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16 A. TUNÇER, G.T. TAYYAR and Y. ÜNSAN
equivalent buoyant force supporting the vessel’s weight during planing. [3] But the lift force is
not only advantageous, since it mostly lifts the bow creating a trim angle by the stern.
Figure 2.2 Sample Planing Mono Hull Forms [3]
Constant trim of the high speed crafts cause not taking the full advantage of the thruster since
the propulsion will occur at a certain angle, not parallel to the water plane, as seen in Figure 2.3
Trim by Stern While Planing [4].
Figure 2.3 Trim by Stern While Planing [4]
3. Trim Tabs
Trim tab is a solution to aforementioned trim caused problem. Trim tabs basically eliminate the
trim but also with a pair of trim tabs (one on port side one on starboard side), one can easily
eliminate heel and yaw motions for a more comfortable ride. Trim tabs can be considered as
motion stabilizers in a way, thus inventions and designs leading to trim tab goes back until late
1800s. First developments were in favor of stabilizing the roll and pitch motions, then
specializing in high speed crafts lead to traditional and interceptor type trim tabs’ invention.
GiDB|DERGi Sayı 7, 2016
