Sleipner Pro DC SEP210, Руководство по установке, Страница: 10 / 28

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2713 20 2022
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SEP 210
MG_0003
High water force
while underway
High water force
while underway
from wave contact
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Water Deflection
MC_0003
1. A possible problem in sail boats or fast powerboats is that a non-rounded surface can generate drag from the back face of the tunnel, as it creates
a “flat” area facing the flow of water.
This problem can be solved in two different ways, depending on what is possible or easier to perform.
2. The best solution which generally reduces the most drag is to make a recess in the hull at the back of the tunnel. As the back face is removed
water can flow freely past the tunnel entry. The depth and shape of this recess will depend on the boat and the angle facing up/ down aft of the
tunnel insert. Normally it is angled slightly down because of the water flow on this area.
3. Making a deflector/ spoiler in front and underneath the tunnel can also reduce damage to the thruster and drag. The deflector/ spoiler will push
the water flow out from the hull so water can pass by the back face of the tunnel. The shape and size of this deflector/ spoiler will depend on the
hull shape. The easiest way of making the deflector/ spoiler is to retain a part of the lower forward area of the tunnel while installing the tube. Use
this area as support to mould a soft curve/spoiler shape from the hull.
4. The thruster propeller can spin (passively) producing noise while sailing or cruising as water is forced through the tunnel. Water-flow directed
through the tunnel at high speeds, during turning or as the boat bumps waves while underway can also damage the thruster.
(NB: As a rule, you should not see the back face of the tunnel when standing directly in front of the boat looking aft.)