A trim tab for mounting the transom of a boat has an upper surface and an undulating bottom surface with down-turned flaps on opposite sides of the tab. The trim tab is formed of a molded composite material. The top surface includes a hinge platform at its forward end and mount platform at a rearward end. The trim tab tapers from a minimum thickness at its leading end to a maximum thickness at its trailing end. The shape of the bottom surface and the down-turned flaps provide a bottom surface area with enhanced lift characteristics.
1. A trim tab comprising:
a front end;
a rear end;
a first side;
a second side;
a top surface extending between the front end and the rear end; and
a bottom surface extending between the front end and the rear end, the bottom surface including a longitudinally extending convex central region and first and second concave channels extending longitudinally on opposite sides of the convex central region;
a plurality of transverse ribs on the top surface;
a plurality of longitudinal ribs on the top surface extending a substantial portion of the length between the front end and the rear end; and
wherein the plurality of longitudinal ribs include first and second longitudinal ribs on the top surface above the first and second concave channels, respectively.
2. The trim tab of claim 1 and further comprising:
a first side flap extending longitudinally along the first side; and
a second side flap extending longitudinally along the second side.
3. The trim tab of claim 1 , wherein first and second side flaps are downturned and have a greater height at the rear end than at the front end.
4. The trim tab of claim 1 and further comprising:
a hinge connection platform on the top surface adjacent the front end; and
a mount connection platform on the top surface adjacent the rear end.
5. The trim tab of claim 1 , wherein the plurality of transverse ribs include transverse ribs adjacent the front end, and transverse ribs adjacent the rear end.
6. The trim tab of claim 1 , wherein the plurality of longitudinal ribs include at least one longitudinal rib on the top surface above the convex central region of the bottom surface.
7. The trim tab of claim 1 , wherein the trim tab is a one-piece molded body of a polymeric or composite material.
8. The trim tab of claim 1 , wherein the top surface includes a concave region overlying the convex central region of the bottom surface.
9. A trim tab comprising:
a front end;
a rear end;
a first side;
a second side;
a top surface extending between the front end and the rear end; and
a bottom surface extending between the front end and the rear end, the bottom surface including a longitudinally extending convex central region and first and second concave channels extending longitudinally on opposite sides of the convex central region; and
wherein the convex central region is tapered from a wider and thinner forward portion adjacent the front end to a narrower and thicker rearward portion adjacent the rear end.
10. The trim tab of claim 9 , wherein each of the first and second concave channels is tapered from a narrower and shallower forward end adjacent the front end to a wider and deeper rearward end adjacent the rear end.
11. A trim tab comprising:
a body having a front end, a rear end, a first side, a second side, a top surface, an undulating bottom surface, a first side flap extending downward along the first side, and a second side flap extending downward along the second side;
wherein the undulating bottom surface includes a longitudinally extending convex central region, and longitudinally extending concave channels on opposite sides of the convex central region; and
wherein the convex central region is tapered from a wider and thinner forward portion adjacent the front end to a narrower and thicker rearward portion adjacent the rear end.
12. A trim tab comprising:
a body having a front end, a rear end, a first side, a second side, a top surface, an undulating bottom surface, a first side flap extending downward along the first side, and a second side flap extending downward along the second side;
wherein the undulating bottom surface includes a longitudinally extending convex central region, and longitudinally extending concave channels on opposite sides of the convex central region;
a plurality of transverse ribs on the top surface; and
a plurality of longitudinal ribs on the top surface extending a substantial portion of the length between the front end and the rear end, wherein the plurality of longitudinal ribs include first and second longitudinal ribs on the top surface above each concave channel, respectively.
13. The trim tab of claim 12 , wherein the top surface includes a concave region overlying the convex central region of the bottom surface.
14. The trim tab of claim 12 , wherein each of the concave channels is tapered from a narrower and shallower forward end adjacent the front end to a wider and deeper rearward end adjacent the rear end.
15. The trim tab of claim 12 and further comprising:
at least one longitudinal rib on the top surface above the convex central region of the bottom surface.
16. The trim tab of claim 12 , wherein the plurality of transverse ribs include transverse ribs adjacent the front end, and transverse ribs adjacent the rear end.
17. The trim tab of claim 12 , wherein the body is formed of one of: molded polymeric material, molded composite material, and stamped metal.
18. The trim tab of claim 12 and further comprising:
a hinge connection platform on the top surface adjacent the front end; and
a mount connection platform on the top surface adjacent the rear end.
19. The trim tab of claim 12 , wherein the flaps extend downward and outward.
20. The trim tab of claim 12 , wherein the flaps are oriented at a depression angle of about 70°.