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Project Log:  Thursday, July 14, 2011

The insulation and sheathing against the hull beneath the dinette wasn't going to get done unless I did it, so I gritted my teeth and spent an afternoon completing the task.

In this instance, the insulation and sheathing was designed mostly to protect the contents (whatever they ended up being) of these lockers from any hull moisture that might be present during normal use.  I didn't plan to truly insulate the boat the way one might if one expected to live aboard in sub-zero temperatures, so all insulation I'd install along the way would be mostly along these lines:  to keep hull lockers sufficiently isolated from the effects of the sun's heat (from the dark hull) and condensation. 

As such, I saw no need for fancy, budget-breaking materials, though I'd researched the issue and at one time had thought of purchasing something like Armaflex, which comes highly recommended and would probably be an optimal choice if I had a steel boat or if I really needed insulation performance.  The price of this product was high, and I just didn't see the cost benefit here.  And anyway, I didn't have it now, and now was when I was doing the job.

Since we planned to use the boat seasonally in temperate latitudes, high-performance insulation against neither heat nor cold was required:  just a little buffer zone.  I'd good luck with basic 1/2" foam board in my other boat, where I'd used insulation at all, and I planned to go this route for most of the upper lockers, which I'd be building slightly down the line. 

For the dinette, it was a matter of using materials on hand so I could accomplish the goals and complete the dinette base structure. To that end, I chose basic blue Styrofoam board, a supply of which I had on hand from some long-ago forgotten project.  While this closed-cell product offered good performance, its main benefit was that it was already in the shop.  At least for these lockers, it was the right choice.

The insulation was 1-1/2" thick--thicker than I really wanted for space considerations, but ultimately I decided I could afford the minimal space reduction in this area since the curvature of the hull already limited the utility of these spaces to some extent.  I'd never really miss the volume lost to the insulation, and again:  it was on hand.  To keep this choice in perspective, one must remember that my shop is located far from any retailers, and I don't drop things to run out on errands without true need and planning.

On to the actual work.  The hull shape was such that I could get the insulation to bend more or less to conform to the curvature without difficulty.  I had to cut the large center piece of insulation into two pieces in order to get it into its compartment, as various cleats and obstructions prevented me from otherwise squeezing it into position.

To secure the insulation, and to provide means of attaching the plywood sheathing above it, I relied on a basic friction fit, and milled slim cleats for each side of each of the three compartments.  I installed the cleats, pressing them--and the insulation beneath--into the curvature of the hull and securing them to the bulkheads with small screws and some hot-melt glue.

The two-piece foam section in the center compartment, as seen the right-hand photo, stuck up proud of the hull in the center until I installed the plywood panel above it later in the afternoon, and this is responsible for the appearance of the gap between the sections.


Afterwards, I cut cover panels from leftover 1/4" cherry plywood.  Because the top edges of these compartments would be invisible and inaccessible once the top platform was installed, I didn't worry if the plywood completely covered the foam at that edge (as on the forward panel), but the center panel ended up shorter than I would have liked, particularly at the after end (the forward end extended to its natural end at the support cleat on the bulkhead), however, as this was the only suitable piece of plywood I had on hand that would cover the area.  Despite its appearance now, however, the panel would offer the needed protection to the foam beneath, and the shortfall would be out of sight and out of mind soon.

I screwed the plywood with screws to the wooden cleats that I'd used to secure the foam earlier.


Total Time Today:  4 hours

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