Rear splash from motor

[CD Maynard]

I have restored a 1964 Lone Star Reliant 18'. I mounted a 115 HP Mariner with a manual jack plate on the transom. The boat really needed a longer shaft engine. I re-drilled the jack plate to lower it the 2.5 inches needed to get the cavitation plate where it should be. The boat handles great but at higher speeds it has splash between the motor and the transom that comes up through the middle if the jack plate. Any ideas as to how to solve the problem. I was thinking that a splash shield of some sort could be bolted on the jack plate to cover the area. I just am not sure how much lift it might give the transom by doing that. The splash well does it's job and it is not taking on any water but I am concerned about the water around the engine itself. It also has a rooster tail from the transducer mounted on the rear of the transom. Originally the transducer was up front and through hull. Maybe that is why it was mounted that way????? Any suggestions would be appreciated.

 

[sschefer]

Re: Rear splash from motor

The offset on the jack plate is the problem. If you take off the jack plate and mount the engine like it's supposed to be the problem will go away. Your lonestar needs a 20" mid with the cav plate (the big one just above the prop) set to 1" above the bottom of the hull at center.

Some hulls just don't do well with offset jack plates. The maximum for that hull would be 5" and sometimes even that's too much.

 

[DuckHunterJon]

Re: Rear splash from motor

Does the motor have another "fin" above the cavitation plate? Is that "fin" in good shape (not broken off)? I had a motor (merc 60) that had that piece snapped off, and the only problem it had was what you are describing. I welded a new on in place and it corrected it. Just a thought.