Ooo, graph paper! Getting fancy now. When I sketch it out proportionally, the shanty boat is less long and skinny than I had drawn it. In fact, it looks like a tiny shanty. On a boat.
I'd kind of like to make the cabin a little more squat, which I can afford to do since I've dropped the cabin floor a foot or more below the level of the decks. However, I am limited by a funny thing: The head height of the porches. They need to be at least 6 foot at the lowest part (and even that's pushing it a bit and likely to bonk any of my NBA friends).
There was some concern about balance with the cabin shifted back from center a bit. Mostly that is to give us a big fine front porch and it only shifts the cabin back about two feet. Plus I heard a boatbuilder suggestion to shift weight toward the back. It lifts the bow and allows you to take oncoming chop a bit better.
Oh shit, and why do I keep forgetting the head? There is a little 1-1/2 deep x 3 foot wide bump out along the front (or maybe the back) where the head goes. Looking at it here, probably the back would be a bit more aesthetically pleasing. It bumps into the interior a foot and half also to make a tiny 3 x 3 foot bathroom.
The interior is 10' x 8'.
A little SketchUp magic and Voila!