Any one here ever see one of these. It is called Sea Archer.It is like an inline compound bow. There is a handle toward the front where the band attaches.There are 2 horizontal wheels one above and one below the barrel toward the rear of the gun.One end of the band goes to the opposite side of each wheel.This means one rotates clockwise the other below rotates opposite. There is a small tube on a cable that centers on the rear of the barrel. As the spear is fed down the barrel it comes out the rear and fits into this short piece of tube which is attached to heavy cord which attaches to the wheels. You hook one finger on each side of the spear holder and pull back. There is a true compound action at about 3/4 pull.It is about 50 lbs. draw with a breakover of 25 lbs. Havent had it wet yet but hope to soon.

Can you post a picture?