--Originally Posted 8/25/13--

We now consider the feasibility and benefit(s) reasonably to be expected of replacing this kit's entire tail - from the aft end of the missile compartment, clear back to the prop - with the after half of the Revell SkipJack:


How's that look - any better than the original Polaris Cutaway model?

If (as surely) you thought so, the explanation is nowhere better demonstrated than in the following comparisons:


Click on Image to EnlargeDocumented (top) only after the work described below, the kit tail was laid out, aligned with- and alongside that substituted from the SkipJack. Note the aft taper of these two molds simply does not match - to a very noticeable degree. Without question, the far more accurate - for either a George Washington, or the SkipJack on which it was based - is the fatter, more cigar-shaped tail of the (originally Aurora) SkipJack mold.

Just as in the forward hull-correction earlier, there is clearly an optimal point from which the tail of the Polaris Cutaway mold should be replaced: on the starboard side, immediately following the third-from-last vertical "cutaway window" frame - corresponding, on the port (and on the original, clamshell-hulled starboard) side, to a location 0.21" forward of the vertical (girdling) weld line immediately following the aft-most missile hatch.

On the SkipJack mold the corresponding cut would, of course, be most rightly determined by laying the build out against an accurate, (1/230-) scale drawing (which, remember, will differ in length for an Ethan Allen-, Lafayette- or Ben Franklin-class variant). However, for this quick tryout I again simply aligned the ends - actually, the aft stabilizers - of both molds (bottom), to certainly get within the ballpark (which again is going to be very close to perfect): as it turned out, on the SkipJack mold, exactly at the second-aft vertical (girdling) weld-line, following the sail.

OK, so the SkipJack butt is certainly what we want - but how well/easily does it install:


Click on Image to EnlargeThe first - and completely unexpected - thing that immediately jumped out, particularly when sighting down the hull (left), is the Polaris Cutaway hull is already narrowing - even before clearing the missile compartment - to substantially less beam than the SkipJack's - and thus narrower by the same amount from the start of the compartment, where the two matched perfectly. At the same time - with the keels butted flush - the Polaris hull remains still too tall for the SkipJack hull (center and right), as it would appear the vertical exaggeration has, if anything, increased. Remarkably, this pinching of the missile compartment aft remains visually undetectable, even when viewed from astern, as at right.

Of course, substituting from a narrower part of the SkipJack's hull, further aft, could alleviate the horizontal mismatch - but this would only exacerbate the vertical mismatch, and moreover would lead to an inaccurate LOA - also very probably with noticeably-undersized tail, which would begin to really defeat the entire purpose of the substitution, in the first place. On the other hand, the ideal solution (already proposed by my friend Rich), would at this point be to cut out from under the turtleback the entire missile section, and replace it with straight tubing - if you can come up with (including scratchbuilding) one - exactly matching the SkipJack's (maximum) beam. Cutting out the missile section would be easy to do. Obtaining the replacement tube - not so much.

Therefore I took a look at yet a third possibility - a compromise, as usual, but a good one, in several respects:


Click on Image to EnlargeExpand the incorrect Polaris hull's beam (left) - beginning by scribing/cutting most of it loose from the turtleback, under the aftmost 6 (of 8) missile hatches, on each side. A solid wedge (white plastic) can then expand the hull (bottom, at left) - then to be plated-in with an expanded keel (not shown) - such that the beam now matches the SkipJack insert (right). Note the vertical mismatch still remains - now, if anything, increased - however, with the hull now mostly free from the turtle-back, should now be easily correctable.

In fact, if the keel and just lower half of the hull are secured first, then - after these are fully-cured - the entire turtle-back could be completely removed, to facilitate mating of the upper hull "flaps" and any (minor) plating-in required to fill gaps - both here and also forward, where likewise required - as well as cleanup/reconstruction of the limber-line, and correction of the forward end of the turtleback, under the sail.

The resultant, overall hull form will be a quantum improvement:


Undoubtedly far closer to a real Polaris - or, again, to an Ethan Allen, Lafayette and/or Franklin - than the original, Polaris Cutaway mold.

Bet you never thought you'd appreciate how much better a Fatter Butt could look, huh?

Cheers,

-Matty