Bow thrusters: how they work, which ones to choose, and prices

Bow thruster and maneuvering propeller–how do they work? With relative ease today, even an efficient bow thruster or maneuvering propeller can be mounted on an “old” boat. These accessories will ensure you have good directionality of the boat even when hit by side wind (or current) and the ability to rotate the hull in tight water spaces.

Bow thruster: how it works, which ones to choose and prices

Bow thrusters are divided into three types:

• the more popular and inexpensive fixed type ducted models. In this case, the keel of the boat is pierced from side to side, as far forward as possible, and a tube containing a transverse propeller is installed that, depending on the given command, rotates left or right providing the required lateral thrust. The engine normally sits directly above the propeller and thus finds its place inside the hull.
• the vertical column retractables
• Concealed with rotating or parallel-arm mechanisms. In both of these systems,
  used on boats of a certain size, the propeller drops into the water when its use is required. Part of the keel is opened, and the propeller supported by a telescopic arm begins to operate. When use is over, it re-enters the hull and closes the “hatch” in the keel. The most common motorization for recreational use (up to 70 feet) is with an electric motor.

Easy to install and inexpensive only has the shortcoming of consuming a lot of energy, so be careful with batteries and always use them with the engine running. As for the propulsive propeller, the single propeller system with two propellers that can also rotate simultaneously in the same direction to offer more power with a smaller hull bore or double counter-rotating propeller is used. The latter makes it possible to improve thrust efficiency by reducing rotational phenomena in the direction of the propeller that decrease thrust.

BOW THRUSTER PRICES

Prices of bow thrusters (for a boat on 10/12 mt) range from 2000 to 3000 for electric models with fixed type system ducted or. To this cost should of course be added the installation costs, which are lower in case the work is done during the construction of the new boat, higher if work is done on a used hull. Costs vary widely, and we recommend asking for detailed quotes from multiple construction sites.

MAX POWER / COMPACT RETRACT

When Max Power introduced the first retractable maneuvering propeller in the late 1980s there was a real revolution in the sailing world. Today Max Power has a line of products that can meet the needs of boats from 35 feet and up, up to maxi yacht models. There are two electrically operated versions offered by the French company, the Compact Retract version, shown in the photo at right, is suitable for boats up to 50/55 feet, while the retractable line that is called Vip Retract, which is ideal for larger boats, is with vertical, non-tilting movement.

www.max-power.com

SIDEPOWER / SE25

The SE25 bow thruster (12V powered) is the newest addition to Side Power: it fits small to medium-sized hulls (the diameter of the “tunnel” is 110 mm) and also offers great installation flexibility,
as the thruster can be installed on the tunnel at any angle. It weighs 25 kilograms. It ensures low vibration and noise levels and is equipped with a self-lubrication system and for protection against galvanic currents.

www.saim-group.com/saim-marine

VETUS / BOW PRO BOOSTER THRUSTER

These thrusters have a truly “proportional” control (the propeller increases rotational speed in proportion to how far, left or right, you push the control joystick knob): in effect, the maximum peak absorption disappears with less stress on the batteries. What is new is the presence of a “booster,” which is a third connection that sends current to an internal engine charger and converts the 12V input into a 24V output current. Any secondary 24V battery bank can also be recharged from a 12V source, such as the engine’s alternator. This gives you a choice of 12 or 24 V battery banks. The built-in charger recharges the battery bank when the thruster is not in use.

www.vetus.com

CRAFTSMAN MARINE / THRUSTERS

A complete range of maneuvering systems for vessels up to 20 meters in size. Different models range from a thrust of 35 kgf to activate to the most powerful of 170 kgf. All motors are thermally protected, preventing improper use from creating overheating or depletion of energy resources. The motors run on 12 or 24 volts DC.

www.mzelectronic.it

LEWMAR / 110 TT TUNNEL THRUSTERS

Extremely easy to install, it needs virtually no maintenance: it has a five-blade propeller that can provide the same performance in both forward and reverse. The profile of the entire thruster is designed to cause as little friction as possible.

www.osculati.com

SIDE POWER / EX SERIES

Side Power’s EX maneuvering propeller has the great advantage of external installation, so you won’t have to drill heavy holes in the hull. An ideal retrofit solution, with power, depending on the model, ranging from 25 kg of thrust up to 180 kg. It can be installed both fore and aft, is self-cooling, and its special hydrodynamic structure means that, when sailing, it produces less friction than a traditional system which, using a through-hole, creates more turbulence. Double-propeller models also exist.

www.saim-group.com/saim-marine

QUICK / BOW THRUSTER

The Quick bow thruster range includes several models, with thrust performance from 30 to 300 kg, for boats up to about 98 feet. They are available with electric motor (BTQ) for fixed installations, with electric motor in retractable version (BTR/BTVR) and with hydraulic motor (BTQH). Quick maneuvering propellers can be mounted fore and aft thanks to the special tunnels that make the two different installations possible. BTR or BTVR retractable propellers are equipped with electromechanical systems that allow the propeller at rest to retract into the hull, safeguarding the hydrodynamic efficiency of the boat while underway.

www.quicknauticalequipment.com