N33 pulls to port under power

[sailingdog]

Not to mention, if the engine wasn't properly aligned, the cutless bearing would be getting badly worn...

[deniseO30]

I agree on the alignment. since we replaced the cutless bearing and installed the PSS seal my boat was pulling to the port heavily while under power. I'm planning on getting more help aligning the shaft as soon as weather permits,

[Faster]

With balanced spade rudders it's not unusual to have a significant "pull" one way or the other under power. It is in fact caused by the prop wash, and the way it is acting on the "balancing" tab - ie the area of the rudder ahead of the rudder stock.

The degree of this pull is affected by the balance area and the proximity of the prop to the rudder. It can be quite strong, esp if the rudder is on the verge of being over-balanced.

We discovered this first hand some years ago with my brother's Ranger 28. It had an unbalanced skeg rudder that had extremely heavy weather helm under sail and the boat was a broach machine. During a refit we cut off some of the skeg and added it to the leading edge of the rudder to create some balance forces. Unfortunately we overdid it a bit and, while that resulted in much improved rudder balance under sail, under power the pull on the tiller was excessive (previously there had been none). The balancing area we created was just a few square inches more than what the factory did in later models, but the effect was noticeable.

So this pull on the N33 may be "normal", it would be good to get some input from other actual owners.

[elcap373]

Things are looking up. Another broker (not the seller's) turned me on to a local mechanic who is very knowledgeable. Turns our he also owns a Newport 33. We discussed the issues and are going to meet in the morning for a test spin and inspection. He'll be able to contrast 'normal' to the behavior of his boat.
rwm

[BarryL]

Hello,

My Newport 28 used to pull to one side or another (I can't remember which side) under power. My O'day 35 pulls to port under power. I would not worry about it.

Barry

[celenoglu]

This is most probably to unclean bottom. When a boat is kept in water staying in the same place, one side might catch more organizims than the other. The main reason is the sun. The sun effects growth. If there is something wrong with the propellor, shaft or the rudder the rudder will not be loaded on one side but the boat will travel sideways without any load on the rudder.

If the boat is in the water now it means the bottom is cleaned. Recheck it.

[elcap373]

It shouldn't be growth. It pulled to port both before and after we hauled her out. On the haul out we had the bottom pressure washed.
I'm meeting the mechanic that owns a N33 in the morning. We'll see what he thinks.
Thanks for everyones thoughts. I'll update all after our test in the morning.
rwm

[elcap373]

Well, just came back from a detailed inspection of the engine and boat with a very detail oriented mechanic who also owns a N33! He inspected the engine and noted some minor issues. He listened to the engine at various throttle settings and under load. We took the boat for a test spin. He thought the pull to port was similar to that he experiences with his N33. He noted he normally motors with a throttle setting at around 2100 rpm. We had been motoring with the throttle at around 2400 to 2500 rpm. Since I would emagine that the force against the rudder generated by propwash would increase by some proportion to the square of the velocity - the force was far greater at the higher rpm. So what he saw didn't concern him.

The prop shaft seemed well aligned and turned freely (if it was significantly out of alignment it would have bound in the cutless bearing).

The mechanic also knew the mechanic that did the work prior and spoke well of him. He thought all was well other than some minor issues.

So - I'm going to buy her.

Thanks again for everyone's thoughts.

rwm