The "weeder" refers to the small gas engines which were originally stolen from Weedeater string trimmers. Apparently, a few years back some brilliant guy thought "Hmmm, I've got this nice model boat hull, but I don't have an appropriate nitro engine, but I've got this weedeater thing which has a cool engine, and doing yard work sucks, so I can kill two birds with one stone by discombobulating the engine out of the weedeater and installing the engine in the boat." And thus, Weeder boats were born.
I currently own 3 weeder boats:
48" Aeromarine 'Challenger' with a Blois modified Zenoah G-23 and Marine Specialties double rudder offset surface drive.
43" AC Model Boats 'Wild Thing' with a Marine Specialties Stage 1 modified Zenoah G-23 and a Hanson tuned pipe.
43" AC Model Boats 'Magnum 67' with a Marine Specialties Stage 1 modified Zenoah G-23 (And the humongous Marine Specialties steel tuned pipe).
Unfortunately, the weight of the Marine Specialties tuned pipe was too much for the very low transom on the Magnum 67 so I moved the pipe to the Wild Thing.
Check out the rather abrupt left turn made by the boat in the background.... That's some radical steering!
Here's the Magnum 67 with the "normal" Hanson tuned pipe. The Magnum behaves much better with the Hanson pipe.
Here's Bob's boat. It's also an AC Models Boats Magnum 67. The bondo on the bow shows what can happen if you take your eye off for even a couple of seconds.