Figured this would generate more comment in the aviator forum than boat forum. Unusual River Boats Plying Vietnamese Waters | Flying Magazine
When I was going to summer camp in the Catskills back in the '60s, a fellow who lived at the other end of the lake had a boat made from a Super Constellation tip tank. I never saw the boat actually in use; it was always moored at the dock. Remember that Grumman made aluminum canoes and boats in upstate N.Y. for many years; I've used a Grumman canoe. I wonder if that is still a division of Northrop Grumman?
And let's not forget the famous belly tank racers -- another great use of belly/drop tanks http://www.pinterest.com/StigBlack/belly-tank-racers/
There's some pretty cool things built here from tanks and wings.. MotoArt Recycles Airplane Parts Into High-Flyin? Furniture | Inhabitat - Sustainable Design Innovation, Eco Architecture, Green Building
Here's the answer: they're not part of Northrop Grumman, but they're still being made with the Grumman name, in Marathon, NY. Here's the story: Marathon Boat Group.
Same with ours. Sitting out in the backyard right now, and still in great shape despite the fading yellow paint. It's a bit smaller though - approx ten feet or so.
Mine's in the crawlspace under my cabin in Wisconsin - about a 200 foot downhill jaunt to the lake. Light blue paint has lots of scratches and chips from easing it between logs & rocks into lonely little bays. It will probably last at least another couple lifetimes without need of repair.