Pulled the boat (2004 H36) for bottom paint. Found worn Cutlass bearing. This is the second time I have replaced the Cutlass in 3 years. Boatyard says excessive wear is due to misalignment of the strut with the shaft resulting in excess pressure on the bottom of the cutless bearing. (See photo). We have aligned the motor but this does not seem to change the shaft alignment in the strut. Boatyard has recommended realigning the strut which involves removing the strut and adding shim and cant. If anyone else has had experience with this problem or has other suggestions I would love to hear. Thanks, Brian Matthews
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other options
How well do you trust this yard? The reason I ask is that realigning the engine, if done properly, should fix this. Alternatively, if there is sufficient room, install a flexible shaft coupling yourself instead of trying to remount the strut.
How well do you trust this yard? The reason I ask is that realigning the engine, if done properly, should fix this. Alternatively, if there is sufficient room, install a flexible shaft coupling yourself instead of trying to remount the strut.
The typical...
..cutlass bearing lasts 10 to 15 years. The major reason for premature failure is misalignment. A preliminary alignment can can be done with the boat out of water BUT you MUST do a final alignment after the boat has been in water for at least two weeks. The hull will change shape after sitting in water and will require realignment. This is most definitely your problem.
..cutlass bearing lasts 10 to 15 years. The major reason for premature failure is misalignment. A preliminary alignment can can be done with the boat out of water BUT you MUST do a final alignment after the boat has been in water for at least two weeks. The hull will change shape after sitting in water and will require realignment. This is most definitely your problem.
Yes, Probably Needs A Strut Alignment...
If the strut isn't aligned correctly, you can waste your time with the engine. I had to have mine re-done after I wrapped a mooring line which tweaked it just enough. It isn't a big deal to do by the way. I think they charged me 2.5 hours, altho that was with the shaft uncoupled anyway for a bellows replacement. Rick D.
If the strut isn't aligned correctly, you can waste your time with the engine. I had to have mine re-done after I wrapped a mooring line which tweaked it just enough. It isn't a big deal to do by the way. I think they charged me 2.5 hours, altho that was with the shaft uncoupled anyway for a bellows replacement. Rick D.
shaft alignment
The alignment should fix this if and only if the shaft is not riding on the tube thru the hull. This could be a big problem if its wearing thur the tube. so I think i would want to pull the shaft and look at the area where the shaft runs thru the hull while your at it. The previous post is correct in that you must align the shaft after it sets in the water for a while. but if the shaft is wearing like the picture then it could be the wrong alignment or the shaft if binding between the tube and the strut, or the shaft is bent, or the cutlass they put in was not the correct size and it was sloopy in the strut. OR you may have a bent strut. Did anyone wind up a dock line in the prop reciently. this could bent the shaft or strut. (mine bent with a crap trap line, had to replace the strut. if there are wear marks on the shaft where they go into the hull you wont be able to get it to align. These shafts have to be in very straight, within a few thousands of an inch. the flex coupling may hide a bigger problem. I would let them take it apart and see what you have. removing the strut is a pain in the tush but not rocket science.
The alignment should fix this if and only if the shaft is not riding on the tube thru the hull. This could be a big problem if its wearing thur the tube. so I think i would want to pull the shaft and look at the area where the shaft runs thru the hull while your at it. The previous post is correct in that you must align the shaft after it sets in the water for a while. but if the shaft is wearing like the picture then it could be the wrong alignment or the shaft if binding between the tube and the strut, or the shaft is bent, or the cutlass they put in was not the correct size and it was sloopy in the strut. OR you may have a bent strut. Did anyone wind up a dock line in the prop reciently. this could bent the shaft or strut. (mine bent with a crap trap line, had to replace the strut. if there are wear marks on the shaft where they go into the hull you wont be able to get it to align. These shafts have to be in very straight, within a few thousands of an inch. the flex coupling may hide a bigger problem. I would let them take it apart and see what you have. removing the strut is a pain in the tush but not rocket science.
Yep Brian, Looks like your engine is pointed too
low and to the port side of the boat. Everything starts at the strut. Think of the boat under construction. The strut is installed. It must point to where the engine is going to be. (within a few thousands of an inch) No amount of alignment can salvage poor strut placement. (Don't builders use laser pointers now? That would sure solve lots of problems) Anyway, as I read your account of the yards work and checked out your photo, I found myself nodding. Sounded like you were getting good scoop. But I question why the person who aligned your shaft in the past didn't tell you that your equipment was 'out-of-range' for proper adjustment. And the guys helping here are spot-on. It ain't rocket sci,,,,
low and to the port side of the boat. Everything starts at the strut. Think of the boat under construction. The strut is installed. It must point to where the engine is going to be. (within a few thousands of an inch) No amount of alignment can salvage poor strut placement. (Don't builders use laser pointers now? That would sure solve lots of problems) Anyway, as I read your account of the yards work and checked out your photo, I found myself nodding. Sounded like you were getting good scoop. But I question why the person who aligned your shaft in the past didn't tell you that your equipment was 'out-of-range' for proper adjustment. And the guys helping here are spot-on. It ain't rocket sci,,,,
Yep, this is how ours looked...
…on a 2005 H41. We snagged a crab trotline and apparently it was just enuf of a pull to yank our strut slightly askew to the point it looked just like yours does now. Our Hunter dealer realigned the strut without removing it, by using a fancy bending rig. Cost $500 including new cutlass. Trouble is, after all was done, we now had a slightly bent propshaft and so we pulled that this year and had it straightened for another $750. There is very little side-to-side adjustment room in the shaft log on these late model Hunters. You can easily check that by disconnecting the shaft at the coupling and then move the shaft up/down, side to side at the engine end. If someone is standing outside looking at the shaft in your cutlass while you move the shaft sideways to its maximum distance in the log, you will quickly see there is not enough space in the log to correct this particular problem by engine realignment alone. If you have not snagged anything on your propshaft to cause this strut misalign, there is a possibility it was just installed slightly askew at the factory. Either way, it’s correctable. While you are at it, I would definitely have someone check your shaft for straightness.
…on a 2005 H41. We snagged a crab trotline and apparently it was just enuf of a pull to yank our strut slightly askew to the point it looked just like yours does now. Our Hunter dealer realigned the strut without removing it, by using a fancy bending rig. Cost $500 including new cutlass. Trouble is, after all was done, we now had a slightly bent propshaft and so we pulled that this year and had it straightened for another $750. There is very little side-to-side adjustment room in the shaft log on these late model Hunters. You can easily check that by disconnecting the shaft at the coupling and then move the shaft up/down, side to side at the engine end. If someone is standing outside looking at the shaft in your cutlass while you move the shaft sideways to its maximum distance in the log, you will quickly see there is not enough space in the log to correct this particular problem by engine realignment alone. If you have not snagged anything on your propshaft to cause this strut misalign, there is a possibility it was just installed slightly askew at the factory. Either way, it’s correctable. While you are at it, I would definitely have someone check your shaft for straightness.
Shaft Log Position?
Although Hunter insists that they do not have a problem, I had two new boats (2001 320 & 2003 356) with misaligned shaft logs. The problem was how the holes were cut through the hull were so far off that the engine cound never align with the strut. The 320 had to have the shaft log rebedded, but the 356 was fixed by shimming the strut. The problem caused the strut on the 320 to break due to excessive sideways force, and there was a 1/8" groove cut in the shaft where it ran through the log. The shaft and strut were replaced, and the log was re-bedded to correct that problem. The 356 had the same problem, but was not as excessive. The strut was shimmed to correct the alignment. Try pulling the shaft and let it sit just in the strut and see where things line up. If the shaft does not easily fit through the center of the log, then something is off. I hope your problem isn't as bad as mine, but since you have to pull everything anyway, it might be a good idea to check it before you go through another Cutlass bearing. Steve
Although Hunter insists that they do not have a problem, I had two new boats (2001 320 & 2003 356) with misaligned shaft logs. The problem was how the holes were cut through the hull were so far off that the engine cound never align with the strut. The 320 had to have the shaft log rebedded, but the 356 was fixed by shimming the strut. The problem caused the strut on the 320 to break due to excessive sideways force, and there was a 1/8" groove cut in the shaft where it ran through the log. The shaft and strut were replaced, and the log was re-bedded to correct that problem. The 356 had the same problem, but was not as excessive. The strut was shimmed to correct the alignment. Try pulling the shaft and let it sit just in the strut and see where things line up. If the shaft does not easily fit through the center of the log, then something is off. I hope your problem isn't as bad as mine, but since you have to pull everything anyway, it might be a good idea to check it before you go through another Cutlass bearing. Steve
Thanks to all who responded. In reading about excessive cutlass wear the only cause I could find was motor misalignment. It seems that at least in some cases this can be due to strut or log misalignment as well. I am still not convinced my problem is with the strut. I think I will realign the motor after the boat is back in the water. If the problem persists I will have the strut realigned at next haul out. Thanks. Brian Matthews
Take a look
That IS a worn cutless. I suggest taking a close look at the other end of the bearing. If the strut is misaligned then the wear should be on the opposite side of the bearing. I had to remove the strut on my H376 for other reasons and, when putting it back thought to use the existing prop shaft as a guide. I was astounded to discover it sagged by about 1/4" between log tube and strut when unsupported. Even now the new alignment is not perfect and the shaft binds slightly - but that was all 8 years ago and I saw mine yesterday and it still shows no wear. I conclude that perfect alignment is not essential but gross misalignment is bound to cause trouble.
That IS a worn cutless. I suggest taking a close look at the other end of the bearing. If the strut is misaligned then the wear should be on the opposite side of the bearing. I had to remove the strut on my H376 for other reasons and, when putting it back thought to use the existing prop shaft as a guide. I was astounded to discover it sagged by about 1/4" between log tube and strut when unsupported. Even now the new alignment is not perfect and the shaft binds slightly - but that was all 8 years ago and I saw mine yesterday and it still shows no wear. I conclude that perfect alignment is not essential but gross misalignment is bound to cause trouble.
Hey Donalex! I've got one for you.
Imagine you're a kid in the early 70s. You've had a hotrod ski boat built with a V drive. The parts you couldn't do were all screwed up by the shop you paid to do tech work. Part of that was too much 'drop' in the strut as supplied by the shop. (the boat would ride nose down) Well, even back in those days I knew I could do a better job than the Marine Engineer that did the shoddy work. I bought a shorter strut, unbolted the V drive and went to work. The monel shaft was 157" long! And only 1" in diameter. Now THAT'S sag. But when I was finished it was close. I even had an adjustable V drive when finished. That was more than the engineer built for me. And get this. First launch. I started the engine and put it in gear. (New boat before strut work) The aluminum channel beam that runs athwart-ship holding the top of the rudder TORE LOSE. It's job is to resist the prop-wash that makes a rooster-tail. It's known as a strong-back. The engineer installed it with two #10 bronze wood screws. It should have had four 3/8 machine bolts. He went out of business but it took five years. He switched to making sailboats. What's that tell you?
Imagine you're a kid in the early 70s. You've had a hotrod ski boat built with a V drive. The parts you couldn't do were all screwed up by the shop you paid to do tech work. Part of that was too much 'drop' in the strut as supplied by the shop. (the boat would ride nose down) Well, even back in those days I knew I could do a better job than the Marine Engineer that did the shoddy work. I bought a shorter strut, unbolted the V drive and went to work. The monel shaft was 157" long! And only 1" in diameter. Now THAT'S sag. But when I was finished it was close. I even had an adjustable V drive when finished. That was more than the engineer built for me. And get this. First launch. I started the engine and put it in gear. (New boat before strut work) The aluminum channel beam that runs athwart-ship holding the top of the rudder TORE LOSE. It's job is to resist the prop-wash that makes a rooster-tail. It's known as a strong-back. The engineer installed it with two #10 bronze wood screws. It should have had four 3/8 machine bolts. He went out of business but it took five years. He switched to making sailboats. What's that tell you?
356/36 bearing wear
Hey Brian, we had a similar problem on our '02 356. our wear was completely in the vertical plane. after several alignment passes and a careful inspection of the strut, we theorized that Hunter/Yanmar used really soft rubber bushing on the mounts to reduce vibration transfer to the hull, resulting in a lot of movement that wore the cutless quickly. we installed a flex coupling from PYI last year and have no additional bearing wear. In additojn, the drivetrain seems much smoother than before. the only issue was that it's a tight fit between the transmission flange and the stuffing box.
Hey Brian, we had a similar problem on our '02 356. our wear was completely in the vertical plane. after several alignment passes and a careful inspection of the strut, we theorized that Hunter/Yanmar used really soft rubber bushing on the mounts to reduce vibration transfer to the hull, resulting in a lot of movement that wore the cutless quickly. we installed a flex coupling from PYI last year and have no additional bearing wear. In additojn, the drivetrain seems much smoother than before. the only issue was that it's a tight fit between the transmission flange and the stuffing box.
bent shaft
No one seemed to have mentioned another possibllity namely a bent shaft. If you keep having problems you will need to have it pulled and checked.
No one seemed to have mentioned another possibllity namely a bent shaft. If you keep having problems you will need to have it pulled and checked.
Pete, Ed did.
And it warrants pointing out again. Several guys have mentioned lines caught around their shafts that bent the strut. My strut survived several lines since new in '86) but the shaft didn't. Hunter built my boat with a bronze shaft. Reason? Cheap. I replaced it in Key West with a monel shaft that is still perfect today, (Of course! They're lifetime shafts) Cost? $140.00.
And it warrants pointing out again. Several guys have mentioned lines caught around their shafts that bent the strut. My strut survived several lines since new in '86) but the shaft didn't. Hunter built my boat with a bronze shaft. Reason? Cheap. I replaced it in Key West with a monel shaft that is still perfect today, (Of course! They're lifetime shafts) Cost? $140.00.
drive system alignment
For those interested found this online. Excellent discussion of the causes of misalignment.
For those interested found this online. Excellent discussion of the causes of misalignment.
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