Blackjack 42 trim tabs

[Marley-Buster]

Has anyone experienced a loss of speed with RCBB trim tabs on the Blackjack 42?

[properchopper]

I'll take a crack at an answer based on some personal trials

My H&M Drifter S is a much smaller cat hull but superbly designed to air out nicely. During NAMBA SAW time trials I was attempting to squeeze out just a bit more top end and adjusted the ride attitude to be just on the verge of blowing over. I could break my existing record downwind but upwind I was blowing over (you need a 2-way average for a record). I did try small trim tabs and yes the speed dropped ; I surmised that the tabs kept the hull from airing out enough to reduce the wetted area and added more real estate in the water for more drag so I ditched them. I might have adjusted them to serve only as "wheelie bars" but didn't. Just my experience - others may have different views

Drifter nicely aired out :

drifter aired out 10.jpg

[Marley-Buster]

I appreciate your insight. I am machining the tabs down from 60x50 to 50x40. Will let you know how it works out.