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New transmission noise while sailing in neutral

Shawn Brooks

Shawn Brooks

Member II
I've been sailing with the transmission in neutral and never heard this noise before. Has me a little worried. Transmission works fine when under power. Sailing with it in reverse locks the prop as you'd expect. I can turn the shaft with my hand and can feel some irregularity when the shaft is at a particular angle in it's rotation. Very subtle, but it's there.

Video is worth a thousand words: https://www.youtube.com/shorts/i-RUTXQocwc

Any ideas?
 
Navman

Navman

Member III
What kind of prop do you have? My 2 blade Martek prop sometimes makes noise when in neutral with the engine off. I simply put the transmission in reverse then back into neutral all with the engine off and the noise stops.
 
Loren Beach

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
That noisy clicking does not sound right to me. No guess as to what it might be, tho. Hmmmmmm......
 
JSM

JSM

Member III
I still have the original paper work that came with my old Hurth HBW50. There was a tag that hung on the trans stating that it should be locked in reverse while sailing to prevent unnecessary wear. Have you tried changing the fluid. I had problems with mine slipping and found that changing the ATF helped (for awhile).
 
David Grimm

David Grimm

E38-200
Check all your engine mount adjusters. I had one nut backing down causing a misalignment. It was making noise at the cutless! Good as new now.
 
Dave G.

Dave G.

1984 E30+ Ludington, MI
I presume you checked all the coupler bolts ? It almost sounds like one is a little loose and nicking one of the transmission bolts.
 
southofvictor

southofvictor

Member III
Blogs Author
Dave G. said:
I presume you checked all the coupler bolts ? It almost sounds like one is a little loose and nicking one of the transmission bolts.
Click to expand...
Agreed, it sounds like something tied to one spot in the rotation. There’s a flash in the video that’s probably light reflecting off something in the coupling but the timing of it coincides with the sound.
 
LameBMX

LameBMX

Member II
JSM said:
I still have the original paper work that came with my old Hurth HBW50. There was a tag that hung on the trans stating that it should be locked in reverse while sailing to prevent unnecessary wear. Have you tried changing the fluid. I had problems with mine slipping and found that changing the ATF helped (for awhile).
Click to expand...

Not to sidetrack from the real thread, but how much wear are they talking about? being newish to sailing in general (and singlehanded at that), ive made a habit to prep the engine to start right after powering down. So I'm generally sailing with the transmission in neutral. Would like to know both sides of the compromise. (note up north, so glow plug heat time is normally necessary)
 
David Grimm

David Grimm

E38-200
LameBMX said:
Not to sidetrack from the real thread, but how much wear are they talking about? being newish to sailing in general (and singlehanded at that), ive made a habit to prep the engine to start right after powering down. So I'm generally sailing with the transmission in neutral. Would like to know both sides of the compromise. (note up north, so glow plug heat time is normally necessary)
Click to expand...
I just sailed for 6 days straight, Goldenstate just sailed for 3 weeks straight, why would you want to have the prop shaft spinning wearing out the dripless/stuffing box or transmission output seal and bearing for all that unnecessary time. The transmission is to be in reverse position while sailing as per the manufacturer.
 
Dave G.

Dave G.

1984 E30+ Ludington, MI
According to info in the manual reverse or neutral is fine with a Hurth tranny. Under sail I doubt the prop spins more than a 100 rpm unless surfing downwind and then maybe 200 rpm so not much wear in any case. I sail in neutral but if you put it in gear it should indeed be in reverse per Hurth manual.
 

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David Grimm

David Grimm

E38-200
So in 6 days thats 150rpmx60 min in an hour=9000per hour 9000×24hrs= 216,000. 216,000x6days= 1,296,000 rotations in 6 days.

That output shaft bearing and seal are not easy to change! I'll keep mine in reverse.
 
Loren Beach

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
One thing to consider is that these little transmissions use a small amount (about 8 to 10 oz) of ATF for a splash lubricration scheme. Note how low on your little transmission dip stick that the oil "full mark" is stamped.
When the engine is turning the whole set of gears/shafts, the oil is distributed as engineered. i.e. "splash lubrication."

I have no formal mechanical education, but that's my understanding from a mechanic. So that might be the reason that the transmission maker specifies that the trans should be 'locked' in reverse when sailing with engine off.
 
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LameBMX

LameBMX

Member II
David Grimm said:
I just sailed for 6 days straight, Goldenstate just sailed for 3 weeks straight, why would you want to have the prop shaft spinning wearing out the dripless/stuffing box or transmission output seal and bearing for all that unnecessary time. The transmission is to be in reverse position while sailing as per the manufacturer.
Click to expand...
As a new sailor, mental resource management. when its not an emergency I prepare to have a defined starting action for if there is an emergency. Kind of like I am anal about sorting my head sail sheets out the moment I'm done changing course. If there is a drastic wind shift (out on Erie had the wind instantly shift 180 degrees. just had to pop the headsail over to the other side) or something, sorting lines is something I do not have to deal with to handle the situation at hand. As more years and hours at the helm tick by, I will worry less about these items. The original question was more along the lines of how bad is the wear going to be? Should I force recreating a habit with an additional step, which does not work with glow plug timing as I already smashed the crap out of my finger between the shift lever and autopilot trying that.
 
Christian Williams

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
prep the engine to start right after powering down.

Not sure what the issue is. Generally a diesel doesn't need glow plug at all when restarted after running. Putting the transmission in reverse while sailing just means returning the shift to neutral before starting--a check you do anyhow, so as not to start in gear.

Although a diesel will start in gear about as easily as in neutral, with no particular ill effect except the surprise.

Most of us, I think, sail in reverse gear so the prop is still. Tests (this from memory) have shown that drag is less if the prop is freewheeling, but the effect must be relatively small.

Yes, I have a permanently squashed finger from glow plug pressure applied while standing on my head. And I have to push two buttons at once to start the engine. Such pain is a matter of personal taste, as the glow and start buttons can be easily rewired to be independent.
 
David Grimm

David Grimm

E38-200
While holding the glow plug button with your starbord hand, reach over with your port hand and flick it into neutral. If you forget... no worries it will still start in reverse... ask me how I know. lol
 
LameBMX

LameBMX

Member II
David Grimm said:
While holding the glow plug button with your starbord hand, reach over with your port hand and flick it into neutral. If you forget... no worries it will still start in reverse... ask me how I know. lol
Click to expand...
That is the exact procedure I used to smash my finger to the point of swear words between the lever and the autopilot wheel. I may have to give the start in reverse a try after a long day when the battery is pretty low. I've already had to dart below to use the other battery to start the motor :/

But on the bright side, normally reverse and slowing is exactly what I want in those situations.
 
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