The outstanding feature of all servo-pendulum systems is their huge servo force, strong enough given a good transmission arrangement to steer boats of 18 m / 60 ft and 30 tonnes. Under normal conditions a servo-pendulum gear will be able to steer the boat as long as forward progress is being made and the flow past the hull is sufficient to push the pendulum rudder one way or the other. Servo-pendulum gears generate several times the force of a simple auxiliary rudder system.
One drawback of this type of gear is the care required to set up the steering lines properly. Poorly arranged steering lines reduce efficiency and can even disable the whole system. Because line travel is limited to 25 cm, longer transmission paths unavoidably impair steering performance. If the system keeps no line travel in reserve during normal operation, it is inevitable that the rudder will eventually lose control in demanding conditions. Transmission is always worse with wheel steering; the degree of deterioration depends on the characteristics of the system in question.
Practical steering force transmission to a centre-cockpit wheel is very difficult because the transmission paths are so long. The use of stainless steel wire offers some improvement here, but entails other problems (e.g. turning block wear).
There is no way of using a servo-pendulum gear for emergency steering: it is impossible to fix the pendulum arm in place, and in any case the rudder blade lacks sufficient area to
provide acceptable steering in difficult conditions. A 0.1 m / 1 ft pendulum rudder blade could not possibly be up to steering a boat in seas rough enough to break a main rudder. Servo-pendulum gears are not normally designed to handle the loads associated with emergency rudder use, so any system which is nevertheless recommended by its manufacturer for this purpose will need substantial structural reinforcement to stabilise the pendulum arm.
The Sailomat 601 has to be fixed in place using lines at the sides which are tied to the pushpit. The shaft and rudder are strengthened to ensure that the rudder does not break away when the lines are in place, but this reinforcement means the rudder and stock are heavier for self-steering operation (see Sensitivity).
The pendulum rudder on a MONITOR gear can be replaced with a larger emergency rudder, the shaft then needing 6 lines for lateral stability.
V vane servo-pendulum systems: Hasler, Schwingpilot.
H vane servo-pendulum systems:
a. bevel gear yaw damping: Aries, Fleming, Monitor, Windpilot Pacific;
b. other forms of yaw damping: Cap Horn, Sailomat 601, Navik, Atoms.
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Lets start by identifying what exactly certain boats are. Sometimes the terminology can get lost on beginners, so well look at some of the most common boats and what theyre called. These boats are exactly what the name implies. They are meant to be used for fishing. Most fishing boats are powered by outboard motors, and many also have a trolling motor mounted on the bow. Bass boats can be made of aluminium or fibreglass.