Re: Hydrofoil, trim tab, or prop ?
rgibber34;<br /><br />I love these friendly debate about Props - Hydrofoils - and trim tabs!<br /><br />Anyone who has read my comments before will know exactly what I am going to say, but I just can not resist. <br /><br />The basics are easy - <br />Props are designed to "propel".<br />Hydrofoils are designed to "Lift"<br />Trim Tabs are designed to "lift and control attitude".<br /><br />Some props are designed to propel and create some lift. Extra blades have a tendency to improve low end performance, but at the sacrifice of top end performance. Spinning more blades creates more resistance and requires more HP.<br /><br />Hydrofoils provide extra "lift", and the faster they boat goes the more lift they provide. The problem here is that once the boat is on plane the "increasing lift" is not required. The bow is pushed down as the boat rotates on it's axis when the stern is lifted. The common solution is the trim the motor out which uses the prop to raise the bow (the prop is trying to offset the lift of the hydrofoil). This runs the prop through the water at an angle which reduces the efficiency. The common result is that the boat runs slower at the top end. The popular school of thought is that this is because of the "drag" created by the foil. Unless the boat is an 80 MPH boat, it is not "drag" it is the two devices working against each other (hydrofoil and prop). The other issue is port to starboard balance with "V" bottom boats. The Hydrofoils lift from the center of the boat and create a teeter totter effect. <br /><br />All adjustable trim tabs provide the boat with a section of the hull that can be manipulated to optimize the hull for the conditions that occur when they occur. Smart Tabs do this automatically and for boats 22' and under simply screw on to the back without the need for electrical or hydraulic hook ups.<br /><br />The name of the game is make the hull as efficient as it can be (ie: with trim tabs), then choose the correct Prop for propulsion.
