For boats fitted with a rudder with speed not exceeding 25 knots, the torque of the rudder or rudders is calculated according to following formula and corrections.
|It must be known that the torque necessary to manoeuvre a boat depends on:
Torque Calculation Formula for Speed below 25 Knots
C = S x [ (0.4 Lg) – Lc ] x V² x K
Once the torque is known, the appropriate cylinder is selected and one or two manual pumps will be added.
Note: If the selected pump has a higher flow rate in order to reduce the number of turns lock to lock, it will be necessary to use a steering wheel with the maximum recommended diameter.
For pleasure boats with planing or semi-planing hulls and speed exceeding 25 knots, the cylinder may be selected by using the chart below:
|Length of Hull||Cylinder Type – 1 Rudder||Cylinder Type – 2 Rudders|
|8 metres||VHM 40 DTP||VHM 32 DTP|
|10 metres||VHM 40-254||VHM 40 DTP|
|12 metres||VHM 40-254||VHM 40 DTP|
|14 metres||VHM 50 DTP||VHM 40-254|