2015 Cobia 237 rolls side to side

[ChrisH]

I just bought a 2015 Cobia 237 CC with dual Yamaha 115s. My first day off shore yesterday was a little dodgy. There was a slight 1 foot swell. At speeds of about 20 to 25, it ran fine. As soon as I went to 30 or over, the boat would roll uncontrollably to one side. I was messing with Trim tabs  to try correct it but would eventually have to back off the speed as it just got worse or it would roll to the other side. The primary reason for this boat was the deep V and stability in rougher seas but it felt very unstable at low speeds and the rolling made it worse at higher speeds. This can't be normal and i must be doing something wrong. Any pointers?

[Moderator]

Check and confirm your tabs are working correctly.

[ChrisH]

Yes, trim tabs are all working correctly. 

[jh141]

Make sure the Trim and Tilt is working correctly on Both motors. What you describe sound like a buddies 26 Century was doing when one of his F150s would not trim all the way down.  

[Moderator]

Are the engines counter-rotating ? Because if they both turn in the same direction the torque can drive the bow down to one side.  There are zinc ‘rudders’ behind the props that help with this torque.  Take a look and make sure they are set correctly.  That 237 is a safe and solid hull.  Something is not set up correctly.. A trip to a good Yamaha mechanic, or a competent outboard rigger would be the next step.  Check the props and see what they are.  Maybe too much stern lift..

MM

[slyshon]

Trim the engines higher when running at higher speeds.  Without enough trim at higher speeds you are pushing the bow down causing it to "roll".  Trimming will get the bow higher. 

Skip

 

[fin-addict]

Also check to make sure both props are the same size and condition. 

[MuddyBottomBluz]

And tabs in the up position when adjusting trim of the engines in order to get the bow up.