Choosing Your Side-Power Thruster

Every boat operator can benefit from having a thruster installed on their boat.

In principle, any thruster will do a job in any boat. However, the key to getting the full benefits of the thruster is to select the correct one to ensure that it will do the job you want it to. This is one of two main factors to consider when deciding on a thruster size for your boat.

Today most pleasure craft over 45' have a bow thruster as standard equipment. The thruster will usually meet the expectations of most customers when using the boat under normal weather conditions. The sizes used by boat builders will vary depending on the boat's intended usage and price level. In today's production boats of around 45'-50', the typical thruster will push the boat's bow against a direct side wind of 20-22 knots.

Some custom built or very high end boats may have a high power bow thruster that pushes the bow against a direct side wind of 24-26 knots. For boat owners who use their boats in more demanding conditions or have a strong current in their local marina, or requiring high performance, boat builders can offer upgrades to a more powerful thruster system. However, few pleasure craft need a thruster that can push the bow against a direct side wind of more than 25-27 knots.

The thruster's performance on a boat is basically determined by the boat's wind area, the wind area distribution and the thruster's tunnel position in the hull. By knowing these factors we can calculate the wind pressure on the boat and the center point of this wind pressure. From these calculations we can determine what thrust is needed to counter the wind pressure with the given thruster position. The boat weight is normally not a major factor for most pleasure craft unless they are regularly used in areas where the thruster is required counter strong currents.

Conclusion
The two main factors that decide correct thruster sizing are:

• boat owner performance requirements
• boat size, type and shape

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

The chart below give general guidelines to help in selecting a thruster for your boat. We do offer a more involved thruster calculation process for determining the correct model for your boat. If you would like to contact us to request further details, please feel free to do so.

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