Sport 40 Rudder length

[SeanKewley]

I have a Whiplash Sport 40 and I was wondering what rudder length is a good starting point. I seem to remember reading that 1.5" below the prop arc is the "ideal" length, but I also realize that this is a tuning point as well, so it will vary setup to setup.

1.5" below the prop arc seems a bit long. Any input on a good starting point would be appreciated.

Some info on my setup...

CMB 45HR

Prop = x450/3 blade

Strut depth measured from bottom of transom = 7/8"

Thanks!

 

[TimothyJones]

I'm sure your thinking it will go faster with it shorter? I personal opinion Is leave it alone it sounds right. B)

I really don't think it will make a difference you will see. If it comes out of the water you might want that extra 1/2".

But I'm interested of what determines or what formula people use or is there one!!

Tim

I have a Whiplash Sport 40 and I was wondering what rudder length is a good starting point. I seem to remember reading that 1.5" below the prop arc is the "ideal" length, but I also realize that this is a tuning point as well, so it will vary setup to setup.

1.5" below the prop arc seems a bit long. Any input on a good starting point would be appreciated.

Some info on my setup...

CMB 45HR

Prop = x450/3 blade

Strut depth measured from bottom of transom = 7/8"

Thanks!

 

[SayMikey]

I'm sure your thinking it will go faster with it shorter? I personal opinion Is leave it alone it sounds right. B)

I really don't think it will make a difference you will see. If it comes out of the water you might want that extra 1/2".

But I'm interested of what determines or what formula people use or is there one!!

Tim

I have a Whiplash Sport 40 and I was wondering what rudder length is a good starting point. I seem to remember reading that 1.5" below the prop arc is the "ideal" length, but I also realize that this is a tuning point as well, so it will vary setup to setup.

1.5" below the prop arc seems a bit long. Any input on a good starting point would be appreciated.

Some info on my setup...

CMB 45HR

Prop = x450/3 blade

Strut depth measured from bottom of transom = 7/8"

Thanks!

I run a Speedmaster 20 rudder and cut about an inch off of it. Not square cut unless you want lift. I slightly back cut say 1/8 from leading edge back the rear being shorter

 

[glenng]

I have a Whiplash Sport 40 and I was wondering what rudder length is a good starting point. I seem to remember reading that 1.5" below the prop arc is the "ideal" length, but I also realize that this is a tuning point as well, so it will vary setup to setup.

1.5" below the prop arc seems a bit long. Any input on a good starting point would be appreciated.

Some info on my setup...

CMB 45HR

Prop = x450/3 blade

Strut depth measured from bottom of transom = 7/8"

Thanks!

Sean, I seem to remember 2" below the CENTERLINE of the shaft. I could be wrong- I just leave the blades full length till I Find out how well the boat turns. Remember spt. 40's are prop riders and @ 2" below centerline will leave 2" of rudder in the water.

Glenn

 

[SeanKewley]

Thanks for the input guys.

 

[Bill Gibson]

Sean, just remember the longer the rudder the more drag there is on the boat, which not only affects the top speed of the boat, but can also affect how the boat corners.......I have a 20 Whip that with the help of a very experienced racer we shortened the rudder in VERY small increments, until the boat was right, and it made a HUGE difference in the speed and turning of the boat...perhaps you could contact Brian or Bob Blazer as im sure they could get you well within the ballpark with that boat!

 

[M@MRacing]

I run a Seaducer 20 mono rudder works great cut back just like Mikes