Athene

Motor and Propeller

A long keel offers many advantages on a seagoing vessel. Besides course stability and pleasant sailing, it also allows deep installation of the engine.

The engine, a Yanmar 4JHE with 44 hp, consumes just under 3 liters of diesel per hour at a cruise speed of 6 knots. Because of the deep installation below the waterline, the motor is silent. A heavy and well-insulated engine cover dampens the noise well. We have improved the machinery by installing a flexible coupling (Centra-Flex), which absorbs the vibrations of the engine and shaft system. The 1500 mm long shaft (30 mm diameter) is water-lubricated. It seals the shaft with a packed gland and lubrication gun. This sealing is far from high-tech, but absolutely reliable, can be easily readjusted and maintained if required.

Until 2005 we sailed with a fixed propeller and found it a nuisance. In brief: Relatively loud when sailing, poor rudder effect. Often we had the feeling that the boat could sail faster, but is slowed down. Even occasional sailors as guests on board noticed this. Stopping up or backward was often only possible with full throttle. A nuisance all along the line …

… and then the Varioprop was mounted.

  • The light wind characteristic has improved. Even our 12-ton boat, especially close to the wind.
  • The boat is very balanced on the rudder (enlarged lateral plan, no turbulence).
  • Relief of the autopilot.
  • A fixed propeller catches none ropes or nets!
  • Haven of tranquility
  • And last but not least, maneuvering in the harbor is much easier due to the strong backward thrust.

SPW Propeller Supplement Spring 2014:

 SPW was already concerned when designing the propeller that the wide “dead wood” – approx. 120 mm – could lead to considerable turbulence and thus to reduced performance and increased noise development. The proposed solution was baffle plates. Installed in 2013, we heard the difference right from the start. The propeller hummed full and muffled; the faint unpleasant noise of past years had disappeared. The boat sails 0.3 Kn. faster at the same engine speed. The surprise: Even under sail the boat has increased its speed. 7,5 Kn are well feasible with half-wind (Lübeck bay, on both bows to calculate possible current, GPS data). 0,3 Kn is not much, but enough to keep up with modern boats of the same size and type Sailing is more fun.

The propeller has been in use for 12 years. The Varioprop works excellently is reliable and has often been recommended by us. In short, we don’t want to miss this propeller anymore. If you want to know more, here are the data: ø 18″ x 12″ x 13″ / ISO 30 / 1:10 – RH