42
Positioning the hydrogenerator on the transom
Correctly positioning the hydrogenerator is crucial for optimizing its performance.
The following criteria must be respected during the installation :
•
Immersion depth :
The hydrogenerator is supplied with a submerged aluminium leg measuring 610 mm (24 in) or
970 mm (38 in). The recommended depth between the surface and the propeller axis is 300 mm
(12 in). The greater the depth, the farther the propeller will be from the wake of the hull, and the
better the performance of the hydrogenerator. However, the most important the lever arm is, the
greater the force on the mountings and during lifting will be.
We recommend a length of 970 mm (38 in) as a satisfactory compromise for most monohull
installations.
The 610 mm leg is suitable for very large monohulls with a device installed on each side.
•
Flow quality :
The quality of water flow is a key element for obtaining satisfactory power output.
N.B. : Do not position the hydrogenerator directly in the wake of an appendage
or too close to a saildrive.
Wherever possible, position the hydrogenerator several inches to the side, in order to offset it from
the rudder, the propeller or other appendix.
Example of installation with the longer leg (970 mm / 38 in) :
Installation on a 10 m (33 ft) Figaro II heeling at 20° (CFD by CRAIN)
The length of 970 mm is enough for it to be immersed properly during listing because the loss of
speed due to the wake is about 5%.
