somebody along the way installed a thru hull with a large bronze scoop/grate on my boat, no idea why, question is how much speed does that drag cost ? really considering going back thru std bravo drive ?? thanks Rob

It can be substantial.
Steve

Agreed, but depends on how fast you're going. At 70 MPH in your boat for instance, it's probably less than 1 MPH. At over 100 MPH, it gets more significant in a hurry.

When I bought my Corsa it was a successful A class boat (Hog's Breath). We bolted a HP 500 in it winter of 1997 it went 73.4 MPH. We removed a pretty well done transom pickup and netted a 1.7 MPH increase. In the end the boat set the Kilo at 81.034 in Sarasota.
Sweat the little stuff!
Steve

The water going through the drive also helps cool the gear oil.
Steve