The Lewmar series 400 – 600 hydraulic tunnel thrusters have been used on many yachts over the years. All of the designs are available in both marine grade alloy, or bronze. One of the most important features is that the hydraulic motor is mounted on the top of the drive gearbox, and within the hull. There are no hydraulic drive components in the water minimising the chance of leaks or pollution. This series can cope with powers of 35 – 100HP, and is suitable for sail or power vessels from 65 – 140ft (15 – 43m).