Bow and Stern Jet Thruster

A trimaran can be challenging to manoeuvre. She is light and has considerable windage. Combined with my berth at home—where I have limited space and two right-angle turns to negotiate in and out— that was reason enough to invest in a manoeuvring aid. Initially I considered a retractable bow thruster. The forefoot has very little draft, which would force a conventional tunnel thruster further aft. The further aft the thruster, the less effective it becomes—hence the idea of a retractable unit positioned further forward.

I reviewed several systems, but the more I looked into it, the less I liked the thruster idea. Not only because of extra weight in the wrong place, but also because of vulnerability. I could easily imagine an anchor chain ripping off a protruding thruster unit.

So I chose a different approach: steering by water. I purchased the Jet Thruster system. A central pump delivers water under high pressure to the nozzles. A restriction in the nozzle creates a powerful jet. A remotely controlled directional three-way valve diverts thrust to port or starboard. As a bonus, thrust can also be distributed between bow and stern.

The installation involved a fair amount of trial and error. At first everything seemed fine, but after launching it turned out that the suction supply to the Jet Thruster pump was leaking. Hauling out again was not an option at that moment, so the repair had to wait until the planned final paint job. In the meantime, the connection was temporarily sealed with rescue tape—which worked surprisingly well.

During the paint job, the leaking connections were replaced and reassembled with new parts. This time the system was watertight.

Once all electrical work was completed, the real test followed: does it work or not? It did not—at least one of the two directions at the bow refused to operate.

Open the photo gallery to follow cause and effect. It turned out to be a simple mistake on my part, which was a huge relief once it had been found.

In the end, the system works brilliantly—which was the whole point.