Using a manual jackplate and anti-cavitation plate placement.

I have an old boat/motor combo--- a 1974 Starcraft 14' semi-V with a 1986 Johnson 6hp that we fish in protected waters with. I just bought this boat a couple months ago.


I've been working out the kinks of the motor (there were many), but one issue I've overlooked is that it's a long shaft, and this is a short transom. The anti-cavitation plate sits really low under the boat. I have not been able to get this boat to go any faster than 5.0mph in still water, and I know it won't go much faster than that but I was hoping for something a little closer to 8-10. According to my friends who use 6hp kickers on their sailboats here in Charleston, they are going 7-8mph in a sailboat vastly heavier than my little tin can. You'd think hull speed in my case would be a bit more "flexible" lol.


I picked up a free mini-jacker plate from a very generous friend, and I can basically lift this motor up all I want, but I only get 1 or 2 shots at it (depending on hole placement).


Is it best to have the anti-cavitation plate dead even with the keel, about an inch lower than the keel, or about an inch higher than the keel? Or does this matter at all?

the ideal location, is to have the cavitation plate slightly above the water under full power. when the plate is under water, it acts as a plow, and is actually digging in. i would mount your jack plate to locate the prop as close to below the bottom of the boat. then expect to adjust it upward to clear the cavitation plate out of the water under full power. under no circumstances, should the plate be under water at full throttle.

Crankbait, this sounds like a good plan. I can't easily adjust the height of the jackplate when out on that water so I'll set it to something that seems "about right" and try it out.

This boat is painfully slow right now. I think I have the motor running right now, so hopefully the jackplate will help me reach something better than 5.0mph which is my average stillwater speed. Seems like I should be getting a hull speed somewhere around 8-10mph.