45 twin pulled very hard to right side

[Steve White]

All my twins run same pipe length, same prop pitch, no shimming of struts either. Most of this has been mentioned by others but my top 5 is as follows in order of importance-

1- is turn fin correctly sharpened, blended and angled?
2- is the rudder blade wide enough front to back and running deep enough?
3- props sized, thinned, sharpened correctly and be matched as a set
4- right front sponson should have more AOA than left typically .5 degree
5- zero toe in on left sponson, 3/16" toe in right sponson

Also as far as the rudder blade trim setting I hold a straight edge along the right side of the blade and adjust linkage until straight edge is parallel with the tub (leave radio trim setting to zero initially). With everything else being set as previously described I'm usually just a few clicks away from final rudder trim. A wedge rudder blade centered is not a realistic "zero" trim as I find the load on the left face of the rudder is lower due to water blowout from the props when rudder is mounted on the right side of tub. And on a side note- what is the afterplane length of the tub? I've seen twin tubs that were too short have horrible issues with tracking straight. Just a thought......

^^^ What he said.

Refer to #2. With any setup, rudder width front to rear and depth needs to be a large enough area to get the job done effectively. When everything else looks to be ok, that's where I always make changes. More rudder, then you can trim the depth in 1/8" increments.

 

[John Finch]

If you have tried all that was said here and still have the issue .....there is a cure so simple but nobody ever believes me when I say it. So here it is once again. Put a 4 inch rudder extension on the rudder bracket with a 1 1/4 inch front to back square rudder and the problem is solved. I never run toe in or turn fin offset and my boats go straight with everything square. Like Don said, with the right side of the rudder parallel to the tub. Leverage!!!!!

 

[Joe Warren]

Turn servo problem or low voltage . The boat tries to turn right because of prop walk. Servo holds it straight.

 

[dr gary turner]

In my limited experience if all of the other items are correct, sponsons square with the tub with maybe a slight toe in, big enough rudder servo and battery, the sponsons are NOT RUNNING WET, same pitched props, 9 out 10 times it is the turn fin

Sharping is critical
If you look at the leading edge of the turn fin and it looks like the leading edge of an airplane, IT WILL PULL THE BOAT TO THE RIGHT

THAT SHAPE CREATS A LOW PRESSURE ON THE OUT SIDE OF THE TF AND THE BOAT IS PUSHED TO THE RIGHT
I use bluing and paint the rudder on the outside of the TF. Scribe a line paralleling the leading edge one inch from the leading edge.

Then sharpen to that line

I just did a TF for my 101 twin and it took me at least 4 maybe 6 hrs to get it correct

Just the ramblings from an old doctor that doesn’t know anything

 

[dr gary turner]

The sharpening goes progressively away from the leading edge at least 1 in

 

[Wasted wages]

I clamp mine in the vise and use a set of progressively finer files....as Doc said, it takes a few hrs to get one right. I've seen people use belt sanders and wheels, but they usually work the tapered part of the fin back to far...

 

[Tom Foley]

I need to work with some of these mentioned aids as I run 5/16 " right sponson toe in and 1/8" left sponson toe out . Dick Tyndall turn fin helped a lot with rudder left trim . Sadly I spend little time trying to improve things and just thrash for the next race . lol my buddies know my MO .

 

[timothy johnson]

Yes Tom I know your MOA, but you do well at most races, may not want to change anything. Maybe Charleston this OCT.

 

[charles siler]

I need to work with some of these mentioned aids as I run 5/16 " right sponson toe in and 1/8" left sponson toe out . Dick Tyndall turn fin helped a lot with rudder left trim . Sadly I spend little time trying to improve things and just thrash for the next race . lol my buddies know my MO .

And has the most wins of any one lol

 

[Tom Foley]

Yes Tom I know your MOA, but you do well at most races, may not want to change anything. Maybe Charleston this OCT.

Definitely planning on Charleston !!

 

[timothy johnson]

Good to hear.

 

[Norm Doerr]

In my limited experience if all of the other items are correct, sponsons square with the tub with maybe a slight toe in, big enough rudder servo and battery, the sponsons are NOT RUNNING WET, same pitched props, 9 out 10 times it is the turn fin

Sharping is critical
If you look at the leading edge of the turn fin and it looks like the leading edge of an airplane, IT WILL PULL THE BOAT TO THE RIGHT

THAT SHAPE CREATS A LOW PRESSURE ON THE OUT SIDE OF THE TF AND THE BOAT IS PUSHED TO THE RIGHT
I use bluing and paint the rudder on the outside of the TF. Scribe a line paralleling the leading edge one inch from the leading edge.

Then sharpen to that line

I just did a TF for my 101 twin and it took me at least 4 maybe 6 hrs to get it correct

Just the ramblings from an old doctor that doesn’t know anything

Good point....hence... taking the turn fin off the boat and run it.

 

[dr gary turner]

Yep the ultimate TF test