THRUSTER SIZING

 

In principle, any thruster gives a certain effect on board, but for optimum maneuverability is important that the thruster is designed to provide sufficient thrust under all boating conditions.

Today, most boats come with thrusters fitted standard from the factory. Mostly the factory mounted thrusters meet basic requirements of some customers under normal conditions with minimal wind, but for some skippers, it may be wise to consider a more powerful thruster if you use the boat under more severe conditions than the average user. Most builders offer therefore thruster upgrade on customer request.

If you want to use the boat alone, a DC Speed Control system in combination with a bow and stern thruster, and the unique Hold function will provide a valuable assistance with the mooring.

Thruster power is determined mainly by boat porch and not by its weight, which is a general perception. When we know the boat’s total wind area, the boat’s pivot point and the location of the tunnel, we can calculate the wind force on the boat area and center point. Hence, we can calculate the amount of force needed to push the bow into the wind at a given wind speed.

Example

With a 45 foot boat, there are four thrusters to choose from within what we designate as standard thrusters. If your boat has a small porch and just being used under good conditions, with little wind, you can choose SE80. If you need more thrust, without having to increase the tunnel diameter, are SE100 that option. If the boat can accommodate larger tunnel diameter can be increased tunnel diameter of 215mm or 250mm to find those best suited for your boat.

Conclusion

The two main factors to dimension one thruster are:

  • Boaters requirements for thrust
  • Boat size and hull type

Important: By increasing tunnel diameter, the thruster is more efficient and generates less noise.

Side-Power dimensions table

Thruster ModelSE130/250TSE170/250TC
Thruster position A21.2 kn23.9 kn
Thruster position B22.4 kn25.2 kn

Side-Power dimensions example

The example above shows the different wind speeds that two different thruster installations can counter and the increased leverage gained when the thruster is positioned further forward.