Last year before buying my 1992 H37.5 I noticed during the sea trial a significant amount of vibration in the shaft and the prop. This was also noted by the surveyor and by the guy who did the engine inspection. Their recommendation was to have the shaft aligned and to pull the max prop and send it to PYI for servicing. We followed both of those recommendations and reinstalled the original fixed blade prop while the max prop was at PYI. Presto! The vibration problem was gone. The max prop came back from PYI some time ago, but I delayed reinstalling it until the annual haulout and bottom work which was concluded last week. So now the max prop is back on and guess what else is back--the vibration. The max prop was installed by a very highly regarded yard to settings supplied by PYI for my specific model of Yanmar. I'm kind of at a loss as to what to do. I'm unhappy and the mate is VERY unhappy with the vibration. I guess I can put the old prop back on, but that seems like a waste of what should be a very nice feathering prop. Any suggestions will be appreciated. Gary Wyngarden S/V Wanderlust H37.5
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lifting straps
It worked fine before, but now, after hauling again, you have problems? Maybe a lifting strap got caught on the strut, shaft, or prop, and tweaked it out of alignment again. Were you there when the boat was both hauled & launched, and did you check the placement of the straps? On our last haulout we were on the way up when the operator thought he'd better drop us back down a tad, slide the staps a bit, and try again. Even a little twitch from a 20 Ton travellift can bend a 1" steel rod like a pretzle. Uneven marine growth on the blades can also cause vibration, or, depending upon the design, make the blades open unevenly, which leads to vibrations too. You have lots of options. Have fun exploring and eliminating them one by one!
It worked fine before, but now, after hauling again, you have problems? Maybe a lifting strap got caught on the strut, shaft, or prop, and tweaked it out of alignment again. Were you there when the boat was both hauled & launched, and did you check the placement of the straps? On our last haulout we were on the way up when the operator thought he'd better drop us back down a tad, slide the staps a bit, and try again. Even a little twitch from a 20 Ton travellift can bend a 1" steel rod like a pretzle. Uneven marine growth on the blades can also cause vibration, or, depending upon the design, make the blades open unevenly, which leads to vibrations too. You have lots of options. Have fun exploring and eliminating them one by one!
Performance loss?
Hi Gary - Bummer about the Max prop issue. The only problem I've ever heard about with regards to Max props comes from incorrect pitch. Are you able to get up to normal RPMs with the max prop? Unfortunately, these props can require pitch tinkering, which is not convenient, to say the least. It's likely the pitch is off, as even one notch can make a difference. The folks at PYI are usually right on, but they're not infallible. Also, the yard may have not set it right (even the reputable ones have turnover and you may not know who actually installed the prop). It's a pain the derrier, but I wouldn't give up on it - they are great props once set up. Short of hauling, I can suggest maybe contacting Dwayne of Emerald City Diving, who has worked on Max props for many years underwater (I'm still amazed how he can avoid dropping parts!). Emerald City Diving can be reached at 206-789-3000. Best of luck! Trevor
Hi Gary - Bummer about the Max prop issue. The only problem I've ever heard about with regards to Max props comes from incorrect pitch. Are you able to get up to normal RPMs with the max prop? Unfortunately, these props can require pitch tinkering, which is not convenient, to say the least. It's likely the pitch is off, as even one notch can make a difference. The folks at PYI are usually right on, but they're not infallible. Also, the yard may have not set it right (even the reputable ones have turnover and you may not know who actually installed the prop). It's a pain the derrier, but I wouldn't give up on it - they are great props once set up. Short of hauling, I can suggest maybe contacting Dwayne of Emerald City Diving, who has worked on Max props for many years underwater (I'm still amazed how he can avoid dropping parts!). Emerald City Diving can be reached at 206-789-3000. Best of luck! Trevor
P.S.
P.S. We've also found with our maxprop that to make sure the blades are opened all the way, it helps to put it into reverse first, listen for the blades to "clunk" open, and then quickly shift into forward and increase throttle.
P.S. We've also found with our maxprop that to make sure the blades are opened all the way, it helps to put it into reverse first, listen for the blades to "clunk" open, and then quickly shift into forward and increase throttle.
Gary,
I am sorry that your much desired cruising is being stalled. Gary, Sometimes being on land effects the hull shape...stringers...shaft alignment. It may take a week or more for the hull to settle back to shape after a haulout. To eliminate an unneeded haulout, make sure it is not a shaft alignment, loosen the bolts (normally 4 of them) on the propellershaft to transmission connection. Carefully open this connection and use feeler gages to test at each bolt in the connection. The gaging should be very close. if it is, the prop is the problem. If the gaging proves to be very different, it could be engine/shaft alignment. Approx.time to do this is about 2 hours. If you are not sure how to do this, maybe one of the local service crew would show up for two hours pay to check it out at his offtime rate with beverage. If it is the prop, I would go with some of the previous advice, since the Max prop is a specialized item. The diver that knows the Max prop sounds like the good alternative. best wishes r.w.landau
I am sorry that your much desired cruising is being stalled. Gary, Sometimes being on land effects the hull shape...stringers...shaft alignment. It may take a week or more for the hull to settle back to shape after a haulout. To eliminate an unneeded haulout, make sure it is not a shaft alignment, loosen the bolts (normally 4 of them) on the propellershaft to transmission connection. Carefully open this connection and use feeler gages to test at each bolt in the connection. The gaging should be very close. if it is, the prop is the problem. If the gaging proves to be very different, it could be engine/shaft alignment. Approx.time to do this is about 2 hours. If you are not sure how to do this, maybe one of the local service crew would show up for two hours pay to check it out at his offtime rate with beverage. If it is the prop, I would go with some of the previous advice, since the Max prop is a specialized item. The diver that knows the Max prop sounds like the good alternative. best wishes r.w.landau
That's Wierd
That's really wierd. The comments before were all good ones but the being off on a tooth really makes sense. When you handed the prop over to PYI and told them about the problem did they have anything to say? By the way, to my knowledge they don't do any brazing or reworking of metal there, they take that work over to The Prop Shop: http://www.propshopltd.com/ When I take mine apart and put it back together I always check the angle of the blades to make sure they are equal because that way I'm pretty assured of being on the right pitch. With three blades maybe one could have been put in one tooth off? That's a really tough one. Is there any water clear enough to see the prop where you are? I'm thinking someone on the inside of the boat could slowly rotate the prop shaft and you could check the angle on each blade.
That's really wierd. The comments before were all good ones but the being off on a tooth really makes sense. When you handed the prop over to PYI and told them about the problem did they have anything to say? By the way, to my knowledge they don't do any brazing or reworking of metal there, they take that work over to The Prop Shop: http://www.propshopltd.com/ When I take mine apart and put it back together I always check the angle of the blades to make sure they are equal because that way I'm pretty assured of being on the right pitch. With three blades maybe one could have been put in one tooth off? That's a really tough one. Is there any water clear enough to see the prop where you are? I'm thinking someone on the inside of the boat could slowly rotate the prop shaft and you could check the angle on each blade.
Max-prop
With max prop (PYI) checking the balance and your yard, etc. verifying the alignment to rule out shaft whip etc. , I's strongly suggest that whoever re-installed the max prop back on didnt match the parts correctly (every mating surface has an index mark .... A B C etc.) OR one of the blades is off by ONE gear tooth. If you're not careful and knowledgeable with such assembly, such 'mis-match' mistakes are easy. The result is that perhaps ONE blade is set to a different pitch than the rest. A diver would be able to tell if ONE blade is set wrong .... although it may not be that noticeable when the prop blades swing to reverse mode. Just like just about ALL 'yard-work' these days, its usually better to do it yourself or at least 'verify' the yard work before the boat goes into the water.
With max prop (PYI) checking the balance and your yard, etc. verifying the alignment to rule out shaft whip etc. , I's strongly suggest that whoever re-installed the max prop back on didnt match the parts correctly (every mating surface has an index mark .... A B C etc.) OR one of the blades is off by ONE gear tooth. If you're not careful and knowledgeable with such assembly, such 'mis-match' mistakes are easy. The result is that perhaps ONE blade is set to a different pitch than the rest. A diver would be able to tell if ONE blade is set wrong .... although it may not be that noticeable when the prop blades swing to reverse mode. Just like just about ALL 'yard-work' these days, its usually better to do it yourself or at least 'verify' the yard work before the boat goes into the water.
Major or Minor Vibrations?
Gary: I would suggest strongly that you take RW's advice before you go so far as to having your boat hauled again. It is certainly the cheapest way out of this if it works. The best I remember, might be wrong here, I believe that the clearances are supposed to be as close as .0010. I've developed minor vibrations a couple of times after haul outs and had to spend an hour or two balled up in the engine compartment adjusting it out. I've gotten so that I check the alignment after every haul out. Luck with it!
Gary: I would suggest strongly that you take RW's advice before you go so far as to having your boat hauled again. It is certainly the cheapest way out of this if it works. The best I remember, might be wrong here, I believe that the clearances are supposed to be as close as .0010. I've developed minor vibrations a couple of times after haul outs and had to spend an hour or two balled up in the engine compartment adjusting it out. I've gotten so that I check the alignment after every haul out. Luck with it!
Hull Creep
Since the boat was out of the water for a while it's very possible that there was some creep in the hull from the blocking. If this is the cause then then one would assume that the nature of the bad vibes should change with time as the hull resumes it's normal shape. If there is no change then it's more likely that it is something mechanical in nature.
Since the boat was out of the water for a while it's very possible that there was some creep in the hull from the blocking. If this is the cause then then one would assume that the nature of the bad vibes should change with time as the hull resumes it's normal shape. If there is no change then it's more likely that it is something mechanical in nature.
Gary,
Because the first rule in problem solving is to ask 'what change was made?', well, go ahead and check the alignment but my money is on the prop. I'm sure you know a reasonably priced diver. The 'check' on MaxProps is to turn the blades so they are half way between forward and reverse. Then looking edgewise, all blades have to be perfectly flat to each other. We're rootin' for you.
Because the first rule in problem solving is to ask 'what change was made?', well, go ahead and check the alignment but my money is on the prop. I'm sure you know a reasonably priced diver. The 'check' on MaxProps is to turn the blades so they are half way between forward and reverse. Then looking edgewise, all blades have to be perfectly flat to each other. We're rootin' for you.
Just a thought
If the cone angle of the MaxProp does not match that of the shaft, it is possible and very likely that the prop would not be centered and cause the vibration you observe. Other possible cause of the same problem could be the key that prevents the prop from rotating over the shaft could be too thick. To check this you would need to mark to current depth at which the prop sits on the shaft before you remove it. Then you take the key out and remount the prop. If you find the prop now sits deeper in the shaft, then the key is too large (thick) and you need to file it. Good luck
If the cone angle of the MaxProp does not match that of the shaft, it is possible and very likely that the prop would not be centered and cause the vibration you observe. Other possible cause of the same problem could be the key that prevents the prop from rotating over the shaft could be too thick. To check this you would need to mark to current depth at which the prop sits on the shaft before you remove it. Then you take the key out and remount the prop. If you find the prop now sits deeper in the shaft, then the key is too large (thick) and you need to file it. Good luck
Another thought
Gary, Maybe you should spring for the diver and have a yard rep. there when he brings the prop up. Have the yard pay the diver if it is their mistake. r.w.landau
Gary, Maybe you should spring for the diver and have a yard rep. there when he brings the prop up. Have the yard pay the diver if it is their mistake. r.w.landau
I agree with Jose!!
I put my Max prop on without getting the core perfectly set. Had a lot of vibration. Talked with the people at Max prop and believe that's what was wrong. Mark where it sits without the key and make sure it goes on that far with the key.
I put my Max prop on without getting the core perfectly set. Had a lot of vibration. Talked with the people at Max prop and believe that's what was wrong. Mark where it sits without the key and make sure it goes on that far with the key.
forgot to add this
I took off the Max prop, put the old prop back on. and no more vibration. Bet that's the problem! RG Miller
I took off the Max prop, put the old prop back on. and no more vibration. Bet that's the problem! RG Miller
Thanks, guys.
Thanks, guys. Sorry to be slow on the uptake, but I spent the day in Alachua, FL with Hunter Marine yesterday. (More on this later.) You've given me some ideas to work on for which I am grateful. I'll keep you posted as to what happens. Gary Wyngarden S/V Wanderlust H37.5
Thanks, guys. Sorry to be slow on the uptake, but I spent the day in Alachua, FL with Hunter Marine yesterday. (More on this later.) You've given me some ideas to work on for which I am grateful. I'll keep you posted as to what happens. Gary Wyngarden S/V Wanderlust H37.5
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