I have a 19.5' Nitro with a Yamaha Vmax 150 TRP on a 6" jackplate. Right now I am on the 3rd to bottom on my engine mouting holes.I still have plenty of water pressure so I was thinking about going up to the last hole but Don't know if that is ok? I thought it might put to much stress on the transom or jackplate? I still have a bit over 1" on the jackplate that I could go up but the adjustment screw is frozen so the jackplate is not an option.<br /><br />Thanks
<br /><br />The idea of a jackplate is to raise the engine and prop as high as possible without exposing the prop or the water intakes to air and without prop ventilation in sharp turns.<br /><br />Your jackplate moves the foot farther away from the transom and gives the water room to rise before it gets to the foot. That means the anti-ventilation plate (usually misnamed the cavitation plate) can be raised anywhere from 3" to 6" higher than level with the bottom of the transom.<br /><br />The best rise ("X" dimension) is found for your particular boat, engine and prop by experimentation.<br /><br />Good luck.