Just wondering if anyone else with a 37C is experiencing a wheel pull to starboard under power. The pull becomes pretty hard when exceeding 2100 RPM's and is annoying during long motoring sessions. My boat had been refitted with a new Perkins M30 when I bought it so I'm not sure if this is a inherent problem with the 37C or just a possible alighnment problem when the new engine was installed. I never really was concerned about it before but as I get older and weaker and I push the boat harder and harder under power it becomes a chore to hold it steady! Good arm excersize though! As I get closer and closer to departing for paradise I realized that many hours behind the wheel would be torture and hard on the auto pilot as well. Anyone delt with this before? Thanks, Tom Hadoulias S/V Lite Chop
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Me Too
Yeh, Tom, me too. I have a 4 cylindar, 40 hp Yanmar with a three bladed, fixed prop. I have an old Autohelm 4000 wheel autopilot which I use about 97% of the time. It's a real strain on the autopilot but it has lasted over 10 years, now. Takes the strain off the ol' arms, though. I think it has something to do with the vortex from the prop and the shape of the hull and rudder.
Yeh, Tom, me too. I have a 4 cylindar, 40 hp Yanmar with a three bladed, fixed prop. I have an old Autohelm 4000 wheel autopilot which I use about 97% of the time. It's a real strain on the autopilot but it has lasted over 10 years, now. Takes the strain off the ol' arms, though. I think it has something to do with the vortex from the prop and the shape of the hull and rudder.
Turns to stbd
I sail an '85 h37c with a 4 cyl yannmar and a two bladed prop and it wants to turn to starboard also under power but I use the auto pilot and Autohelm 5000 98% on the time while under power and it is not a problem. It is actually a big help in moving around in a marina trying to back into a slip. Learn to use it to your advantage.
I sail an '85 h37c with a 4 cyl yannmar and a two bladed prop and it wants to turn to starboard also under power but I use the auto pilot and Autohelm 5000 98% on the time while under power and it is not a problem. It is actually a big help in moving around in a marina trying to back into a slip. Learn to use it to your advantage.
never noticed it.
We've still got the original 3qm30 and a big 3 blade. In 10,000 miles of cruising I never noticed any pull to either side.
We've still got the original 3qm30 and a big 3 blade. In 10,000 miles of cruising I never noticed any pull to either side.
For what it's worth - - - -
My 33 with the orriginal 2GM with 2 bladr prop had the slightest wheel pull to port under power. After switching to a 3GM30 and 3 bladed prop with considerably greater pitch which ended up a wee bit closer to the rudder the pull is much stronger, particularly under strong acceleration. Both got worse after I had the prop repitched an inch steeper, and extending the leading edge of my rudder forward a quarter of an inch didn't help either. If I lay on full fuel from rest the pull and vibration is very strong, but as the hull picks up speed pull and vibration through the wheel decrease, but are always there. My guess is that it is water being thrust against the side of the leading edge of the rudder by the surface of the prop blade. Cure? Probably move the prop as far forward away from the rudder as possible, somehow use less pitch, probably by going to a lesser pitch 3 blade prop.
My 33 with the orriginal 2GM with 2 bladr prop had the slightest wheel pull to port under power. After switching to a 3GM30 and 3 bladed prop with considerably greater pitch which ended up a wee bit closer to the rudder the pull is much stronger, particularly under strong acceleration. Both got worse after I had the prop repitched an inch steeper, and extending the leading edge of my rudder forward a quarter of an inch didn't help either. If I lay on full fuel from rest the pull and vibration is very strong, but as the hull picks up speed pull and vibration through the wheel decrease, but are always there. My guess is that it is water being thrust against the side of the leading edge of the rudder by the surface of the prop blade. Cure? Probably move the prop as far forward away from the rudder as possible, somehow use less pitch, probably by going to a lesser pitch 3 blade prop.
You could install. . . .
a 2QM20 with a two-blade. Then you wouldn't have enough power to feel a pull to starboard. In fact I'll trade you even up.
But if an A4000 autohelm lasted ten years that thing of yours should go forty. Besides, what are first mates for?
a 2QM20 with a two-blade. Then you wouldn't have enough power to feel a pull to starboard. In fact I'll trade you even up.
But if an A4000 autohelm lasted ten years that thing of yours should go forty. Besides, what are first mates for?Thanks Guy's...
I may have to get a bigger wife! Or increase my alternator size to accomodate the juice my hydraulic autopilot will use. Seriously though, in reading the responses I think some boats have an alignment problem with the shaft centerline angle and rudder position where the prop wash isn't centered on the leading edge of the rudder. I say this because Gene is running a three blade prop without the problem and some are getting it with a two blade in the original configuration as installed by Hunter. Then some of those same two and three bladed versions I've talked to don't have it. Alignment seems to be the only possibility as I don't see a generic problem to a specific prop configuration. I'll follow up with this if I can figure it out and I thank all for your suggestions. I welcome more thought's if there are some as well. Tom Hadoulias S/V Lite Chop
I may have to get a bigger wife! Or increase my alternator size to accomodate the juice my hydraulic autopilot will use. Seriously though, in reading the responses I think some boats have an alignment problem with the shaft centerline angle and rudder position where the prop wash isn't centered on the leading edge of the rudder. I say this because Gene is running a three blade prop without the problem and some are getting it with a two blade in the original configuration as installed by Hunter. Then some of those same two and three bladed versions I've talked to don't have it. Alignment seems to be the only possibility as I don't see a generic problem to a specific prop configuration. I'll follow up with this if I can figure it out and I thank all for your suggestions. I welcome more thought's if there are some as well. Tom Hadoulias S/V Lite Chop
I'm with Gene
My 3GM and 2 blade prop give me no helm. I was thinking perhaps it may be longitudinal misalingment, but the comments about proximity to the rudder sound plausible, too. I'm planning on adding inches to the forward edge of the rudder this winter for better reponse off the wind. Maybe I'll get some motor helm. That will be something to report back on next spring. Ah, winter....
My 3GM and 2 blade prop give me no helm. I was thinking perhaps it may be longitudinal misalingment, but the comments about proximity to the rudder sound plausible, too. I'm planning on adding inches to the forward edge of the rudder this winter for better reponse off the wind. Maybe I'll get some motor helm. That will be something to report back on next spring. Ah, winter....
For what its worth...
I have a 3QM 30 with a two blade. I haven't experienced what I would call pull on the rudder, but once the helm is swung port or stbd from the centre line while under power, it wants to go all the way to the stops. I attribute this to the "semi-balanced" design of the rudder - all that surface area forward of the rudder post really catches the prop wash.
I have a 3QM 30 with a two blade. I haven't experienced what I would call pull on the rudder, but once the helm is swung port or stbd from the centre line while under power, it wants to go all the way to the stops. I attribute this to the "semi-balanced" design of the rudder - all that surface area forward of the rudder post really catches the prop wash.
Pull under power
I have a 33 2QM16 with a new 3 blader and a fresh shaft and strut alignment. I'll get "prop walk" when I first start to spin the shaft but at speed it handles relatively well. I would check your shaft alignment relative to the centerline and rudder. Take a look at your bearing wear at the cutlass bearing and see if it's off center. Any play in the strut or shaft? Look at where the shaft exits the stern tube and see if it is relatively centered. That much force just doesn't sound right. I found that an extreme amount of vibration under a hard rudder was caused by wobble at the strut causing turbulance. Our shaftline was considerable out of alignment and when fixed it was smooth as silk, except I have a tad bit too much prop for our diesel. I realize you've got another 4 foot of boat but alas. Garry
I have a 33 2QM16 with a new 3 blader and a fresh shaft and strut alignment. I'll get "prop walk" when I first start to spin the shaft but at speed it handles relatively well. I would check your shaft alignment relative to the centerline and rudder. Take a look at your bearing wear at the cutlass bearing and see if it's off center. Any play in the strut or shaft? Look at where the shaft exits the stern tube and see if it is relatively centered. That much force just doesn't sound right. I found that an extreme amount of vibration under a hard rudder was caused by wobble at the strut causing turbulance. Our shaftline was considerable out of alignment and when fixed it was smooth as silk, except I have a tad bit too much prop for our diesel. I realize you've got another 4 foot of boat but alas. Garry
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