Hydrofoil on Johnson 112 SPL

[crabby13]

Johnson 112 on Wellcraft 19.5' with a substantial porpoising issue.

Anyone have and experience with the Stingray hydrofoil configurations and/or the SE models?

Hydrofoil vs. trim tab opinions also welcome

Thanks!

 

[Chinewalker]

I'd spend some time and figure out why its porpoising. Foils are often band-aids, at best, masking actual handling issues. Does your motor have power trim? Does adjusting trim angle have any effect on the porpoising? Is the boat properly loaded for best balance? Is the motor able to reach it's optimum RPM (5500-6000 RPM at wide open with light load)? Is the hull straight and true? Sighting down the keel will give you an indication of whether the hull has a hook or rocker in it.

 

[crabby13]

Chinewalker - thanks!

I do have a power trim and am unable to trim out the porpoising. The hull is straight and clean. I believe the motor reaches max RPM. Porpoising will occur on glass water from 2/3 throttle to full.

I did have my son relocate to the bow pulpit the other day and it did lessen the effects but that is not a practical solution as the tradoff was that he got pounded. Chesapeake in the afternoons get pretty bumpy with 15 knots of wind.

I do believe that the craft with the 112 and dual marine batteries is a little ass-heavy. I keep the anchor and 2 x 35# plate weights in the forward storage to offset the weight difference. I often walk around toward the bow during acceleration to get her up on plane quicker.

Thanks again