Advice: Rudder Setback in Relation to Prop

[rickwess]

Now that cottage season is over, it's time to do some serious planning for the winter builds.

My priority will me my 54" Dumas Scarab so these questions are specifically related to that. I don't recall where I read/heard it but I thought the ideal was to have the prop centered with the blade of the rudder. I've researched the large mono builds here and there doesn't seem to be a consistent approach to the setback relationship between the rudder and prop.

So I guess the basic question is, does the the rudder setback matter.....at least from a prop location perspective? If it does matter, then the rudder setback will be dictated by the length of the strut or stinger. If it doesn't matter, what would the ideal setback be for a 54" mono?

Thanks.

[srislash]

On my little Pursuit Rick, I have it set back behind the prop and it does seem to get the transom hopping occasionally. I think my last vid there it does it a couple times. Was going to shorten the standoff but... Time.

[rickwess]

It makes sense to keep the rudder out of the prop wash. Not only for stability, but also to keep the aerated water away from the cooling pickup holes. Maybe it's more critical in the smaller/lighter boats (stability). I just don't have the experience to say one way or the other.

[srislash]

My R-42 is set up to experiment with these things but it is a cat, and not wet yet. Why not make the mono this way. I have a few different rudder standoffs here if you want to play with lengths.

[rickwess]

Brilliant minds think alike.......or is it fools seldom differ??? I was already thinking of getting two extra setback arms from Steve when I order the rudder. I figure 4", 5" and 6" is what I'll need on the large boat. Might get the 2 3/8" just to complete the set for testing purposes.

[Fluid]

The large boats the gas racers run use varying setback. Some use 2" - some use 6" on the same brand hull. I know I tried several different setbacks on my StrikerCat but saw no difference.

I believe in many cases it is simply preference. I remember several gas monos where if the guy who won the Nationals used 6" of setback on his PluperMono then everyone who owned one used that setback. If Another guy won the Nats the next year with 2" of setback, then everybody changed. What matters is what works on your hull, and trying different standoff arms makes a lot of sense.


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[rickwess]

I believe in many cases it is simply preference. I remember several gas monos where if the guy who won the Nationals used 6" of setback on his PluperMono then everyone who owned one used that setback. If Another guy won the Nats the next year with 2" of setback, then everybody changed.
That's pretty funny.

[rickwess]

I believe in many cases it is simply preference. I remember several gas monos where if the guy who won the Nationals used 6" of setback on his PluperMono then everyone who owned one used that setback. If Another guy won the Nats the next year with 2" of setback, then everybody changed.
That's pretty funny.