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NAVIGATOR OPERATING MANUAL
NW Explorations
4Q: Running Gear
4Q1: Shaft Seal
The vessel is equipped with a dripless shaft seal that is lubricated by water from the engine; the seal should
be occasionally checked to be sure that there is not inappropriate water leakage. Adjustment should be rarely
required. If needed, contact the charter company.
4Q2: 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 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!
Trim Tab rocker switches.
Indicators at each helm show
the trim tab positions.