I read that as for an install on a 40' - 50' boat.

Wow! A total of 15 holes per side. Not a DIY for this boy.

Hole locations or screw locations?

I read it as one hole and then the rest are screws.

I've drilled at least that many holes in my hull. once you've drilled the first one, the rest go easy.

Maybe you can put a screw in without drilling a hole? Perhaps we should just call them "drilling opportunities".

I like that.

I imagine these will be very popular with the off-shore fishing crowd. Sometimes those guys back down on fish at 8 or 10 KTS pushing huge walls of water up the transom. I have always wondered how standard tabs withstood that.

Its a nice no-sharp-edges piece for folks boarding over the stern, too.

That is a definite advantage right there.

What about the fact that they don't increase the running surface, though?

Now you are into what I "think/opinion" rather than the facts as I believe them.

I can see how they would help a boat at speed but how well do they help holeshot?

At what speed during hole shot?

I wish I would have bought these instead of the Smart Tabs.....the issue I have w/tabs in general is how they affect the wake for wakeboarding.....these are ideal for that purpose since they are retractable......and as seabuddy notes, they are "out of the way" for boarding over the stern...

RBT, trim tabs, Smart tabs, and the QL system all assist with holeshot only to the extent that they put you on plane more quickly when accelerating from a dead stop.

Basically they snap the bow down then you have achieved a minimal speed for their braking effect to come into play.

That's all any kind of tab system is: a minimal and location-specific braking system, much like sticking the paddle of a canoe into the water when you are moving.