- 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