The bow thruster is almost unanimously accepted by boaters. Even if it is offered as an option by boat sellers, it is often adapted as soon as the boat exceeds 7 m. It must be said that its use facilitates port manoeuvres so much that once adopted, it is difficult to do without it.
The principle of the bow thruster is simple: a propeller installed at the front of the boat across the step propels the bow to the right or left.
The most common thrusters are installed in a tunnel. A kind of hole that passes through the hull in which the propeller is installed. Stars often choose this installation, as it is not annoying when sailing with the bow lifted above the water level. For a sailboat, the hole of the tunnel at the front, creates disturbances for the good walk under sails. Hence the solution of installing a retractable thruster that is stowed during navigation and deployed for manoeuvring.
With an electric motor at the front of the boat, a thruster has two main faults: it makes a lot of noise and cannot run for long.
The noise and operating time of the thruster
Anyone who has followed a harbour manoeuvre will know what we are talking about: a thruster is noisy. It both bothers passengers on board (especially those in the forward cabin) and people in the vicinity. It's hard to hide when you use the thruster
With its powerful electric motor which is not well cooled (in a trunk under a berth), a bow thruster should not be used more than a few minutes (2 or 3 depending on the manufacturer). If you try to use it longer, it heats up and stops. To avoid in the middle of a delicate docking manoeuvre!
The RimDrive solution from Vetus
The equipment manufacturer Vetus has launched a bow thruster based on a new technology that offers an answer to the two previous problems. The RimDrive is based on a 48 V DC motor whose stator winding is located all around the tunnel. Only the propeller (equipped with magnet at the end of each blade forming the rotor) rotates without central axis.
This engine has practically no friction and therefore makes little (or no) noise. The absence of a central shaft does not require sealing and eliminates the risk of leakage. In addition, the motor is permanently soaked in the cooling water.
Thus the RimDrive makes no noise and can be used in continuous use (until the battery runs out!). This product is available with 125 and 160 kgf power ratings.
