Whilest out on the lake this weekend, motoring up to set anchor on lake Grapevine here in Texas, I suddenly heard a loud "whomping" vibration (in forward or reverse), then I suddenly lost all power. Engine would rev in either direction, but no prop turning. To keep the story short, I ended up below looking at the shaft-transmission coupling plates sitting about an inch apart, with four bolts, nuts, and lock-washers lying around in the access bay. The transmission and the shaft had *completely* decoupled while under way! There was no outward sign that I can remember that these bolts were loosening, and the bolts weren't stripped (thank goodness - it was a simple matter with a pair of pliers and a crescent wrench to put it all back together and torque the bolts tight enough to feel good about motoring back in that evening). I've now got both plates firmly pressed together and the bolts torqued "hand tight," meaning as tight as I'm willing to pull without fear of stripping the nuts. The history: I took delivery of this 1999 pre-owned Hunter 310 from a dealer, that had taken it in on trade. Part of the deal was to move the boat from another lake in Texas, and to repaint the bottom. They did all of this without any complaints, and seemingly did a good job. However, I am wondering if there is some typical practice involved in repainting bottoms, moving boats, etc. that would involve decoupling the tranny. If so, then I want them to be aware that whoever re-assembled the coupling it did it very poorly. Otherwise, I can only conclude that the bolts had vibrated loose over time. I didn't notice this when we were doing the survey, and neither did the surveyor; it seems like it would have been obvious to spot separation between the coupling plates. So I'm guessing that the bolts were loose, but had not worked loose. We've probably put 3-4 hours on the engine under power since we took delivery. There were 76 hours on the engine when we acquired the boat. If anyone has any ideas about how this sort of thing could have occurred, I'm all ears. Should re-tourquing the transmission coupling bolts be a regular maintenence item? Also, mabye I'm just paranoid, but I seem to notice vibration while under way a little more than I did before. Can't really tell. Could my experience have put the shaft out of alignment? Thanks for all the support. This forum is a great place to ask questions! Best regards, Larry Baker c/v "Flat Broke" Grapevine, TX
- Status
Recap
Recap of symptomology so far: - slightly overworn cutlass bearing for age (as assessed by the surveyor); - (assumption) vibration caused transmission-shaft coupling bolts to vibrate loose; - slight but noticiable vibration under way at >2000 RPM (f'wd or b'wd), possibly aggravated by decoupling-recoupling of transmission-shaft. Theories: 1) Shaft is misaligned. 2) Shaft is bent.
Recap of symptomology so far: - slightly overworn cutlass bearing for age (as assessed by the surveyor); - (assumption) vibration caused transmission-shaft coupling bolts to vibrate loose; - slight but noticiable vibration under way at >2000 RPM (f'wd or b'wd), possibly aggravated by decoupling-recoupling of transmission-shaft. Theories: 1) Shaft is misaligned. 2) Shaft is bent.
Wire bolt heads
On my 29.5, the bolt heads are square and have a hole through them which allows a wire run through to keep them from ever turning more than about 1/4 turn. If you don't have this type bolt, you should get them. Then, what you described can never happen. Also, you should do a quick visual inspection of your engine before going out or upon return to look for leaks, loose clamps, hoses, etc. A lot of problems like the one you experienced can be spotted and fixed before they fail.
On my 29.5, the bolt heads are square and have a hole through them which allows a wire run through to keep them from ever turning more than about 1/4 turn. If you don't have this type bolt, you should get them. Then, what you described can never happen. Also, you should do a quick visual inspection of your engine before going out or upon return to look for leaks, loose clamps, hoses, etc. A lot of problems like the one you experienced can be spotted and fixed before they fail.
Seems Strange .....................
...... as we have a '99 H130 as well and as Gene B. has mentioned, the bolt heads are square with a small hole in them and SS wire passed through such that the bolts can never come loose on their own. This is the factory installation. If yours are not like this, someone has had their fingers where they ought not and done the dirty deed. Hope this helps. Regards, s/v Island Hunter
...... as we have a '99 H130 as well and as Gene B. has mentioned, the bolt heads are square with a small hole in them and SS wire passed through such that the bolts can never come loose on their own. This is the factory installation. If yours are not like this, someone has had their fingers where they ought not and done the dirty deed. Hope this helps. Regards, s/v Island Hunter
not wire heads - bolts.
The two wire heads you're describing are still wired, and they appear not to have turned. That is not the point at which the shaft decoupled. There are two mushroom-shaped plates, one attached to the shaft (with the two wire bolts you see), the other on the transmission. There are 4 nuts and bolts that hold the two plates together, presumably secured against vibrating loose via lock washers. These four bolts had worked loose, finally allowing the plates to separate to the point where the bolts no longer coupled them. Both plates were, however, securely attached to the transmission and the shaft, respectively. The four bolts weren't damaged significantly, i.e. I could hand-tighten the nuts back on with moderate resistance at one or two points. I conclude from this that there isn't enough torque resistance from the prop/shaft assembly to have damaged the threads on the screws - good luck for me. My wife says that after I repaired the coupling (just bolted the four nuts and bolts back together and tightened them down good), that I'd decreased the vibration that's noticable at about 2000 RPM. That would be consistent with a better coupling. I can't tell. I'm paranoid about it now, so any vibration is noticable to me more than it was. My acting theory is that the engine and the shaft are very slightly out of alignment, which is putting stress on the four bolts that couple them together. Over time, the repeated "impact" stress on the nut/bolt causes them to work apart, even with lock washers in place. (Imagine the two plates pressed together, but not quite aligned, and rotating; that puts repeated stress-release type cycles on each bolt, on each revolution of the shaft). The tolerance, I am told, for plate alignment is 0.004 inches. I'm guessing I'm a couple of .001 inches off, at most, which would be consistent with my additional wear on the cutlass bearing, and higher-than-normal packing gland leakage. I doubt that improving alignment will significantly reduce vibration, but it's worth hoping for. I was also told that about once a month I should go down and test those bolts, and re-torque them as necessary. That makes sense. Even with .004" of variance, there's still some repeated stresses on each bolt, that would, over time, cause them to loosen. I've also discovered that there are specialized kinds of shaft couplers that can alleviate some of the issues with vibration and misalignment. They have some kind of compressed rubber sandwich they put between the plates, that allows the engine (which is going to jump around like diesels do) to flex a little independently from the shaft. That makes sense. I just don't know how to select one. Installing it would be another story. Those two wire heads clearly join the coupling head (the mushroom piece) to the shaft. I am assuming that the parts (parts and coupling plate) are machined closely enough to not require alignment themselves, but it's not an assumption I'm willing to test with my $14 West Marine toolkit at my side. Hence, rather than jump into this, I'm going to go buy a good feeler gague and prove to myself that the shaft is/isn't out of alignment. Then I'm going to find someone that knows how to align shafts, and get them to do it for me (and watch closely so I can do it next time). In the meantime, I have had two separate people note that my packing gland is leaking too much. That I can tighten, as long as I get two big-enough wrenches. Thoughts, opinions, advice - welcome! Larry Baker
The two wire heads you're describing are still wired, and they appear not to have turned. That is not the point at which the shaft decoupled. There are two mushroom-shaped plates, one attached to the shaft (with the two wire bolts you see), the other on the transmission. There are 4 nuts and bolts that hold the two plates together, presumably secured against vibrating loose via lock washers. These four bolts had worked loose, finally allowing the plates to separate to the point where the bolts no longer coupled them. Both plates were, however, securely attached to the transmission and the shaft, respectively. The four bolts weren't damaged significantly, i.e. I could hand-tighten the nuts back on with moderate resistance at one or two points. I conclude from this that there isn't enough torque resistance from the prop/shaft assembly to have damaged the threads on the screws - good luck for me. My wife says that after I repaired the coupling (just bolted the four nuts and bolts back together and tightened them down good), that I'd decreased the vibration that's noticable at about 2000 RPM. That would be consistent with a better coupling. I can't tell. I'm paranoid about it now, so any vibration is noticable to me more than it was. My acting theory is that the engine and the shaft are very slightly out of alignment, which is putting stress on the four bolts that couple them together. Over time, the repeated "impact" stress on the nut/bolt causes them to work apart, even with lock washers in place. (Imagine the two plates pressed together, but not quite aligned, and rotating; that puts repeated stress-release type cycles on each bolt, on each revolution of the shaft). The tolerance, I am told, for plate alignment is 0.004 inches. I'm guessing I'm a couple of .001 inches off, at most, which would be consistent with my additional wear on the cutlass bearing, and higher-than-normal packing gland leakage. I doubt that improving alignment will significantly reduce vibration, but it's worth hoping for. I was also told that about once a month I should go down and test those bolts, and re-torque them as necessary. That makes sense. Even with .004" of variance, there's still some repeated stresses on each bolt, that would, over time, cause them to loosen. I've also discovered that there are specialized kinds of shaft couplers that can alleviate some of the issues with vibration and misalignment. They have some kind of compressed rubber sandwich they put between the plates, that allows the engine (which is going to jump around like diesels do) to flex a little independently from the shaft. That makes sense. I just don't know how to select one. Installing it would be another story. Those two wire heads clearly join the coupling head (the mushroom piece) to the shaft. I am assuming that the parts (parts and coupling plate) are machined closely enough to not require alignment themselves, but it's not an assumption I'm willing to test with my $14 West Marine toolkit at my side. Hence, rather than jump into this, I'm going to go buy a good feeler gague and prove to myself that the shaft is/isn't out of alignment. Then I'm going to find someone that knows how to align shafts, and get them to do it for me (and watch closely so I can do it next time). In the meantime, I have had two separate people note that my packing gland is leaking too much. That I can tighten, as long as I get two big-enough wrenches. Thoughts, opinions, advice - welcome! Larry Baker
People scew up
My guess is the bolts were all finger-tightened and then forgotten. It took 75 hours for all of them to fly off. I have been an auto mechanic for 20 years, when I see a problem like yours (only on a car) I can almost always trace it to a human error. The few times I have screwed up and something fell off I have been able to think about it and remember exactly what happened to cause the mistake. Maybe I got a phone call or somebody asked me to stop and help them at just the wrong time. I would monitor the bolts, but I suspect you will not have any moreproblems. Think about how frequently your mind is 100% on what you are doing. Doctors leave sponges in patients, mechanics leave bolts loose. Justin Meddock 1978 h27 SCREW LOOSE
My guess is the bolts were all finger-tightened and then forgotten. It took 75 hours for all of them to fly off. I have been an auto mechanic for 20 years, when I see a problem like yours (only on a car) I can almost always trace it to a human error. The few times I have screwed up and something fell off I have been able to think about it and remember exactly what happened to cause the mistake. Maybe I got a phone call or somebody asked me to stop and help them at just the wrong time. I would monitor the bolts, but I suspect you will not have any moreproblems. Think about how frequently your mind is 100% on what you are doing. Doctors leave sponges in patients, mechanics leave bolts loose. Justin Meddock 1978 h27 SCREW LOOSE
Almost the same situation
I took delivery of my Hunter 290 at the end of April in Bay Shore, LI and moved it myself to my homeport of HaverStraw NY. The following weekend I was checking out the enging and found 2 of the bolts laying under the engine, and the remaining bolts were all loose. I was just glad they didn't all come loose when I was out in the Ocean in 30 knot winds.
I took delivery of my Hunter 290 at the end of April in Bay Shore, LI and moved it myself to my homeport of HaverStraw NY. The following weekend I was checking out the enging and found 2 of the bolts laying under the engine, and the remaining bolts were all loose. I was just glad they didn't all come loose when I was out in the Ocean in 30 knot winds.
just one survey
Yes, I got a survey - and I was there for it. The surveyor and I inspected the packing gland and transmission coupling together. He noted that the packing gland was dripping too much (drip every 5 seconds or so), but didn't say anything about the transmission. I don't remember looking at it that closely. The survey included an out-of-water inspection; this included an inspection of the cutlass bearing, which the surveyor also noted as being a little more worn than he would have expected in a boat this young. He suggested that I replace it while it was out for its bottom job, but due to my own logistical missteps, I didn't get that done. I don't know how one inspects a cutlass bearing, but I am guessing that it does not require decoupling the transmission. My only theory at this point is that the bolts were loose but not enough to notice visually while we did the inspection; after we put it back into service, my heavy-handed learning experiences (backing up - going forward) probably accellerated the loosening. After there was some separation, they probably worked loose pretty quickly (if you've watched the engine jumping around while it's idling, you can imagine the vibration on a loose coupling). I recently saw an example of how fast something can vibrate loose: I'd just put a new Magma BBQ, and had hand-tightened the handle on the top without using a wrench. The vibration of the engine shook loose the handle within about 2-3 minutes. Though this was a much smaller bolt, it was also not subject to the kind of vibration/stresses that the (loose) coupling bolts experienced. One thing I've learned about this: do regular maintenence checks on these bolts! It's a good opportunity to check the packing gland as well. Two medium-sized crescent wrenches will easily torque down the coupling bolts; if you want to be really serious, get a torque wrench and do it to spec. But be careful. Stripping these bolts would be a major pain. If you're not sure of your own strength, get a torque wrench and look up the spec. In my reading around this event, I have learned that there are two possible "improvements" you can make that can alleviate both of these issues (packing gland and tranny alignment/coupling) issues. There is a drip-less packing gland assembly that can replace the exhaust-tube packing gland assembly that hunter uses from the factory. These cost about $300. You would have to pull the boat out of the water to do the replacement. The value is in having a virtually frictionless, dripless, (presumably) maintenence free assembly. There is also a "self-aligning" transmission coupling that has a compressed rubber sandwich between the coupling plates. The manufacturer claims that it can tolerate as much as 2 degrees of misalignment. It costs between $300-600, not entirely clear from the web page. The value would be in reducing strain on the packing gland and cutlass bearing due to misalignment or vibration. I'm not sure it's worth the trouble or expense of putting these two components in, but if you're facing something like replacing a shaft, it might be worthwhile considering. The benefit would be less maintenence and possibly less vibration. Larry
Yes, I got a survey - and I was there for it. The surveyor and I inspected the packing gland and transmission coupling together. He noted that the packing gland was dripping too much (drip every 5 seconds or so), but didn't say anything about the transmission. I don't remember looking at it that closely. The survey included an out-of-water inspection; this included an inspection of the cutlass bearing, which the surveyor also noted as being a little more worn than he would have expected in a boat this young. He suggested that I replace it while it was out for its bottom job, but due to my own logistical missteps, I didn't get that done. I don't know how one inspects a cutlass bearing, but I am guessing that it does not require decoupling the transmission. My only theory at this point is that the bolts were loose but not enough to notice visually while we did the inspection; after we put it back into service, my heavy-handed learning experiences (backing up - going forward) probably accellerated the loosening. After there was some separation, they probably worked loose pretty quickly (if you've watched the engine jumping around while it's idling, you can imagine the vibration on a loose coupling). I recently saw an example of how fast something can vibrate loose: I'd just put a new Magma BBQ, and had hand-tightened the handle on the top without using a wrench. The vibration of the engine shook loose the handle within about 2-3 minutes. Though this was a much smaller bolt, it was also not subject to the kind of vibration/stresses that the (loose) coupling bolts experienced. One thing I've learned about this: do regular maintenence checks on these bolts! It's a good opportunity to check the packing gland as well. Two medium-sized crescent wrenches will easily torque down the coupling bolts; if you want to be really serious, get a torque wrench and do it to spec. But be careful. Stripping these bolts would be a major pain. If you're not sure of your own strength, get a torque wrench and look up the spec. In my reading around this event, I have learned that there are two possible "improvements" you can make that can alleviate both of these issues (packing gland and tranny alignment/coupling) issues. There is a drip-less packing gland assembly that can replace the exhaust-tube packing gland assembly that hunter uses from the factory. These cost about $300. You would have to pull the boat out of the water to do the replacement. The value is in having a virtually frictionless, dripless, (presumably) maintenence free assembly. There is also a "self-aligning" transmission coupling that has a compressed rubber sandwich between the coupling plates. The manufacturer claims that it can tolerate as much as 2 degrees of misalignment. It costs between $300-600, not entirely clear from the web page. The value would be in reducing strain on the packing gland and cutlass bearing due to misalignment or vibration. I'm not sure it's worth the trouble or expense of putting these two components in, but if you're facing something like replacing a shaft, it might be worthwhile considering. The benefit would be less maintenence and possibly less vibration. Larry
Each day-give a look-Always check bolts/fluids
Simply said. I had this problem too. My first year with my 97 H280, believe it or not in NY harbor, eel grass was clogging my engine cooling water intake. As the engine got hotter the vibration shook the boat and those bolts. My dealer said he had seen this a few times. SOLUTION- first, put some "locktight" on the coupling nuts. second, check em often! Hope this helps. Ed
Simply said. I had this problem too. My first year with my 97 H280, believe it or not in NY harbor, eel grass was clogging my engine cooling water intake. As the engine got hotter the vibration shook the boat and those bolts. My dealer said he had seen this a few times. SOLUTION- first, put some "locktight" on the coupling nuts. second, check em often! Hope this helps. Ed
Safety wire and a little lock-tite!
Baker: This is an unfortunate occurance. I think that you surveyor missed this on the survey. That is water under the bridge at this time. Must be sure that the bolts are secured with the proper torque. I also think that a spot of lock-tite would be a prudent think. If the safety wire was to ever come loose the lock-tite is your second insurance policy. Maybe a little redundant but something like this could be dangerous under the right conditions. As far as the shaft seal is concerned, I think that they are a good investment. Have only heard a couple of negative comments and mostly positive. As far as the coupler, my personal opinion is that if you have some real vibration problem, it may be a good thing but for most of us not necessary. If you think that there is too much vibration, have your motor mounts checked first. If they need to be replaced, only use factory mounts. The after market mounts are too soft and cause other problems.
Baker: This is an unfortunate occurance. I think that you surveyor missed this on the survey. That is water under the bridge at this time. Must be sure that the bolts are secured with the proper torque. I also think that a spot of lock-tite would be a prudent think. If the safety wire was to ever come loose the lock-tite is your second insurance policy. Maybe a little redundant but something like this could be dangerous under the right conditions. As far as the shaft seal is concerned, I think that they are a good investment. Have only heard a couple of negative comments and mostly positive. As far as the coupler, my personal opinion is that if you have some real vibration problem, it may be a good thing but for most of us not necessary. If you think that there is too much vibration, have your motor mounts checked first. If they need to be replaced, only use factory mounts. The after market mounts are too soft and cause other problems.
Same Problem
We purchased a new 320 last year and as we began to "motor off our mooring" we did nothing but drift into other boats and act like a pinball machine in some high winds. Guess, what? Your same problem. Totally separated. Rather frightenting as we were new to boating. We now check everytime we go out and make sure the fenders are close by incase we need to grab onto another boat to stop our floating. Dealer came down to fix and haven't had a problem since. Bob S/V Never Say Never
We purchased a new 320 last year and as we began to "motor off our mooring" we did nothing but drift into other boats and act like a pinball machine in some high winds. Guess, what? Your same problem. Totally separated. Rather frightenting as we were new to boating. We now check everytime we go out and make sure the fenders are close by incase we need to grab onto another boat to stop our floating. Dealer came down to fix and haven't had a problem since. Bob S/V Never Say Never
Another 310
Larry, I have a 1998 310 on Lake Grapevine. I did the shaft alinement last month, also adjusted my packing. I have a packing nut wench if you need to use it. You can contact me at Michael.Bourassa@wcom.com
Larry, I have a 1998 310 on Lake Grapevine. I did the shaft alinement last month, also adjusted my packing. I have a packing nut wench if you need to use it. You can contact me at Michael.Bourassa@wcom.com
Wired
Larry, This seems to be a problem common to new boats after about their first year. Yes, you need to routinely check the bolts. They have a specific torque setting in the manual, but something around 65 to 75 lbs is probably adequate (about what an auto wheel lug nut is supposed to be). There should be a split ring lock washer between the nut and outer flange. After setting the torque, safety wire using stainless steel wire. If you have a pair of safety wiring pliers you probably know all the tricks for wiring. If you don't, try this. Take about 2 feet of wire. Leave about 3-4 inches free to tie off after wiring all the bolts. Put a continuous length of wire around the end of the bolt immediately after the nut. Go in the direction of the threads. Wrap about 3-4 times but be consistent on each bolt. Then back around the standing part and over to the next bolt. Do this to each bolt. Stretch the wire tight with a pair of pliers and tightly wrap the two ends together. Don't overdo it with extra wire or extra wraps. If you wanted to do it correctly you would need special nuts that have holes for the safety wire to go through but the above method will work with the rpms we typically experience. Don't use any wire that is not stainless steel or rated as safety wire. You should find some at most automotive supply stores or certainly with your general aviation mechanic at your airport. This will keep the nuts from working loose and falling off. You should still check periodically and especially during the first few years. Just another minor inconvenience they didn't really you about when you started boating. Good luck, Les s/v Mutual Fun
Larry, This seems to be a problem common to new boats after about their first year. Yes, you need to routinely check the bolts. They have a specific torque setting in the manual, but something around 65 to 75 lbs is probably adequate (about what an auto wheel lug nut is supposed to be). There should be a split ring lock washer between the nut and outer flange. After setting the torque, safety wire using stainless steel wire. If you have a pair of safety wiring pliers you probably know all the tricks for wiring. If you don't, try this. Take about 2 feet of wire. Leave about 3-4 inches free to tie off after wiring all the bolts. Put a continuous length of wire around the end of the bolt immediately after the nut. Go in the direction of the threads. Wrap about 3-4 times but be consistent on each bolt. Then back around the standing part and over to the next bolt. Do this to each bolt. Stretch the wire tight with a pair of pliers and tightly wrap the two ends together. Don't overdo it with extra wire or extra wraps. If you wanted to do it correctly you would need special nuts that have holes for the safety wire to go through but the above method will work with the rpms we typically experience. Don't use any wire that is not stainless steel or rated as safety wire. You should find some at most automotive supply stores or certainly with your general aviation mechanic at your airport. This will keep the nuts from working loose and falling off. You should still check periodically and especially during the first few years. Just another minor inconvenience they didn't really you about when you started boating. Good luck, Les s/v Mutual Fun
Your Boat? Your Fault!
Diesel engines vibrate. Fasteners come loose. If you want to own a boat you'd better know how and what to inspect. And don't go blaming a surveyor for your neglect. His job is to be sure the proper parts are there. He's not a mechanic and won't tighten nuts and bolts! Sounds like a new vibration might be caused by a newly bent shaft. (Did I hear THUMP?) Probable if bronze, less likely if stainless. If you've got a badly worn cutless after 76 hours, the equivalent of one season or so you've got a serious alignment problem. Take care of the cutless, then do a serious alignment. Make sure the shaft runs through the stern tube properly and then align the engine to the coupling flange. Forget lock wire on the coupling bolts. You would need to drill the nuts and it would take longer for you to learn than you have. If you want to make sure they stay tight use nylon locking nuts (known as Nylocks), about .25 each at West Marine. You want stuff right and safe? INSPECT and TIGHTEN. And yes, this includes your rigging, steering gear, anchor line and so on. When was the last time you checked your rigging cotter pins and turn buckles? Or your engine mount bolts?
Diesel engines vibrate. Fasteners come loose. If you want to own a boat you'd better know how and what to inspect. And don't go blaming a surveyor for your neglect. His job is to be sure the proper parts are there. He's not a mechanic and won't tighten nuts and bolts! Sounds like a new vibration might be caused by a newly bent shaft. (Did I hear THUMP?) Probable if bronze, less likely if stainless. If you've got a badly worn cutless after 76 hours, the equivalent of one season or so you've got a serious alignment problem. Take care of the cutless, then do a serious alignment. Make sure the shaft runs through the stern tube properly and then align the engine to the coupling flange. Forget lock wire on the coupling bolts. You would need to drill the nuts and it would take longer for you to learn than you have. If you want to make sure they stay tight use nylon locking nuts (known as Nylocks), about .25 each at West Marine. You want stuff right and safe? INSPECT and TIGHTEN. And yes, this includes your rigging, steering gear, anchor line and so on. When was the last time you checked your rigging cotter pins and turn buckles? Or your engine mount bolts?
No Fault Faults
Per the comment that the surveyor should have checked the bolts, I'm firmly sure that he would NOT have done so, even if I had asked him to. Such an act would have opened him up to a liability lawsuit. It wasn't his boat to work on, and it wasn't my boat for me to give him permission. Surveyors are not mechanics. My surveyor made it very clear that he was not a diesel mechanic, and I wasn't expecting him to be one. No, the comment that it is the responsibility of the boat owner to check and maintain these things is dead-on accurate. The trick is coming up to speed on knowing all the things you have to check, and how often. I've had the boat about 3 weeks; without meaning to invoke the fates, it is, in effect, a "crash course" in boat operations and maintenence (pun NOT intended
. All this being said, I feel extremely lucky to have this forum to air my ignorance and learn from the experts. Thanks, everyone, for your supportive and informative replies. Cheers, Larry Baker
Per the comment that the surveyor should have checked the bolts, I'm firmly sure that he would NOT have done so, even if I had asked him to. Such an act would have opened him up to a liability lawsuit. It wasn't his boat to work on, and it wasn't my boat for me to give him permission. Surveyors are not mechanics. My surveyor made it very clear that he was not a diesel mechanic, and I wasn't expecting him to be one. No, the comment that it is the responsibility of the boat owner to check and maintain these things is dead-on accurate. The trick is coming up to speed on knowing all the things you have to check, and how often. I've had the boat about 3 weeks; without meaning to invoke the fates, it is, in effect, a "crash course" in boat operations and maintenence (pun NOT intended
. All this being said, I feel extremely lucky to have this forum to air my ignorance and learn from the experts. Thanks, everyone, for your supportive and informative replies. Cheers, Larry Bakerhow to check for bent shaft?
Per the comment on my problem being a bent shaft, does anyone know a definitive test for this while in the water? After I tightened down the packing gland, I took her out for about 10 minutes, ran the engine up, and went down below to observe the coupling. It was running smoothly. Admittedly, it's going to look like it runs smoothly at 2500-3000 revs; at lower RPMs, it's difficult to factor out the vibration from the engine. As for the cutlass bearing wear, the surveyor indicated that the wear was not excessive, just "a little more" than he would have expected. From what I've read, this could also be the result of a misaligned shaft, which I can (much more easily) correct while in the water, and while I still have some life in the existing bearing. Thanks in advance! Cheers, Larry
Per the comment on my problem being a bent shaft, does anyone know a definitive test for this while in the water? After I tightened down the packing gland, I took her out for about 10 minutes, ran the engine up, and went down below to observe the coupling. It was running smoothly. Admittedly, it's going to look like it runs smoothly at 2500-3000 revs; at lower RPMs, it's difficult to factor out the vibration from the engine. As for the cutlass bearing wear, the surveyor indicated that the wear was not excessive, just "a little more" than he would have expected. From what I've read, this could also be the result of a misaligned shaft, which I can (much more easily) correct while in the water, and while I still have some life in the existing bearing. Thanks in advance! Cheers, Larry
I believe that you need to pull the shaft!
Larry: I believe that the shaft must be pulled and put on a lathe. If you check the archives I think that someone posted something regarding the tolerances that they shaft is expected to be within (as I have NO idea). My suggestion is to just have this all taken care of when you can have the boat out of the water for more than a week. You can plan on replacing the bearing, putting in your shaft seal (if this is what you are going to do) and have the shaft checked and/or replaced if that is what it takes. I got a price on a shaft and it was about $100/ft installed. You will only pay for one pull/splash if you have everything done at the same time.
Larry: I believe that the shaft must be pulled and put on a lathe. If you check the archives I think that someone posted something regarding the tolerances that they shaft is expected to be within (as I have NO idea). My suggestion is to just have this all taken care of when you can have the boat out of the water for more than a week. You can plan on replacing the bearing, putting in your shaft seal (if this is what you are going to do) and have the shaft checked and/or replaced if that is what it takes. I got a price on a shaft and it was about $100/ft installed. You will only pay for one pull/splash if you have everything done at the same time.
If it runs OK?
If it runs OK for now leave it. It is something that can be left for fall and haul-out time. The shaft is not checked on a lathe because there are no centers cut into the ends of the shaft. Shafts are checked for true on "V" blocks. These can be as sophisticated as precision rollers fixed to steel blocks, to plain steel V-blocks, to hunks of wood with "V"s cut into them. The shaft is supported at the ends on the blocks and an indicator is placed in the center. This can be a dial indicator or a piece of bent wire barely touching the shaft. You turn the shaft slowly by hand and observe runout, either as a number on the face of the dial gage or a change in the space between the shaft and gage wire. My guess is that you'd want .003" (three thousandths of an inch) or less. You should be able to get a good idea of what you have with the shaft in place and the boat in the water. Just turn the shaft by hand and watch closely. You should be able to see any extreme runout this way. More accurate obviously is with the shaft out on the bench. Let us know how this turns out in the fall.
If it runs OK for now leave it. It is something that can be left for fall and haul-out time. The shaft is not checked on a lathe because there are no centers cut into the ends of the shaft. Shafts are checked for true on "V" blocks. These can be as sophisticated as precision rollers fixed to steel blocks, to plain steel V-blocks, to hunks of wood with "V"s cut into them. The shaft is supported at the ends on the blocks and an indicator is placed in the center. This can be a dial indicator or a piece of bent wire barely touching the shaft. You turn the shaft slowly by hand and observe runout, either as a number on the face of the dial gage or a change in the space between the shaft and gage wire. My guess is that you'd want .003" (three thousandths of an inch) or less. You should be able to get a good idea of what you have with the shaft in place and the boat in the water. Just turn the shaft by hand and watch closely. You should be able to see any extreme runout this way. More accurate obviously is with the shaft out on the bench. Let us know how this turns out in the fall.
Checking when aligning
Thanks, Steve. I figured there might be one other way to check for a bent shaft. When I finally get to check the shaft alignment, I should be able to see an out-of-true shaft by seeing the place where the coupling flanges touch rotate when I rotate the shaft. If the touchpoint stays in the same position while I rotate, then the shaft has to be more-or-less true, right? If the touchpoint moves around the flange on the transmission, then that would suggest that the shaft is bent (or that the flange itself is not perpendicular to the shaft). At any rate, until I get a chance to compare my boat's behavior with something similar, e.g. another hunter 310 with the same type of engine, I can't really tell whether I have an unusual amount of vibration or not. Cheers, Larry
Thanks, Steve. I figured there might be one other way to check for a bent shaft. When I finally get to check the shaft alignment, I should be able to see an out-of-true shaft by seeing the place where the coupling flanges touch rotate when I rotate the shaft. If the touchpoint stays in the same position while I rotate, then the shaft has to be more-or-less true, right? If the touchpoint moves around the flange on the transmission, then that would suggest that the shaft is bent (or that the flange itself is not perpendicular to the shaft). At any rate, until I get a chance to compare my boat's behavior with something similar, e.g. another hunter 310 with the same type of engine, I can't really tell whether I have an unusual amount of vibration or not. Cheers, Larry
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