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Project Log:  Friday, February 11, 2011

Earlier in the week, I took a few moments to wash and sand all the new tabbing on the after fuel tank platform.  I'd give the new epoxy as much time as possible to fully cure before painting out the area (new epoxy tends to adversely affect the curing of some paints), after which it'd be ready to accept the tank.

My next big event was to prepare for and foam in the new engine room wing tanks.  Although I purchased additional, new 2-part expanding polyurethane foam for this task, I also had partial containers dating back to a job about a year ago that I hoped (and planned) to use.  Before proceeding, however, I thought it wise to perform a mixing test of the older product.

I mixed 2 oz. of each part (the smallest practical amount I could measure in the containers I had) and left the container to see if the foam still worked.

It did.

Unfortunately, I miscalculated how much of the product I'd need, and ran out of foam before I'd finished both sides.  However, I managed to fill the port side up about as far as the top of the after bulkhead, and part of the starboard side.  I'd have to buy more foam to continue.  Even though I'd taped off the openings around the drain valves, some of the foam still leaked out through some of the openings.


Fortunately, the lack of sufficient foam didn't put an end to the day's work.  Though I'd hoped to complete the job, I could easily finish some other time.  In the meantime, I spent quite a bit of time contemplating the bulkheads in the engine room and working out how to proceed from what I had--that undocumentable sort of rumination that's an important part of the design and construction process in any job.

Perhaps, dear reader, you may recall that I chose to build the new tankage support bulkheads somewhat lower in order to allow the tanks to be installed over their tops, which allowed me to reinforce the bulkheads inside and out and make for the soundest installation possible.  This meant that these semi-structural bulkheads were several  inches lower than the minimum level I required in order to build the pilothouse sole supports--my immediate construction goal and important foundation step in the reconstruction of the entire pilothouse interior.

It was time to face the consequences, for lack of a more appropriate turn of phrase.  This was one of those situations where describing the plans I eventually formulated was more difficult than actually building it, so bear with me through these wordy descriptions and wait and watch through the next several work sessions, as needed, for the setup to become clear.

Complicating the situation was the fact that the aft end of the pilothouse floor was necessarily by design below the level of the molded aft bulkhead, meaning that supporting the aft end of the pilothouse sole required more thought than simply securing a cleat to this bulkhead. 

In the original construction, there'd been a 1/2" thick sheet of plywood bolted through the aft bulkhead that hung down beneath the edge enough to allow the sole some means of support there--not an installation I planned to emulate, as it was awkward, bulky, reduced access to the spaces behind, and required through bolts from an exterior finished surface.

After scouring my photo archives, I couldn't find any old pictures that truly showed the original setup, so these four (all taken in July or August 2010) are the best I can do to attempt to illustrate the previous installation.


I wanted to build a removable, strong beam that would span the width of the pilothouse at the aft end, obviating the need for the awkward down-hanging plywood and also providing better access to the spaces behind as needed.  To support the beam at the ends, I'd need to use one of the longitudinal bulkheads, bringing me back full circle to the question of how best to arrange things.

I'd built the fuel tank bulkheads 48" long, plus an additional 1/2" at the after end where the transverse bulkhead closed off the space.  This was just slightly short of the distance to the molded fiberglass aft pilothouse bulkhead, but it had seemed wasteful to make the bulkheads an inch or two longer, thereby requiring using the length of a sheet of plywood rather than the width, so from early on I'd chosen this particular compromise as it had little overall bearing on strength or structural integrity--only on construction convenience.

Therefore my first problem, as it were, was to extend this length as needed to provide the support not only for the pilothouse sole beam, but also for the plywood panels that would form the visible cabinetry inside the pilothouse.

Plywood is, of course, 48" in width, and I planned to eventually use a full width of cherry plywood for the top portion of the side bulkheads, so the first thing for me to determine was where the 48" measurement would land on the forward bulkhead.  I clamped a 48" metal rule in place at the top of the bulkhead, and noted where it landed at the lower end.


This ended up roughly 3/4" above the top of the cabin sole support, which was fortuitous since the finished cabin sole would likely be roughly 1" thick (18mm substrate plus 1/4" finish material), meaning the plywood seam would be naturally hidden by the cabin sole once installed.  This left roughly 6" between the end of the cherry plywood and the top of the fuel tank bulkhead beneath, a gap I'd fill in with a section of structural plywood and which, when complete, would (finally) give me the sturdy structure required to support the cabin sole support cleats.

At the after end, I eventually decided that by installing an extension of the short transverse bulkhead (aft end of the fuel tank), I'd create a surface on which I could install a strong cleat, allowing the "fill-in" section of plywood to pass by and create the extra length and support needed for all the remaining structure. (Perhaps I should have simply built this bulkhead taller before, but I chose to keep it level with its longitudinal cousin since I just wasn't sure what I'd need from there.)

Fear not: all will become clear (assuming it seems muddy now) as construction progesses.

In any event, I templated and cut/fit 12mm Meranti plywood extensions, which I allowed to extend roughly 3" above the tank tops to provide a place for support cleats and tank hold-downs, which I'd install sometime later.  However, this height allowed access to the space behind (port side only), which I wanted to keep open for future access and unknown uses.

With both bulkheads--port and starboard--cut and fit, I glued them in place to the bulkhead beneath and against the hull with epoxy adhesive.  The camera angles in the photos below make the alignment seem off-kilter and wacky, but the bulkhead extensions were plumb and level as required (though the starboard water tank was pitched somewhat inboard--something I'd take care of before continuing).



Though I'd reinforce these new installations with fillets and tabbing later, for the moment I left them to cure overnight.

Total Time Today:  4.25 hours

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