Rudder depths by hull type?

[FE Wannabe]

Is there any "formula" for determining how deep you should run your rudder below your hull? I am really interested rudder depth for my 32" AM Scorpion Mono and my 24" BBY UL1 Hydro, but would be interested in any "rules of thumb" for any hull type.
Thanks,
Brad

[properchopper]

Hi Brad ! While I have no real empirical formula to offer, Here's some thoughts : The longer the rudder, the more drag which could have a small effect on overall speed as well as affecting pulling to one side on offset rudders. OTOH, I like longer rudders on raceboats because : 1] more rudder is in the water in bouncy racewater, and 2] for offshore courses with left turns a longer rudder will stay in the water deeper when banking left. On my monos I use a Speedmaster .21 nitro rudder cut down @ 5/8 ". As far as the hydro is concerened, give Randy a shout. He'll know the answer to that one.

[Bill-SOCAL]

The number I always keep hearing is about 1.25 inches below the bottom of the prop arc.

[FE Wannabe]

Thanks for the replies guys.

I hope sometime to get back out to Legg Lake when you guys are out there again. Maybe this time I can run some boats with you.

Brad

[Bill-SOCAL]

I plan on being there Sunday, rain or shine. I have two boats to sort out for the the race in Fremont next weekend.

[FE Wannabe]

I will have to see if I can get some boats ready by Sunday. It maybe tough getting approval from the warden on Valentine's Day weekend though!