Can anyone out there give some general guidelines about what types of problems/malfunctions etc produce what kinds of phenomena - types of vibrations, rattles, etc when under load? Like, a worn cutlass bearing sounds like "....."... a bent prop shaft acts like/looks like "....."... a bent prop feels like "......".... Would be of interest & a help to lots of us... thanx!
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Jim Russell
Well
I can't give you much help on a bent prop, but the sound of a worn cutless and a bent shaft are somewhat similar. The main difference is where the noise comes from . . . meaning that if you open the access above your drive shaft, you will probably find the bent shaft hitting the through hull tube and can tell that the sounds come from that contact. Misaligned drive shafts will hit without being bent, however and cause the same sound at the same place. One can also jerk on the drive shaft (while it is stopped <grin>) and make it hit the tube if this is the problem. The cutless is a little different in that jerking may not cause a noise, and the noise would not be obvious when viewing the access to the drive shaft. If you dive, you may be able to determine that the drive is loose in the cutless which then makes the diagnosis obvious. Good Luck Jim
I can't give you much help on a bent prop, but the sound of a worn cutless and a bent shaft are somewhat similar. The main difference is where the noise comes from . . . meaning that if you open the access above your drive shaft, you will probably find the bent shaft hitting the through hull tube and can tell that the sounds come from that contact. Misaligned drive shafts will hit without being bent, however and cause the same sound at the same place. One can also jerk on the drive shaft (while it is stopped <grin>) and make it hit the tube if this is the problem. The cutless is a little different in that jerking may not cause a noise, and the noise would not be obvious when viewing the access to the drive shaft. If you dive, you may be able to determine that the drive is loose in the cutless which then makes the diagnosis obvious. Good Luck Jim
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Kevin
Noise
Hello Ted: Thanks for your letter. As I’m sure all of you would agree a “swish” to you may be a “gurgle” to me. So often when I’m working a “problem child” installation over the phone with a customer, I often focus my attention to the frequency of the “swish” and its reaction to the engines increase or decrease of Rpm’s. If the noise frequency increases as the Rpm’s of the engine increase, one can assume that the shaft, propeller and possibly the shaft bearing are the culprits. If the frequency is isolated to one range of Rpm’s, I begin to focus on mechanical componentry. Items like damper plates, couplings, alignment and even injector problems will cause noise which may only take place a specific Rpm’s and not full ranges. Of coarse when this is all taking place one needs to remember that one failing component may cause other components to sound off creating a multiple sound making it more difficult to isolate the problem child. Not sure if this one helps but maybe it gets you closer to hearing and understanding the noise. Sincerely, Kevin L. Woody
Hello Ted: Thanks for your letter. As I’m sure all of you would agree a “swish” to you may be a “gurgle” to me. So often when I’m working a “problem child” installation over the phone with a customer, I often focus my attention to the frequency of the “swish” and its reaction to the engines increase or decrease of Rpm’s. If the noise frequency increases as the Rpm’s of the engine increase, one can assume that the shaft, propeller and possibly the shaft bearing are the culprits. If the frequency is isolated to one range of Rpm’s, I begin to focus on mechanical componentry. Items like damper plates, couplings, alignment and even injector problems will cause noise which may only take place a specific Rpm’s and not full ranges. Of coarse when this is all taking place one needs to remember that one failing component may cause other components to sound off creating a multiple sound making it more difficult to isolate the problem child. Not sure if this one helps but maybe it gets you closer to hearing and understanding the noise. Sincerely, Kevin L. Woody
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Ted
Update
Thanx for the inputs Gents.... we're gonna haul the boat this week & check out the cutlass bearing, zincs, prop, etc... shaft doesn't seem to be hitting the stern tube... but a slight "wobble" in the shaft is visible, which increases with RPMs.... and I've learned that the cutlass bearing in there is likely the original ('81) vintage.... will I be able to hammer out the old one? will a press be required to get a new one in? Appreciate all your thoughts. Cheers
Thanx for the inputs Gents.... we're gonna haul the boat this week & check out the cutlass bearing, zincs, prop, etc... shaft doesn't seem to be hitting the stern tube... but a slight "wobble" in the shaft is visible, which increases with RPMs.... and I've learned that the cutlass bearing in there is likely the original ('81) vintage.... will I be able to hammer out the old one? will a press be required to get a new one in? Appreciate all your thoughts. Cheers
T
Ted
UPDATE 2
Well, hauled the boat... & observed (1) small amount of barnacle growth on shaft & prop; (2) nearly 1/2 the shaft zinc had corroded & fallen off; and (3) the cutlass bearing was worn enough to allow movement of the shaft in any direction... easy to correct (1) & (2), but (3) is proving more challenging, due to skeg hung rudder... basically have to remove the cutlass bearing with the shaft still in place in the strut... NOT fun... but hopefully (eventually) doable...
Well, hauled the boat... & observed (1) small amount of barnacle growth on shaft & prop; (2) nearly 1/2 the shaft zinc had corroded & fallen off; and (3) the cutlass bearing was worn enough to allow movement of the shaft in any direction... easy to correct (1) & (2), but (3) is proving more challenging, due to skeg hung rudder... basically have to remove the cutlass bearing with the shaft still in place in the strut... NOT fun... but hopefully (eventually) doable...
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Dakota Jim Russell
Removing a Cutless Bearing . . . ????
New ones have allen wrench bolts holding them making the removal much easier. Heard a solution was to find a pipe of slightly smaller diameter and using it to drive it out via hammer. However this assumed the removal of the drive shaft. I would guess that this is what you have in mind. Maybe my response will trigger a more informed reply. Jim
New ones have allen wrench bolts holding them making the removal much easier. Heard a solution was to find a pipe of slightly smaller diameter and using it to drive it out via hammer. However this assumed the removal of the drive shaft. I would guess that this is what you have in mind. Maybe my response will trigger a more informed reply. Jim
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Dakota Jim Russell
Ted: Check April 1999 Sail Issue . . . .
Ted, I checked the HOW archieves and found this note Cutless-Bearing Replacement Submitted by Brian Foster on 11/27 at 08:03PM regarding Hunter 30 You might want to check out the April 1999 issue of Sail. There's an article on bearing replacement on p.38. Might be of general help.
Ted, I checked the HOW archieves and found this note Cutless-Bearing Replacement Submitted by Brian Foster on 11/27 at 08:03PM regarding Hunter 30 You might want to check out the April 1999 issue of Sail. There's an article on bearing replacement on p.38. Might be of general help.
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Ted
Update2
All, THANX for all the inputs, they have been a great help!! We first tried to hammer the cutlass bearing out using the "steel pipe of just the right diameter" approach... this worked well until we had about 50% of the bearing pushed out.. then stopped... then your posts advised me to remove the strut... I had seen the bolts/nuts inside the boat, but the outside was puttied (or something) over & painted, so we were concerned it was actually glassed in... turned out just to be heavy layers of epoxy barrier coat... got the sturt off yesterday & so now replacing the cutlass bearing is very straightforward.... ...but now, prop shaft won't come loose from coupling, so gonna cut it so can replace the stuffing box... should I go dripless or traditional?? The fun continues...
All, THANX for all the inputs, they have been a great help!! We first tried to hammer the cutlass bearing out using the "steel pipe of just the right diameter" approach... this worked well until we had about 50% of the bearing pushed out.. then stopped... then your posts advised me to remove the strut... I had seen the bolts/nuts inside the boat, but the outside was puttied (or something) over & painted, so we were concerned it was actually glassed in... turned out just to be heavy layers of epoxy barrier coat... got the sturt off yesterday & so now replacing the cutlass bearing is very straightforward.... ...but now, prop shaft won't come loose from coupling, so gonna cut it so can replace the stuffing box... should I go dripless or traditional?? The fun continues...
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