Boatbuilding Blog

January 16, 2007

Questions for Sam (and Answers)

Filed under: Building - Before Flipping — tomlarkin @ 7:01 am

I wrote Sam Devlin with some questions about how the hull is assembled. He replied right away, with nice clear answers.

 

Your book says to assemble the hull right-side up by stitching the panels together, install the bulkheads, and then flip it over to finish the hull exterior. However, the Godzilla is assembled upside down because of the forms needed for the round stern. The panels are laid over the bulkheads at the stations and stitched together. The stern is laminated on. Then the outside of the hull is finished normally and the hull is flipped right-side up to install the interior.

Questions:

  1. Q) Do you attach any or all of the bulkheads before flipping the hull?    A)We set up the bulkheads on the shop floor or on a simple strongback jig and then drape the panels over the bulkheads.. see pics.I recommend using the real stuff for the bulkheads and do at least tab everything together before rolling rightside up.. Building upside down helps to eliminate one of the rollovers and saves a bit of time… We glass the verticals from under the hull and tab the overheads (the overheads can be final glassed after the hull is rightside up, avoids epoxy in hair…
  2. Q)In the drawings all the bulkheads run to the gunnels in height. However, on my model, all of the bulkheads (except number 5) are cut down to deck height, about 18″ lower than the gunnels. (I’m not making a raised foredeck.) That’s a lot of extra work and wasted marine ply. Do you see a problem with me making my bulkheads shorter and letting the side panels run wild the last 18 inches? See drawing:
  3. A)I would proceed as you are thinking but put some stand legs along the edges of the bulkheads to give support at the sheer….. You will need to add some structure for that support anyway….

  4. Q) I’m planning on pre-coating the insides of my hull panels with epoxy (3 coats, wet on wet). This would happen before assembly, while they are laying flat. Before stitching together I would wash any amine blush off and sand the surface with a dual-action sander. I think this will save me a fair amount of time and labor later. On the outsides of the panels I plan only on sanding and filling the scarph joints before assembly. Do you have any reservations about this approach?   A) I am okay with that approach, it adds some stiffness to the hull panels but that doesn’t hurt anything in this design…

He enclosed some images of the bulkheads on the strongback. They are for a different boat, but the idea is the same.

Advertisements

Leave a Comment »

No comments yet.

RSS feed for comments on this post. TrackBack URI

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: