Armed with new information and answers to my questions from yesterday, I continued work on the cabin mockup today.  I began with the starboard side cockpit coaming.  It was abundantly clear to me that this coaming needed to taper downwards as it ran aft, rather than remain a constant height, so after looking it over and doing a few test measurements, I decided that the aft end should be 2" tall, with the forward end remaining at 3-1/2".  With these two measurements marked on the cardboard, I clamped a stiff batten in place between the lines and made a mark, then cut off the excess.  I formed an elliptical curve at the tail end of the coaming where it overlapped the aft deck, again using one of the port frames as a template.

To simulate the eventual thickness of the coachroof structure, I made marks 1/2" up on each side of the plywood so that the mockup would roughly simulate the final height of the cabin.  A bit of discussion seems in order here.  The concept drawings didn't take into account the thickness of any coachroof structure, which meant that the visual height would have to either be a bit higher to accommodate it, or the thickness of the top would protrude a corresponding amount into the cabin below.  With potential headroom a precious commodity, and with an already-defined need to slightly increase the height of the cabin trunk sides to better accommodate the port frames we had on hand, I decided that only the framing for the coachroof would be below the tops of the cabin trunk, and the actual top--probably two laminated layers of 1/4" plywood--would protrude above, the edges to be covered with trim. 

Removing the plywood strip to the bench, I laid out the curve for the coachroof crown.  Rather than simply strike an arc between the three known points, I used a layout process that provides a dynamic curve that creates a more pleasing overall shape.  I first researched this process a few years ago for another project and won't repeat the details here, but more detail is available at the following link.

Sidebar: Details on the Beam Crown Layout (Opens in new window)

Once I laid out both sides, I cut the curve with a jigsaw, and faired it by hand.

To further enhance the mockup, I glued the port frames in place on the cabin trunk.  Rather than locate them symmetrically from each end, as shown in the concept drawing, I chose to bring the forward port aft by a few inches, which improved its clearance between the top and bottom of the cabin trunk, and also looked just a bit better to my eye.  The after port's vertical center is 13" forward of the aft end of the cabin trunk; the forward port's vertical center is 16" aft of the forward end of the cabin trunk. 

Please pardon the poor quality of some of the final mockup photos.  My new camera took a little bounce with the lens extended (i.e. camera turned on), and this seemed to damage irreparably the operation of the lens--and therefore the camera.  So I had to switch to an very old camera that I keep as an emergency spare--though this old HP is still the best camera, in terms of longevity and ability to take whatever's been thrown at it, that I've had to date.  Miniaturization and consistently downward prices are nice and all, but sometimes large and heavy has some advantages.

Yet another new camera is on the way for tomorrow, after which I'll send off the old for hopeful warranty repair.  (It's only one month old.)  With luck, timing and weather tomorrow will allow me to pull the boat outdoors for some pictures once the new camera arrives.

1.  This represents a reasonably accurate first approach to replicate the conceptual drawing.   There may be adjustments needed here or there.

2.  In the end, it's only cardboard and plastic.  While it does a fair job in helping to envision the final product, it's far from perfect, and these flimsy materials don't necessarily bend and curve the way wood will when it is used to actually build the structure.

3.  I am not yet sure about the port placement.  In the photos of the mockup, the ports are equidistant from the top edge of the cabin trunk, a distance set by the forward port based on the possible clearances.  This ends up being 1/4" down from the top in this case.  This is a first guess, and I'm struggling with whether the ports should be aligned according to the deck line, or equidistant from the top edge of the cabin trunk, or some other alignment. 

I did not find any true guidance from my sources, and have had a little difficulty truly determining how ports should be aligned when the cabin trunk is shaped like this.  A more distant view of the boat will be telling, and I plan to pull the boat outdoors so that we can get a better view.

Before gluing the ports in the position you see here, I went back and forth about it, and held the after port in place the same distance off the deck as the forward one to see if that was the right position; that didn't seem to look right somehow, at least not from up close. 

One thought I have had since installing the ports is that perhaps they ought to be aligned along a horizontal centerline from the forward to the aft side of the trunk--that is, mark 3" up from the deck at the forward end (half of the total 6" height) and 4" up at the aft end (half of the 8" height there), connect the two points with a line, and align the horizontal centers of the ports along this line.  This would bring the after port down somewhat, while the forward port would stay where it is.

Note that the tape measure housing requires that you add 3" to the measurements shown.  In this series of photos, each set of three photos goes together in an attempt to show where and how I located the tape for each measurement.

The mast, when installed, will of course impact the cabin design in inalterable ways

Total Time on This Job Today: 7.5 hours

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