The fin units provide the torque necessary to oppose the sea
onces tending to roll the vessel. The fins are deflected by
pneumatic cylinders operated by the pressure from the
amplifiers in the control unit. Each fin unit comprises the
following parts:
a- Fin
b- Base
c- Operating pneumatic cylinders
The fin is symmetrical hydrofoil haing a fiber glass skin
over a rigid stainless steel frame. The interior of the fin
is filled with light weight closed cell foam which gives the
fin a remarkable strength/weight ratio. The fin may be
inclined up to 24 degrees in either direction.
When the air pressure is applied to the pistons which deflect
the fin, the fin deflects until the water forces acting on it
are balanced by the piston forces. This arrangement of
balancing the sea forces against the force that deflect the
fin insures that the lift produced by the fin remains almost
constant over a wide range of operational speeds. This means
that almost constant over a wide range of operational speeds.
This means that it is not necessary to provide a control to
reduce fin angles at high speeds ( self adjustable variable
incidence fin ). Without fin angle/speed compensation the
efficiency of the conventional stabilizers would be
considerably reduced at speeds below cruising speed and there
would be a danger of overstressing the fin shaft at high
speed.
5)Bridge Control
This is simply an ON/OFF pneumatic switch together with two
gauges to monitor the air pressure on the driving mechanism.
When the switch is placed to ON position, the remote valve
mounted on the air tank would open to allow the air to flow
through the control unit. The two gauges are connected in
parallel to the gauges on the amplifiers of the control unit
and therefore monitor the pressure in the amplifiers from the
bridge.
