Hull Vane. A foil for the transom?

[thinwater]

https://www.proboat.com/2024/01/hull...-PBB-2024-3-14


Benefits are said to include wake reduction, considerable reduction in drag near hull speed, and reduced pitching. Sort of like extending the transom ... but better?



Discuss.

[rslifkin]

The idea of adding some dynamic lift aft does have merit even on boats running below hull speed. On my boat (planing hull powerboat) I've found that deploying a little bit of trim tab is beneficial at slow cruise (~1 kt below hull speed). The tabs on this boat are fairly large, so at slow cruise they'd be extended slightly from the stowed position of just above flush with the bottom, just enough to get them either flush or slightly angled down. Not as much as they'd be deployed for running on plane.

The extra bit of lift isn't enough to noticeably change running angle at low speeds or have any measurable impact on speed or wake (with throttle position kept constant), but it does provide noticeable pitch damping in some sea states and also slows and damps rolling motions slightly (they become a little less snappy, in general the boat's motion in both axes feels a bit heavier and less responsive).