After some figuring, the blade would be about 10 meters long measured past the mounting platform. The blade itself would be be built low into the mounting platform/gun base and would be stationary. This would extend the blade almost to the end of the Goldfish balloon, and would extend quite far from the sides of a Galleon. It would have a quad harpoon launcher mounted on the top in the usual gun position. The harpoons would have high vertical arcs, but very limited horizontal, much like the Lumberjack.
The weapon would have two functions. Function A would be primary fire using the left mouse button, which would fire the harpoons. They would automatically retract on contact. like the old harpoon. Harpoons would be fired sequentially, so you could get all four harpoons in one ship, or harpoon several ships. Reload would be long.
Function B would be secondary fire using the left mouse button, which would activate the saw. The saw would have no reload, running continuously for as long as you hold the button.