Back a few posts I mentioned that I would ponder moving the cockpit forward so it wouldn't be inline with the propellers, the Short Seaford drawing shows me what I really should do. That's move the whole forward fuselage a scale 3'-6" (or there abouts). There's a very important station which seems to be a production join line and it lines up with the front spar assembly where it goes through the fuselage. This station is also the one where the beaching gear is attached to as well. What the Seaford drawing shows is there's a space between the the windows now which were equally spaced either side of this station on the Sunderland (between the third and forth window starting from the rear most window). So what I'm going to do is add a plug into this spot and do the same as what Short did.
The Seaford had an increased planing bottom too, 6'-0" longer apparently. It had 3"-0 added in front of the step and 3'-0" behind it. The front extention would have been included with the forward fuselage stretch, but the rear extention is not so clear cut. It looks like just the planing surface was moved back along the rear fuselage which is a bit more complicated to do.
I've just bought a book on the Martin Mars, it's a Coulson/Ginter collaboration, and in the text the company that originally got hold of the Mars flying boats had evaluated a number of different flying boats to use as fire bombers. The Sunderland was one of them and what is really interesting to me, is what I calculated the Sunderland could carry as a water load, was pretty much what it was worked out to by this company, 2800 gals of water. Of course, this being a half Seaford conversion now, with much more powerful engines (in real life and my alternative) I think we could stretch that to 4000 gal I think