Trim Tab Mounting Angle, Parrallel to Hull or Horizontal ??

[Rage]

What are the pros and cons of trim tab mounting angle of the tabs parrallel to the hul versus horizontal assuming no hardware interference problems? i.e. what are the performance advantages on the water one versus the other?

I saw some disscussion here a while back on some racing team(s) running horizontaly mounted trim tabs versus the typical mounting parrallel to the hull. Any merit to this?

[sleeper_dave]

Well, you're looking for lift. If you mount them horizontal, all the force goes into lift, and the tabs aren't fighting each other trying to push the boat to the side.

But when i had new tabs put on last month, it was cheaper to leave them paralell to the hull. Less holes to fill. So that's the way i went, even though i wanted them the other way.

[Rage]

Originally Posted by sleeper_dave

Well, you're looking for lift. If you mount them horizontal, all the force goes into lift, and the tabs aren't fighting each other trying to push the boat to the side.

But when i had new tabs put on last month, it was cheaper to leave them paralell to the hull. Less holes to fill. So that's the way i went, even though i wanted them the other way.

Yes, that's what logic tells me but I'm trying to find out if there is some pitfall that has not occured to me about the horizontal mounting. Also why has the parrallel to the mull mounting been so popular for so long and continues to be what people like Bennet recommend in their installation instructions.

You would think that the tab manufacturers would be the first to recommend a more performance efficient installation.

[Underdog88]

Mine are somewhat in between. They work well. Split the difference and have the best of both worlds

[Larry D]

horizonal makes sense to me however the consenses is if the boat spins out with the tads horizonal it is much more likely to barrel roll ( that is what keep me from mounting them horizonal) but that is on a race boat you shouldn't be pushing a pleasure boat that hard in turns
Larry SVL#51 wild ride

[IRONMAN]

On a 24 deg hull about 17deg to 20 deg would be good. I think that if you are flying and landing a little angle to one side or another you want the tab to give as much lift as possible but if it is completely horizontal it could promote chine walk by landing at a reverse angle. Underdog, I like your Velocity, I looked at that boat in november, very clean. Good luck

[Rage]

Well those are definately some consequences that would not have occured to me. Much appreciated. Any other issues?

How many degrees above the plane of the hull surface would be best for low/zero drag with the tabs full up?

[Larry D]

usually they are mounted 1" above bottom

[Underdog88]

Ironman... thanks. I love it so far.

[Rage]

Originally Posted by Larry D

usually they are mounted 1" above bottom

One inch above the bottom and parrallel to the hull or at an additional angle (? degrees) from the hull / water?