Significant Port helm while under power

[Tigue]

I am in the final stages of purchasing a 2003 Hunter 356. The sail boat has a Yanmar 27 HP motor and a MAX Propeller. When under power the boat wants to turn port at higher RPMs (2,500+). I have to counter with a constant turning nudge to starboard. Is this normal? If not do you have any thoughts as to what would cause this?

[Nicholson58]

Originally Posted by Tigue

I am in the final stages of purchasing a 2003 Hunter 356. The sail boat has a Yanmar 27 HP motor and a MAX Propeller. When under power the boat wants to turn port at higher RPMs (2,500+). I have to counter with a constant turning nudge to starboard. Is this normal? If not do you have any thoughts as to what would cause this?

I can hazard a guess that there is prop-wash on the rudder causing the issue. Is the helm fair while sailing? Have you talked to other Hunter owners? There probably is a Hunter owner's forum.

[Steadman Uhlich]

Originally Posted by Tigue

I am in the final stages of purchasing a 2003 Hunter 356. The sail boat has a Yanmar 27 HP motor and a MAX Propeller. When under power the boat wants to turn port at higher RPMs (2,500+). I have to counter with a constant turning nudge to starboard. Is this normal? If not do you have any thoughts as to what would cause this?

Go read this

https://en.m.wikipedia.org/wiki/Propeller_walk

[Tigue]

I did not notice it while under sail. But honestly I was not paying attention as the wind was shifting constantly and at various velocities. But motoring straight forward it became obvious when throttling at higher speeds. The prop walk may make sense but it seems a little me noticeable then basic prop walk. Just enough that is mildly concerning. It has a "MAX" prop on it which I wonder if that could have a significant influence on this. I will try to find a Hunter blog as well. Thanks for input.

[ozskipper]

It will happen under sail on both tacks. Either lee or weather helm.
Under motor its Prop Walk.

[Teranodon]

I have the same problem on my boat, an Ericson 34. The previous owner struggled with it and never found a solution. Presumably, it is due to a prop shaft that is not aligned with the centerline of the boat. It's annoying, and I tend to use the autopilot when under power. There is no hint of it under sail - the Ericson tracks extremely well. I would certainly not buy a boat that did not behave the same way on both tacks under sail (weather- or lee-helm has nothing to do with this nor, IMHO, does prop walk).

[carstenb]

Originally Posted by Tigue

I am in the final stages of purchasing a 2003 Hunter 356. The sail boat has a Yanmar 27 HP motor and a MAX Propeller. When under power the boat wants to turn port at higher RPMs (2,500+). I have to counter with a constant turning nudge to starboard. Is this normal? If not do you have any thoughts as to what would cause this?

There are various types of Max-props to-blade, 3 blade and even 4 blade. I have a 3 blade and I have to say there are virtually no prop walk issues. Actually sometimes I wish it had a bit more propwalk to make docking in tight spaces a bit easier.

[Reefmagnet]

Prop shaft misalignment will cause significant "pull" in my experience. My boat, when first purchased, noticeably pulled to one side under power. I assumed it was prop walk although it was severe enough to be somewhat tiring to helm after a while. Not too long afterwards I discovered that the (new) engine installer (an alleged professional employed by the PO) had not bothered to tighten up the rear mounts and presumably had not bothered to align the shaft. Replaced the mounts and realigned the shaft and the problem vanished. Not sure how much misalignment was there to begin with, but I was surprised at how much affect it had on the steerage under power.

[GordMay]

Greetings and welcome aboard the CF, Tigue.

[Cadence]

Originally Posted by ozskipper

It will happen under sail on both tacks. Either lee or weather helm.
Under motor its Prop Walk.

Ditto on the prop walk, from the OP's explanation.


Not long ago there was thread on that and the OP did find the answer to his pulling only on motoring. As I recall he wasn't over proped but changing prop design solved it. He might go back and find that to be of interest

[hamburking]

Originally Posted by Reefmagnet

Prop shaft misalignment will cause significant "pull" in my experience. My boat, when first purchased, noticeably pulled to one side under power. I assumed it was prop walk although it was severe enough to be somewhat tiring to helm after a while. Not too long afterwards I discovered that the (new) engine installer (an alleged professional employed by the PO) had not bothered to tighten up the rear mounts and presumably had not bothered to align the shaft. Replaced the mounts and realigned the shaft and the problem vanished. Not sure how much misalignment was there to begin with, but I was surprised at how much affect it had on the steerage under power.

I like the answer above.

IMHO, prop walk should be most noticable at LOW speeds, and especially reverse. The faster you go, the less the effect. In general people rave about maxprop products.

FWIW, I had a Hunter Legend 35.5 with a yanmar 3gmf and it tracked straight and true in forward, reverse, fast and slow.

[AnchorageGuy]

This is a known issue with that Hunter and I doubt there is any fix for it. I use to work for one of the largest Hunter dealers. It's a design flaw. It gets worse the more you throttle up and sometimes you can even feel the rudder "wobble" while under power only. Chuck

[Cadence]

Originally Posted by AnchorageGuy

This is a known issue with that Hunter and I doubt there is any fix for it. I use to work for one of the largest Hunter dealers. It's a design flaw. It gets worse the more you throttle up and sometimes you can even feel the rudder "wobble" while under power only. Chuck

Chuck,

That may be the best info. he will get. Chasing an impossible problem to solve wouldn't be fun.

[AnchorageGuy]

Originally Posted by Cadence

Chuck,

That may be the best info. he will get. Chasing an impossible problem to solve wouldn't be fun.

So true. I have commissioned dozens of these right from the factory. Not an impressive boat. Wait until all the other issues start to surface. Chuck

[AnchorageGuy]

Originally Posted by Tigue

I am in the final stages of purchasing a 2003 Hunter 356. The sail boat has a Yanmar 27 HP motor and a MAX Propeller. When under power the boat wants to turn port at higher RPMs (2,500+). I have to counter with a constant turning nudge to starboard. Is this normal? If not do you have any thoughts as to what would cause this?

The reason it has a maxi-prop is because it does help the problem somewhat. With the regular prop, it will tire you out by the end of the day. Chuck