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Dan wanted a bow thruster to make close-quarter maneuvering easier on his inboard cruiser. But, like most of us, he didn't have the nerve to cut a large complicated hole below the waterline nor the professional fiberglassing expertise needed for the job. His other option? An electric stern thruster, which is easy to install on a flat transom, and well within the skills of any do-it-yourselfer. He bought one from Vetus (410/712-0740, www.vetus.nl). The thruster's joystick control, wiring, and prop/tunnel are all stock, but there are many choices for the electric motor. Vetus helped with this over the phone, as well as with installation questions as the unit's manual isn't all that good. The only major complication encountered was that the thruster requires a dedicated 12-volt battery be wired into the boat's DC charging system.
PARTS: Electric motor (ignition protected) Vetus BOW55121, $3,000 Prop/tunnel Vetus Stern 150P, $412 Joystick control Vetus Model BPJE, $273 Fuse holder Vetus ZEHC100, $45 250-amp fuse Vetus ZE250, $16 Wiring harness (33') Vetus BP2910, $66 12-volt battery 100-to-200-amp-hour
SUPPLIES: • 3⁄8" electric drill • 3⁄8", 1⁄2" drill bits • 3" hole saw • Jigsaw • (2) 5⁄8" wrenches • 3⁄8" stainless-steel hex bolts, washers • Outboard motor gear grease • Sikaflex 292 sealant (or equivalent) • Cable ties and clamps • AWG 000 cable • Solderless ring terminals • Heat-shrink tubing • Heat gun
INSTALLATION: Locate the athwartship center of the transom and draw a vertical line. Tape the thrust tunnel's paper mounting template to the transom. Be sure to line up the template's "waterline" to your boat's actual waterline, not the painted one. Check and double-check this. It is essential that the thruster's tunnel is parallel to the water's surface.
Before drilling any holes, check inside the boat to be sure that there are no obstructions and that there is a minimum of 1' of clearance to accommodate the internally mounted motor. Also be sure that no bilge water can reach the installed motor.
Drill six 3⁄8" holes for the thrust tunnel's mounting bolts. Next, drill a ½" pilot hole for the jigsaw's blade and cut a 6½" hole for the motor mount. De-bur fiberglass edges with fine grit sandpaper.
Mount the thruster tunnel to the transom using generous amounts of sealant on both sides of its gasket. Before securing the tunnel, coat the threads on its nuts and bolts with grease to prevent them from seizing in place. Push bolts out from inside the hull, keeping the nuts and lock washers on the outside. Check that the prop still clears the thrust tunnel by a minimum of 1⁄16".
