1. WHAT DOES A THRUSTER DO?
Bow and stern thrusters make docking much easier by giving you control over the bow, or bow and stern, of your boat. The thruster has a propeller located inside a submerged tunnel and uses this to push the boat at that point, moving it towards or away from the dock. Using a joystick or push-button control panel, you can move the bow or stern sideways to counteract crosswinds and currents, making it much easier to manoeuvre in confined spaces.
So, how can a Vetus bow thruster make your life easier?
- It helps you stay in control during docking and manoeuvring, even when entering a very tight berth in a busy marina
- It enables a single crew member to pick up and secure dock lines while you gently shift the boat sideways between pilings or mooring points—smoothly, quietly, and without excessive effort or shouting
- It makes it possible for you and a small crew to confidently manage a larger, more comfortable vessel
- It reduces the chances of colliding with other boats, docks or pilings, helping you avoid damage
- It lets you handle your boat with skill, elegance and confidence!
2. TYPES OF VETUS BOW THRUSTER
Standard DC thrusters
Standard DC thrusters are the traditional and most widely used type of bow thruster. They use a brushed electric DC motor (12v, 24v or 48v) to drive the propeller.Controlled with simple and intuitive on/off port-to-starboard joystick or switches, they are easy to operate and available in a wide range of sizes with thrust outputs from 25kgf to 285 kgf.
These thrusters are ideal for boats from around 6 to 30 metres and offer a cost-effective and reliable docking solution. They provide reliable control in tight marinas and reduce the likelihood of accidental damage. Key advantages include quiet operation, thermal protection for safe use, and a broad choice of models to suit different vessels and budgets.
Bow PRO thrusters
Bow PRO thrusters are an advanced evolution of DC thrusters, featuring brushless motors and fully proportional control. This allows you to precisely adjust thrust instead of relying on simple on/off inputs, resulting in smoother and more accurate manoeuvring. They are digitally controlled and include built-in protection systems for added reliability.
They are well suited to boaters who want enhanced control and longer run times, particularly in demanding docking conditions or when operating short-handed. Easy to install and compatible with existing systems, they offer benefits such as maintenance-free operation, quiet performance, and features like 'lock-and-hold' control for added convenience.
Bow PRO Boosted thrusters
The Bow PRO Boosted series adds an integrated DC-to-DC smart charger to the Bow PRO platform. This allows the thruster battery bank to be charged from a different onboard voltage supply, ensuring efficient energy management and optimal battery performance. These thrusters deliver high thrust outputs ranging from 57 to 420 kgf.
They are ideal for boats with more complex electrical systems or higher power demands. The built-in charging system simplifies installation and keeps batteries in peak condition. Key advantages include powerful performance, extended runtime, and improved energy efficiency without the need for additional charging equipment.
Hydraulic Bow Thrusters
Hydraulic bow thrusters are built for demanding applications where high power and continuous operation are required. Instead of electric motors, they run on a vessel’s hydraulic system, delivering strong and consistent thrust (55–550 kgf) with high flow rates and pressure capabilities.
They are ideal for larger vessels or commercial applications where reliability is critical. With no electrical components at the thruster itself, they reduce potential failure points and require minimal maintenance. Key advantages include continuous duty capability, exceptional durability, and the ability to integrate with existing onboard hydraulic systems.
Rim Drive thrusters
Rim drive thrusters use an innovative design where the propeller itself forms part of the electric motor, eliminating the need for a central shaft and gears. The motor is built into the tunnel, resulting in smooth, efficient, and extremely quiet operation, with a protective ring to reduce cavitation.
They are ideal for boaters who prioritise silence, efficiency, and low maintenance. Suitable for a wide range of vessel types, these thrusters offer near-silent performance, minimal vibration, and fewer moving parts. Key advantages include exceptional quietness, improved safety, and long-term reliability.
Ignition-Protected thrusters
Ignition-protected thrusters are specially designed for use in environments where explosive gases may be present, such as engine compartments with petrol engines or fuel systems. They feature sealed, watertight motor housings that prevent fumes from entering and igniting.
These thrusters are essential for safety-critical installations and comply with strict marine safety standards. They are suitable for both bow and stern use and come as complete installation packages. Key benefits include enhanced safety, regulatory compliance, and dependable performance in hazardous conditions.
Retractable thrusters
Retractable thrusters are designed for boats where a conventional tunnel thruster cannot be installed due to shallow draft or hull shape. The unit is housed inside the hull and lowers into the water only when needed, then retracts when not in use.
They are particularly popular on sailing yachts and performance boats where reducing drag is important. Key advantages include suitability for shallow hulls, reduced drag when retracted, and efficient thrust when deployed. They also feature automatic operation, safety protections, and easy integration with onboard control systems.
Quick comparison of Vetus bow thruster types
3. HOW TO SELECT THE CORRECT THRUSTER
A bow thruster produces lateral thrust to move the boat sideways - this is measured in kilograms of force (kgf). To achieve reliable performance in varying conditions, it must generate sufficient thrust to move the vessel easily. The location of the tunnel is crucial to its effectiveness: the further forward towards the bow the thruster is positioned, the greater the turning leverage a the more effective the bow thruster.
Similarly, the force exerted by the wind on the boat depends on factors such as wind speed, wind direction, and the vessel’s lateral windage area. As wind speed increases, the force it imparts increases exponentially: a balance therefore has to be struck between a bow thruster which will still provide some benefit in very windy conditions (Beaufort scale 8 and above) but will not be over-powered on a calm day.
The ease with which the boat can be moved may also depend on the hull design: for example, a long-keel yacht will require more force to move it through the water compared to a shallow-draft powerboat.
It is possible to calculate the force required from the bow thruster by using the following formula:
Torque (Nm) = wind pressure (N/m²) x wind draft (m²) x reduction factor (usually 0.75) x distance from the centre of effort to the pivot point (m)
Force (N) = Torque (Nm) / distance between the centre of the bow thruster and the pivot point of the boat (m)
While this can be used to calculate the correct size of thruster, it is usually possible to estimate the power of bow thruster required using the table in section 4, below.
4. BOW THRUSTER SELECTION CHART
Once you have decided on the type of Vetus bow thruster you require, the correct model can be selected using the chart below.
Where there is more than model of bow thruster available for your boat, it is advisable to opt for the larger model to give you more power in windy conditions, but there may be other factors to consider, for example you may wish to opt for a smaller tunnel diameter which make installation simpler.
Similarly, it may be type of boat should be considered: for example, a boat with large topsides or a long keel would usually require a bow thruster with more power than a shallow-draft powerboat with low topsides.
If you do wish for assistance choosing the correct bow or stern thruster for your boat, please contact us or call us on 01248 811 001.
Please note that Vetus bow thrusters are named for the force they produce: while the power of the motor in kW (or horsepower) may be used as a guide, it is possible that different models of thruster may use the same motor but produce a different amount of thrust - so always compare bow thrusters based on thrust rather than motor power.