Friends,

I seek and I need a help with understanding, where is truth.

Several years ago I start to fit a trim tabs without gap (space) between tab's plate and hull's bottom. So, not a far away I find a photos with real big distance between a tab's plate and hull.
Some guys do this set up like in history, and some guys do this like new.
Where is true?
I feel, the space method is better, but I can't feel it perfectly... on my boat.

Please show me your ideas.

lower photos from MGB, for comments.

Photo with space.

The space = 0

This is my personal opinion on this: I think as long as they are not mounted LOWER than the hull's bottom it is ok. You do not want them dragging in the water. Some manufacturers' recommended settings will vary between 1/8" and 0". Personally I think 1/16" is just right. Allows the tabs to be effective as an extension of the hull and assures they are not dragging in the water when set to 0.

Personally, opt for a small gap.

Reason is less drag along the lines of WHY when a ride surface has a STEP, it allows air to get under the surface further freeing it up.

You still get the down force of the tab reacting against the water, but have not introduced much drag in doing so.

JMO,
Scott

Many thanks!
Colleagues,

you are really help me to reduce my one horror.

I have a some ideas about rear side of each hull, so, each hull is have a unicum shape on the transom area, such grooves, wedges (?), and trim plates must no be change a thin hydrodynamic quality of hull.

Marc, I like your sentence ... not mounted LOWER than the hull ...

Personally i dont use trim tabs anymore i prefer to trim the drive and the rudder to alter the boats ride attitude and handling.
Mart