Speed of vessel – what is the maximum permissible ?
Above 17.5 knots the performance falls off or the output stops due to the unit starting to surface and suck in air. The maximum speed can be considerably less in rough waters. For higher speed vessels and some catamarans it is necessary to add a weight to the tow tube to keep it submerged at higher speeds. A 2 kilo weight added to the tow tube (a shaft anode is usually used) will increase the speed to 17+ knots for faster vessels. A high speed impellor is available for faster catamarans when the maximum speed is circa 20 knots.
