Thrusters
Anyone who has tried to get into a slip with a side wind blowing has probably wished for thrusters. On smaller boats with a single screw, it makes up for the disadvantage of not having two propellers to move the stern around. For solo launches, a remote control makes it a snap to undo bow and stern lines while keeping the boat against the finger pier. Electrical units are available for 30-50 foot boats; hydraulic power is usually recommended for larger vessels.
Leif Erickson discusses key issues in thruster selection and installation.
Listen to “Dock like a pro with thrusters” now.
- Thruster Types
- Product
- Purpose
- Range
- Structure
- Attachment
- Stabilizers
- Placement
- Remote Control
Thruster types
There are two basic kinds of thrusters: hydraulic and electric. Hydraulic thrusters are the most expensive; electric thrusters the most economical. In the case of hydraulic thrusters, although more expensive at the onset, their durability saves in the long-run, and they have more horsepower to push water through the tunnel. Conversely, electric thrusters may cost less up front, but in the long run, it may not be the best choice. In a short period of time the engine will get very hot, and fuel or batteries will need to be replaced because of their intense electrical demand.
Product
Our experience has been that American Bow Thrusters make a superior product. They take great care to ensure that the thruster is in proper proportion for your yacht. They have a system that considers the windage of the vessel, as well as the diameter of the propeller. Customer satisfaction is consistent with their product. Many captains are very pleased with their choice of the hydraulic thrusters from American Bow. Townsend Bay Marine has installed hundreds of their thrusters over the years.
Purpose
Powerful thrusters are a great aid in having more control. Most people install thrusters so they can handle the boat with their spouse alone. A lot of people complain about having to dock in side winds. The more power and control readily available, the more authority you will have navigating, including sideways and backing down. Your options open up dramatically with thrusters.
Range
The variety of boats that have thrusters is getting wider and wider. Even owners of smaller boats are installing thrusters these days. They are the single most popular yacht accessory today. Thrusters are not only for powerboats anymore. There are fantastic thrusters for sailboats that move up and down and retract into the hull so that there is no hole to impair performance. So if you like versatility with your sailboat, thrusters could enhance your yachting experience.
Structure
Most, but not all, vessels can accommodate thrusters. Some wooden boats might be restrictive due to their construction methods. For an aluminum boat you would put an inner and outer backing plate on the hull. For a fiberglass boat the inner and outer structural tubes are heavily scheduled metal or very thick fiberglass, so the installation process would add considerable strength to the front of the boat.
Attachment
Many boat owners are not only attaching thrusters to the bow of the boat, but also to the stern. Most stern thrusters are an external attachment behind the transom. Nordhavn puts theirs under the transom. It is easiest to just place the thrusters in the back. The structure of your boat is surely strong enough to handle nearly any thruster, no matter the horsepower. Nearly any boat can take thrusters, even metal boats. In that case, the thruster can be welded to the transom.
Stabilizers
Thrusters exert great force that can be tricky to handle. There are tables and charts you can use to gauge what size thruster you should use for your boat. Always err toward the more powerful, and hydraulic is the best way to go. You will have much more freedom for future projects for your yacht.
Placement
It is important to place the bow thruster appropriately. It needs to be far enough forward that the tunnel isn't too long and the thruster has good leverage to rotate the bow. On the other hand, it has to be deep enough under the water line to avoid cavitation. Usually the location of the bow thruster is chosen for you--there is a collision bulkhead behind the chain locker and aft of the bulkhead the tankage usually begins. Normally the space between the collision bulkhead and the tankage is the only suitable place for the bow thruster. While they are relatively low maintenance it should be accessible and ventilated to keep it dry. Ideally, you will be installing a hydraulic thruster, as they are the easiest to manage.
Remote Control
There are a few companies that supply a remote control system with the thruster. It is a simple hand-held remote that you can stand on the dock and move your yacht. When you are single handing a remote comes in very handy. Just walk to the end of the dock and bring the stern in, undo your bow line, step on board and you’re out of the harbor in no time at all.