if the apron where it is not covered by the coming.

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