Boat darting right randomly
 

Hey guys just looking for some input. I have a 90 Wellcraft Nova 26 ST with twin 350 mags and alpha ones. Had her out yesterday in waves 2 foot or less and it would randomly dart to the right hard!! The starboard trim tabe is slightly tweaked and the starboard skag is broken a little off the bottom from the previous owner. although the tab is slightly tweaked it seems like the boat was handling better with the tabs down and drives trimed up. As soon as i pull tabs the boat would randomly shoot hard right. Did this too me cruising at 3500-4000rpm and also at WOT. The pull was just much more noticable at WOT. Any input would be helpful, thanks in advance!

Did the boat turn but the wheel did not, or did the steering wheel turn as well? Have you made sure that there is no play between the drives? Do you have a tie bar?

Sounds like sloppy upper gimbal swivel pins. Also, being twin Alpha's, I'll bet they are both right hand rotation, this will cause weird handling issues when the waves kick up.

I was thinking the gimbal as well.......pull the boat and see if there is any side to side play in the drives. If it moves much you found the problem. It will get worse and eventually stay nearly 90 degrees hard right....with you potentially in the water watching the boat come around in a circle towards you.

Lots of twin engine Alpha boats used RH rotation drives on both sides. Do you have counter rotating drives????

They are in fact counter rotating. Pin in the steering makes sense because anchored in rollers i noticed a little bit of water coming from that area of the transom plate when the stern dropped into the trough. Also i do have a tie bar what is your guys best suggestion for fine tuning its length? i measured from like the front of each lower and the back if that makes sense. Also it doesnt feel like the wheel is getting pulled with the boat when it cuts.

Thanks a ton for the speedy responses!!

I would set them up even center of the front of the drives to center of the back of the prop shaft. Maybe a little in. That wont make the boat go out of control like you are talking about I don't think unless it is WAY out of allignment.

You probably have a internal tie bar as well. Take the tie bar off to check the side to side movement.

It does have an internal tie bar too is it only runs one cylinder for power steering if that is what you are referring too...the way I measured they were set in half an inch so I was pretty happy with that.

Re-read this post. I wouldn't drive the boat until its fixed