3B5: Trim Tabs
The boat is fitted with a set of
Bennett
Trim Tabs. These are wide “flaps” attached to
the aft end of the boat, under the swim step at the trailing edge of the hull, operated
hydraulically under the control of the skipper
by rocker switches with indicators at each
helm station.
At low speeds, up to approximately
six knots, the tabs do little, and should be left
in the “Bow Up” position (see below). But at
speeds over this range, the tabs begin to
take effect and will help the operator lower
the bow for more efficient cruising.
The best way to adjust the tabs is to
lower them while watching the “Speed”
indicator to get the highest speed at a given
throttle setting by adjusting “Bow Down”. If the tabs are “Bow Down” too much, the steering
will get mushy and speed may drop off a little, and the tabs should be adjusted “Bow Up” a
little. Note that it will take time to make these adjustments; when the buttons are depressed,
they need to be held 2-5 seconds each time for change to be felt and observed (the best way
to see the effect of the tabs is by the knot meter and by observing the height of the bow
relative to the horizon, most easily seen from the lower helm station).
Because the trim tabs are so large, THEY MUST BE IN THE FULLY-BOW-UP
POSITION WHENEVER THE BOAT IS TO BE OPERATED IN REVERSE, otherwise the great
water forces against the tabs may damage them severely, even tearing them off the hull!
Trim tab controls on helm panel. (Additional controls are at flybridge helm.)
Section 3B: Maneuvering Suggestions 3.6