More on the Bow Thruster

Getting the bow tube mated to the hull worked out well. Today it was time to attach the machinery to it. This sucker is heavy, at about 85 lbs, it's a blend of precision engineering and brute force, will completely drain six average car batteries in 3 minutes flat. It's my pride and joy and I can't wait to throw the switch.

The idea is, to place the prop (nice red job) precisely on the center line of the boat, and centered in the tube. The spec in the manual says, minimum of 1.5mm clearance between the walls of pipe and the prop. Given that this spins at 4250 rpm, it's really just a big food processor and will eat up the walls of the tube in no time if not aligned perfectly. So it's back to making holes, 4 of them, 3 x 9mm & 1 x 30mm, in just the right spot. Again it's measure, measure, measure and viola, I got it right.

Tube then needed to be aligned precisely in the hull because the motor housing and motor itself reside inside the boat where it is dry. It also needs to fit within a specific space which requires a tilt to it's angle. So it was more fitting and unfitting, marking , checking before I was confident enough to mark for the final cuts.

I've also cut out 1-1/2" wide flat trim pieces that will be welded to the exterior of the opening to act as double plates making the hull twice as thick around the tube weld. This will allow a smooth fairing job and a nice radius on the transition.

Must think up something to do with these cut offs, they look kinda modern artish don't you think? At one point while I was fussing with the fit, I had the prop set on it's shaft without the key so as to be able to turn it by hand. A gust of wind blew through the tunnel resulting in a nice pinwheel effect convincing me of how well this was going to work. If you're on dialup you may not want to play the video. Welding is finally all done, took four spools of mig wire to finish it but it's strong as hell. I'll be adding a ton of epoxy fairing compound around the aperture to finish it up and smooth out the transition. Very happy with the result, this is going to be bulletproof. Here's an interesting addition, anyone seen one before? I hadn't. This hook I added to the bow is about a foot below the water line. It's about 8" long, sticks out about 5" and is sharpened to a knife edge on the top curve. I learned of the device from an Alaskan fisherman I met down here. He has one on his boat and swears by it. Seems there are all kinds of nets, fishline, ropes and crap of all sorts floating out there in the ocean, this will cut whatever gets trapped in it before it gets wrapped around the prop. I like it! I like it a lot!!