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Torque steer?

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 PostPosted: October 11th, 2017, 8:06 am   
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Joined: August 20th, 2017, 4:34 pm
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I am experimenting with a 30hp omc with a tiller handle on an 11’ vee bottom. The prop shaft is about 2” below the bottom of the boat. I have a 10.375x18” mercury chopper propeller running 44-45mph right now.
I have to counteract a fair amount of force on the tiller (boat steers to the right). I had a similar problem in FE hydro (49ci) with left hand propellers. The boat would turn into the turn by its self, had to let off the throttle to get out of the turn.

My questions are for t boat drivers with cable steering
Do you have torque steer?
How do you compensate for torque steer?
Does anyone put a tab on the skeg?

Thanks. Matt.

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 PostPosted: October 11th, 2017, 12:21 pm   
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Arltralite wrote:
I have to counteract a fair amount of force on the tiller (boat steers to the right). Matt.

Very common problem with tiller steering. SLT racers know all about it. Steve likely will reply to this thread.
- dampeners
- shock cords
- longer steering arms
- a tightening rod thru the steering tube.
- less diameter props

Cable and pulley steering on a T boat does help. Large props on T 850 boats have more torque and they will pull to the side.


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 PostPosted: October 11th, 2017, 2:08 pm   
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Joined: July 13th, 2012, 6:57 pm
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Location: Little Britain, ON
Of all the props we run on our SLT the Merc Chopper has the least amount of torque steer.
That being said we still run a hydraulic damper attached to the steering link and transom, improves controllability but doesn't lessen the amount of torque steer, you'd have to apply counter-acting force with bungee pulley system to dial out all torque steer.
Todd at High Command Distributing stocks ready to install dampers, bungee stuff available at your local sailing store.

You need to get that Chopper running higher. Any decent prop running 2" below pad with give you high amounts of torque steer. You think that's bad, try a Cleaver... 4 times as much.


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 PostPosted: October 11th, 2017, 7:11 pm   
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I have thought about the dampener and shock cords. But I am looking more to eliminate the problem. I was hoping someone would have experience in shaping the skeg.
I am working on getting the propshaft higher. I am concerned about cooling right now. Just waiting for water pressure and cylinder head temp gauges. I have maxed out my transom extension and shims for now. And the motor looks ridiculous perched that high on the transom so you may see one of my other threads on shortening the midsection and the other tread on the low water pick up. I also need a little more cup in the prop blades before I go any higher.

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 PostPosted: October 11th, 2017, 7:21 pm   
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Location: Lakeport, MI
- cupping the skeg can help, but will not eliminate the problem and may induce cavitation
- in FE (T) we bungied the left wing plate back. It leveled off the torque down the straightaways and would turn automatically when burping the throttle to set the boat in the turns.
in the Thundercat with the tiller, you need both anti-torque and steering stabilizer, like Tomcat mentions. Typically anti-torque mechanism is block and tackle setup with bungie cord instead of rope (see avatar). Steering stabilizing is done with a Mercedes steering damper or a hydraulic steering cylinder with the in/out fed together with a valve. Higher end solutions include Merc Big Tiller power steering https://www.mercurymarine.com/en/us/gau ... ig-tiller/ or Merten Titan Steering System http://www.mertenmarine.com/Steering-Systems . Without, this could be you .. https://i.ytimg.com/vi/ZH6agH43vho/maxresdefault.jpg


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