Understanding Wing Engines: Powering Your Boat's Performance

A wing engine is a small, low-power, completely separate propulsion system, independent of the main engine, with its own shaft and propeller. It is often used as a get-home engine, providing emergency backup power in case the main engine fails. Wing engines are typically much smaller than the main engine, with enough power to push the boat at 4-5 knots in normal sea conditions. They have their own electrical systems and fuel supply, and are usually located off-center with a folding prop. While they provide peace of mind for boat owners, wing engines also come with drawbacks, including additional maintenance, space constraints, and the need for regular exercise to ensure reliability.

Wing engines are a form of auxiliary propulsion for single-engine boats

Wing engines are much smaller than the main engine but have enough power to push a boat at 4-5 knots in normal sea conditions. They have their own electrical systems and fuel supply, and spin a separate shaft and propeller. This separate shaft and propeller can be useful if the main running gear is damaged in a collision.

Wing engines are often used to power thrusters, pumps, and other equipment. They can also be used to power a boat's hydraulic gear, such as stabilizers, windlass, and a hydraulic bilge pump, ensuring that the wing engine is regularly exercised.

Wing engines have their own advantages and disadvantages. On the one hand, they provide redundancy and peace of mind for boat operators. They can also be used for manoeuvring in tight spaces, such as when docking or anchoring. On the other hand, wing engines take up additional space in the engine room, require more maintenance, and increase the cost and weight of the boat.

Some boat operators choose not to install a wing engine, relying instead on the reliability of modern diesel engines and carrying a full supply of spare parts.

They are small, low-power, and independent of the main engine

A wing engine is a small, low-power, completely separate propulsion system, independent of the main engine. It usually has its own shaft and propeller, electrical system, and fuel supply.

Wing engines are typically much smaller than the main engine, but they have enough power to push a boat at 4-5 knots in normal sea conditions. They are often used to navigate into and out of harbours or marinas, and then the main engine is used for the long trip. They are also used to manoeuvre boats into a slip or out of a tight anchoring situation.

Wing engines are also used to power thrusters, pumps, and other equipment. They can be used to power the vessel's hydraulic gear, such as stabilisers, windlasses, and hydraulic bilge pumps.

Wing engines should be regularly maintained and exercised to ensure they remain reliable.

They have their own shaft, propeller, electrical and fuel systems

A wing engine is a small, low-power, completely separate propulsion system, independent of the main engine. Wing engines have their own shaft, propeller, electrical and fuel systems.

The wing engine shaft passes through the hull via a stuffing box and shaft log assembly, just like the main engine. However, unlike most main engine shafts, which pass through the keel, the wing shaft relies on a strut for support. The strut and propeller are susceptible to damage or fouling from floating or semi-submerged debris, fishing gear, lines, and nets. The outboard shaft also impacts the vessel's tracking, requiring a steering offset of up to 20 degrees.

Wing propellers are typically of the folding or feathering variety to reduce drag. If not properly maintained, they can fail to deploy when needed, especially if used infrequently. It is important to regularly inspect and maintain the wing running gear, ensuring the shaft turns freely and treating the propeller with an antifoulant to prevent seizure and drag.

The wing engine should have its own starting battery, shift and throttle controls, and raw water supply. Builders often address the fuel source issue by installing a dedicated wing engine fuel supply, ensuring independence from the main engine. The wing engine fuel reserve should be used or "turned over" periodically to maintain fuel quality.

They are used to navigate harbors, slips, anchoring situations and for manoeuvring

Wing engines are used to navigate harbors, slips, and anchoring situations and for manoeuvring. They are a form of auxiliary propulsion fitted to single-engine trawler yachts, essentially transforming a single-engine vessel into a twin-screw vessel. This provides added manoeuvrability in tight spaces, such as when docking or anchoring.

Wing engines are typically smaller than the main engine but have enough power to push the boat at 4-5 knots in normal sea conditions. They have their own electrical systems, fuel supply, shaft, and propeller. The propeller is usually a feathering or folding type, which can be used to reduce drag when the engine is not in use.

The benefits of a wing engine are enhanced manoeuvrability and redundancy in case of a main engine failure. However, they also have some drawbacks, including the additional space, maintenance, and cost associated with having another engine.

To ensure the wing engine is reliable when needed, it should be regularly exercised. This involves running the engine at least once a week and ensuring it reaches operating temperature. This helps prevent issues such as the feathering prop refusing to un-feather due to lack of use.

Some boats use the wing engine to power other equipment, such as hydraulics for bow thrusters, windlasses, and alternators, ensuring the engine is regularly used and providing additional benefits.

They are also used to power thrusters, pumps and other equipment

A wing engine is a small, low-power, completely separate propulsion system, independent of the main engine. It has its own shaft and propeller, electrical and fuel systems. Wing engines are often used to power thrusters, pumps and other equipment.

Wing engines are used to power bow thrusters, which are used to manoeuvre boats into a slip or out of a tight anchoring situation. They can also be used to power windlasses, which are used to lower and raise anchors.

Wing engines can also be used to power hydraulic pumps, motors, and controls, which are commonly used for stabilisers, thrusters, cranes, and other accessories. This arrangement is known as a generator hydraulic drive. The generator's engine is used to power a hydraulic pump, which can then be used to power a hydraulic motor that propels the vessel. This system is well-understood and easily serviced, making it a practical option for auxiliary propulsion.

In some cases, wing engines have been set up to operate large alternators for more effective and efficient battery charging. This ensures that the wing engine is used regularly and provides a backup power source for the vessel.

Frequently asked questions