Trim Tab Hard Lift for automatic trim tabs

the new compact RocketFlap Lite is a marine trim tab system
INVENTED to boost runabout hulls onto the plane automatically

hard lift ...

Simply by utilizing a boats own forward motion while accelerating onto the plane, downward deployed trim tabs, retarded by rams, are gradually pushed up by the resultant water pressure achieving the desired LIFT to assist the boat onto the plane effortlessly ...

Hard Lift over a very short duration but only while accelerating onto the plane.

Early development of the RocketFlap fully automatic hands free trim tab system.

Any addition of Trim tabs to a boats transom provides increased surface area and therefore additional lift. Simply installing a pair of movable tabs dampened by moderate springs will provide some lift. If, however, you want an automatic system to produce meaningful, hard lift then the tabs movement needs to be effectively retarded .

Hard Lift is a term we use to describe the quality of lift that results from conventional electro/hydraulic or fixed trim tab systems provide. An automatic, dynamic system, such as RocketFlap (or any other similar automatic type of system) cannot achieve the same like for like amount of Lift.

However, a key design goal was to get as close as possible to the hard lift qualities of conventional/ fixed trim tab systems in order to create a system that applies genuine lift over a very short duration, in a practical and workable way, to effortlessly assist a boat out of the water and onto the plane..

Initial tests of the RocketFlap system were performed on the red 17ft VIP 1700 Vision shown in the the picture. At the time the standard engine options for the boat was the OMC Cobra 3ltr or 2.3ltr TKO 4 cylinder units. For more power though, the boat below was specified with the V6 Cobra 205 unit.

17ft VIP Vision without tabs

Once on the plane this was a very good boat, effortlessly exceeding 50mph and very at home in coastal waters. However the 17ft length wasn't sufficient to support the additional weight of the V6 engine resulting in poor 'out of the hole' performance.

The concept of the RocketFlap system is very simple;

Use a pair of trim tabs to get a runabout sized boat 'out of the hole' and onto the plane, fully automatically and 'hands free' - without the need of motors, wires , pipes, rocker switches etc...

Initial testing was simply about determining exactly how a pair of fixed trim tabs would affect the VIP Vision's ability to get on the plane.

Without going to the expense of installing a full hydraulic system, and all that involved, a crude pair of fixed trim tabs were manufactured . They measured approximately 6" x 8" fitted with butt hinges and struts capable of two positions - 2 degrees and 20 degrees down when installed on the transom.

Because the relative area of the tabs was quite small, even for a 17ft hull, it was expected to get the most effective test results from the 20 degree down position. For a first outing on the estuary though, caution was used so the tabs were fixed at the 2 degrees down position.

Despite having only two degree of down angle, the result was remarkable; a gentle application of throttle and the boat was on top of the water and away. It was completely effortless for the engine, and totally transformed the boat.

However, once up and running the throttle had to be quickly pulled back because, now fully on the plane with the tabs still providing tremendous lift, the bow was being stuffed into the water causing undesirable and potentially dangerous 'bow steer'. Trimming the engine leg all the way UP, even using the trailer button (creating a huge rooster tail), had no effect on the 2 degree fixed downward tabs - the bow was firmly plugged.

The test, however, was a complete success, and outlined the basic requirements for a fully automatic trim tab system;

a system with a meaningful burst of lift (later to be known as HardLift) for a very short duration while transitioning to plane after which the system had a neutral effect on the boat. All done automatically - the Rocket Flap.