SEDONA F25 - Hydraulic Steering; Ventilation

4. Hydraulic Steering (not shown):
With this system the steering wheel movement pumps hydraulic uid through lines to a cylinder
which transfers movement to the engine rudder. Sedona uses Sea Star for itʼs Hydraulic Steer-
ing System. This steering system makes it easier to control the boat because the steering wheel is
easier to turn. Sedona uses hydraulic steering on the performance package because of higher engine
horsepower usage.
For additional information please refer to the Sea Star ownerʼs manual provided with your
Sedona ownerʼs packet (if applicable).
Ventilation:
Pontoon boats are characteristically prone to ventilation due to being semi-displacement boats and
also due to the size and weight of the typical pontoon. Choosing the correct engine and propeller
will help to eliminate nearly all ventilation issues (assuming normal load distribution).
What is ventilation?
Ventilation is the result of air being introduced into the water through which the propeller is turning.
When air is introduced, the propeller loses its grip on the water and begins to “slip” excessively.
This is all very similar to a car tire loosing traction and slipping on ice or snow. In a pontoon boat,
the result is an immediate reduction in
speed.
When does ventilation it occur?
Ventilation usually occurs when the boat is being steered into a turn under power. Pontoons travel
through the water in a very efcient and clean manner when they are traveling in a straight line, but
when they are put into a turn, they draw a lot of air into the water. The result is “dirty water” which
is very turbulent and full of air bubbles. The boatʼs engine is forced to run through this dirty water.
What can be done to reduce ventilation?
The best defense against ventilation is to select an engine that best matches your pontoon boat.
For the best performance, large pontoon boats (22ʼ +) and boats with 25” pontoons should be pack-
aged with engines that have large gear cases. Likewise, Mercury Bigfoot and Yamaha High Thrust
models are also well suited to larger boats even in lower HP applications. Engines with large gear
cases are able to turn larger diameter propellers that help to maintain a better grip on the water dur-
ing acceleration and in turns.
Some other helpful suggestions and things to remember concerning ventilation:
Adding cup to a propeller or switching to a stainless steel propeller that is usually already double
cupped will generally reduce ventilation.
Excessive trim can and will cause ventilation. Trim does not affect pontoon boats as much as it will
other types of boats.
Sedona has found that in certain applications a Doel Fin, or equivalent, can help to reduce ventila-
tion.
Using the propeller guide from the engine manufacture and their technical advise can be very help-
ful. Sedona has experienced that some engine manufactures have propellers designed specically
for pontoon use, and few after market propeller makers are starting to build propellers for pontoon
applications.
Extremely quick maneuvers, such as, hard turning, etc., will cause ventilation.
Because of the seating on pontoons it is very important to distribute the weight and passengers
evenly throughout the boat. If the pontoon is loaded nose heavy, the boat will experience ventila-
tion. This is even more important on sh model pontoons because of trolling motors, batteries, etc.,
mounted to the extreme front of the boat.
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