Frequently Asked Questions

 

Which types of boats can benefit from ShaftPTO installation?

ShaftPTO generator is a shaft power take off system. Therefore only 2 conditions need to be met:
* Propeller shaft that rotates when vessel is under sail
* appr. 10cm / 4 inches (12cm / 5 inches for ShaftPTO-800) of shaft length available to install the unit
It can not be installed on boats equipped with SailDrives and/or Feathering props.

 

How complex is the installation process?

Installation process usually takes less than an hour and can be accomplished by a DIY cruiser. Mechanical part: "Clamp on" style. Install split pulley on the shaft using 2x bolts. Secure with 2x set screws. Position the generator unit over the pulley and secure with 4x screws. Done.
Electrical part: secure regulator and DC-DC charger on a bulkhead and attach positive(+) and negative(-) wires to your battery bank.

 

How much power and at what boat speed ShaftPTO generates?

ShaftPTO generator "kicks in" as soon as your propeller shaft begins to rotate steadyly. In most cases ShaftPTO generator will reach full rated output at just 5 kts under stail (appr. 200 RPM on the shaft). Current output is regulated by a DC-DC charger.
ShaftPTO-250 is rated at 18 amps at 12 volts, approximately 250watt continious output. 5kWt in 24 hours.
ShaftPTO-800 is rated at 30 amps at 24 volts, approximately 800watt continious output. 12kWt in 24 hours.

 

Can it damage my gearbox / shaft bearings?

Nigel Calder answerd this question in "Boat Mecnahnical": "quote from the book comes here describing potential damage to the gearbox and other componnents ". Indeed, the load imposed by is neglegable comparing to what boat propeller and shaft bearings are designed for.
For example, ShaftPTO-250 Dynoload is just 2Nm. So the true answer is: No, ShaftPTO generator is not "strong" enough to place any noticable load on boat shaft / gearbox.

 

Can is slower my boat?

Yes, technically ShaftPTO generator is an electrical break therefore there will be some penalty.
Expect to slow down by 0.1-0.2 kts of drag at 6 knots boat speed (1.5 - 2.0%) at full rated output.
ShaftPTO generator can be depowered for race conditions.

 

Maintenance / Service intervals?

ShaftPTO generator are made to last in harshest environment - oil, dirt and salt water is not a concern. Expect the same level of maintenance that your alternators nees - practically nothing until the belt wears out or bearings kaput.
ShaftPTO generator is assembled with high quality parts: oil impregnated brass and ceramic bearings, 316 stainless steel, heavy duty anodyzed aluminum frame.
We still recommend a visual inspection after every ocean crossing or annually