I have considerable vibration noise coming from deep down in the hull in the aft of the boat on hard exceleration, which increases as rpms increase. It started about two months after the boat was commissioned and has gotten worse over time. It's kind of a high frequency buzzing sound, which is very loud. No vibration noise is present in either neutral or reverse gear. The shaft is aligned properly and nothing is wrapped on the prop and it is undamaged. The cutlass bearing seems to be ok. Catalina thinks it may either be cavitation or some sort of inherent prop problem. They are going to change props on another C350 which has this same problem to see what happens. They are also investigating other possible causes. My prop is a factory supplied 3 blade cruising prop which was sold as an option. What kind of prop do you have on your C350? Does your boat have this problem? Thanks for any feedback. B. Dehuff C350 #116
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Tom
what kind of shaft packing
Blair do you and the other 350 with the problem both have a drippless seal on your shaft? There was a thread a year or more ago about a variety of boats with a vibration problem when at higher rpms, sort of a "buzzing" as if someone was rapping on the bottom of the hull quickly. A common denominator was they all had dripless seals somebody though that there might be more vibration because the dripless seal doesn't support the shaft between the coupling and the cutlass bearing like regular shaft packing and the shaft could vibrate against the hull shaft exit hole. This is not a complaint about dripless seals - I love mine, I have it on a cat 30 and the vibration problem I had is rare - may be once a season, This may not be your problem if it is a repetative thing whenever you use the boat but I thought I'd pass this anecdote along.
Blair do you and the other 350 with the problem both have a drippless seal on your shaft? There was a thread a year or more ago about a variety of boats with a vibration problem when at higher rpms, sort of a "buzzing" as if someone was rapping on the bottom of the hull quickly. A common denominator was they all had dripless seals somebody though that there might be more vibration because the dripless seal doesn't support the shaft between the coupling and the cutlass bearing like regular shaft packing and the shaft could vibrate against the hull shaft exit hole. This is not a complaint about dripless seals - I love mine, I have it on a cat 30 and the vibration problem I had is rare - may be once a season, This may not be your problem if it is a repetative thing whenever you use the boat but I thought I'd pass this anecdote along.
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Bill
After Acceleration
You said you have the vibration after hard acceleration. Does the viberation continue once its started or does it abate as the boat comes up to speed?
You said you have the vibration after hard acceleration. Does the viberation continue once its started or does it abate as the boat comes up to speed?
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Blair Dehuff
Thanks for you responses. The vibration noise continues once it starts and does not abate as the boat comes up to speed. I don't know if all C350's have a dripless seal, but the other C350's with this problem (3 at my dealer)all have dripless seals. The Catalina factory and my dealer are checking out several possible causes: prop, shaft, bearing, cavitation, and harmonic resonance. They are thinking about alternating different props on the same boat with this problem to see what happens. The noise is just as you described - kind of high pitched buzzing and rapid pounding sound coming from deep within the hull. On my boat the vibration noise is not present when the engine is in neutral or reverse gear. I even ran the engine up to 3000 rpm in forward gear with the boat tied to the dock, and there was no vibration noise at all. It seems that the noise begins only when the boat starts moving forward in the water. The more load you put on it (such as wind and waves) the louder it gets.
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Bob
do you have a cone zinc on your prop shaft
I was told that the cone zinc on the end of the prop shaft can rattle when worn (depleted). This could be the cause of your harmonics and does explain why the noise didn't start until you had the boat for awhile.
I was told that the cone zinc on the end of the prop shaft can rattle when worn (depleted). This could be the cause of your harmonics and does explain why the noise didn't start until you had the boat for awhile.
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Blair Dehuff
Cone Zinc
Bob, Thanks, I will check it out. The vibration noise started 2 months after the boat was commissioned. My boat is in fresh water. Should the zinc wear so fast? Maybe it's just become loose for some reason?
Bob, Thanks, I will check it out. The vibration noise started 2 months after the boat was commissioned. My boat is in fresh water. Should the zinc wear so fast? Maybe it's just become loose for some reason?
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JeffC
Alignment
I had a similar noise on my C320. It was caused by the shaft vibrating against the stuffing box tube. This happened because the engine was set too low on its mounts and the shaft was not centered in the tube. I had to raise all four mounts to center the shaft, and then realign the flanges. No more vibe. JeffC
I had a similar noise on my C320. It was caused by the shaft vibrating against the stuffing box tube. This happened because the engine was set too low on its mounts and the shaft was not centered in the tube. I had to raise all four mounts to center the shaft, and then realign the flanges. No more vibe. JeffC
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Bob
Cone zinc
Zincs would not deplete in fresh water and usually are not installed during commissioning when they know the boat will be used in fresh water only.
Zincs would not deplete in fresh water and usually are not installed during commissioning when they know the boat will be used in fresh water only.
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Chick
Dripless Seal Problem?
I had a similar problem and wrote my solution to it about mid summer (2003). When underpower, a banging vibration came from the aft end. Eventually, I discovered that the dripless seal was vibrating/slipping. The manufacturer said to open the seal and use 600 grit sandpaper folded in half to smooth out the two sides (carbon and steel) of the seal. This worked fine and I've had 100% success to date. The manufacturer also said that toothpaste placed between the carbon and metal will cause the same good result. This was a very troubling problem that I could never make happen...it only happened randomly but is, thankfully, gone.
I had a similar problem and wrote my solution to it about mid summer (2003). When underpower, a banging vibration came from the aft end. Eventually, I discovered that the dripless seal was vibrating/slipping. The manufacturer said to open the seal and use 600 grit sandpaper folded in half to smooth out the two sides (carbon and steel) of the seal. This worked fine and I've had 100% success to date. The manufacturer also said that toothpaste placed between the carbon and metal will cause the same good result. This was a very troubling problem that I could never make happen...it only happened randomly but is, thankfully, gone.
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Richard
Vibration Woes
Hi Blair, Are you sailing on Lake Tahoe in January? I thought the lake would freeze. I have pretty much the same vibration problem, previously listed here as well as on SailNet. I also have the three blade prop, the PSS shaft seal and a wing keel. I also have a 5KW generator installed that weighs the stern down a little. It might be helpful to know the configuration of 350s that have this problem and those that don't. So 350 folks, please respond with Vibration Problem: Yes or No Dripless Packing Gland: Yes or No Prop Type: Three blade, Two Blade, Other Keel Type: Wing or Fin Boat Trim: Anything Altering the Fore/AftTrim Maybe we will find a correlation. If the vibration exists on some 350s and not others and if it appears after a few months or 20-30 hours on the engine, I just don't understand how it can be problem with the prop design. it seems like something must have changed. Last year, someone reported that the cutlass bearing rotating in the bearing housing was a common problem with 350s but my dealer checked with Catalina to find that Catalina has found only one instance of ths problem. I will post this on SailNet as well in hope that I can get enough feed back to determine if something correlates with the problem. Good Luck and kee us posted on what you find out from Catalina. Thanks Richard & Joanne Collins s/v Eagle's Wings C350 #37
Hi Blair, Are you sailing on Lake Tahoe in January? I thought the lake would freeze. I have pretty much the same vibration problem, previously listed here as well as on SailNet. I also have the three blade prop, the PSS shaft seal and a wing keel. I also have a 5KW generator installed that weighs the stern down a little. It might be helpful to know the configuration of 350s that have this problem and those that don't. So 350 folks, please respond with Vibration Problem: Yes or No Dripless Packing Gland: Yes or No Prop Type: Three blade, Two Blade, Other Keel Type: Wing or Fin Boat Trim: Anything Altering the Fore/AftTrim Maybe we will find a correlation. If the vibration exists on some 350s and not others and if it appears after a few months or 20-30 hours on the engine, I just don't understand how it can be problem with the prop design. it seems like something must have changed. Last year, someone reported that the cutlass bearing rotating in the bearing housing was a common problem with 350s but my dealer checked with Catalina to find that Catalina has found only one instance of ths problem. I will post this on SailNet as well in hope that I can get enough feed back to determine if something correlates with the problem. Good Luck and kee us posted on what you find out from Catalina. Thanks Richard & Joanne Collins s/v Eagle's Wings C350 #37
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Kevin
Cavatation a real possibility
You need to imagine what the prop is doing.... After spending some time around the undersides of catalinas, imagine a three bladed prop winding up rapidly. First, a three bladed prop is not the best design for propulsion with diameters less than 24in. The second blade seems to constantly cancel out the third. This would likely cause an unequal amount of wash throughout rotation of the prop. Secondly, consider the angle of the shaft in relation to the forward movement of the boat. They are not parallel. The prop wants to travel slightly upward. The argument between the two could result in pressure differences, which could again, cause cavitation. Thirdly, the 350 Catalina's new skeg design appears to be about 3.5 to 4in. wide, and of course, one-half the diameter of the prop. This in itself probably cancels out any free flow of water to the prop thus setting up for cavitation more so than the other reasons. It makes sense that there is no noise while in reverse. There is little or no obstructed water flow to the prop. Although I am in love the the 350, and am currently scamming a way to afford one, this is one area that concerns me greatly. I wonder if Catalina will examine complaints such as yours, and what will they do about it. I agree that changing to a two bladed prop will help. Each blade will have a longer stroke through clear water before it is disrupted by the skeg. However, you may experiment with applying throttle very slowly to avoid cavitation. Record if it only happens when you power on rapidly, or does if cavitate in a chop. At any rate, I too will be listening for results. Kev
You need to imagine what the prop is doing.... After spending some time around the undersides of catalinas, imagine a three bladed prop winding up rapidly. First, a three bladed prop is not the best design for propulsion with diameters less than 24in. The second blade seems to constantly cancel out the third. This would likely cause an unequal amount of wash throughout rotation of the prop. Secondly, consider the angle of the shaft in relation to the forward movement of the boat. They are not parallel. The prop wants to travel slightly upward. The argument between the two could result in pressure differences, which could again, cause cavitation. Thirdly, the 350 Catalina's new skeg design appears to be about 3.5 to 4in. wide, and of course, one-half the diameter of the prop. This in itself probably cancels out any free flow of water to the prop thus setting up for cavitation more so than the other reasons. It makes sense that there is no noise while in reverse. There is little or no obstructed water flow to the prop. Although I am in love the the 350, and am currently scamming a way to afford one, this is one area that concerns me greatly. I wonder if Catalina will examine complaints such as yours, and what will they do about it. I agree that changing to a two bladed prop will help. Each blade will have a longer stroke through clear water before it is disrupted by the skeg. However, you may experiment with applying throttle very slowly to avoid cavitation. Record if it only happens when you power on rapidly, or does if cavitate in a chop. At any rate, I too will be listening for results. Kev
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Blair Dehuff
C350 Vibration Woes
Thanks to everyone for the comments / suggestions. My boat is pretty much frozen in at Lake Tahoe at the present time (can't wait until spring), so I have to rely on my dealer Farallone Yachts in Alameda, CA to do some testing on other C350's with the same problem. I spoke with Frank Butler and Gerry Douglas at Catalina's factory earlier this week about this issue. They seem to realize that this may not an isolated problem with just a few C350's. I have taken the liberty of copying the various comments and ideas, and I have emailed them to the commissioning specialist at Farallone Yachts while he explores this problem. I also like the idea of the survey which was initiated by Richard. All this will be good info for Catalina. Any input which people may also wish to send directly to Frank Butler (Frank@catalinayachts.com)and/or Gerry Douglas (Gerard@catalinayachts.com) may also help to focus Catalina's further attention and efforts toward a solution to the vibration problem. Blair Dehuff C350 #116 Lake Tahoe
Thanks to everyone for the comments / suggestions. My boat is pretty much frozen in at Lake Tahoe at the present time (can't wait until spring), so I have to rely on my dealer Farallone Yachts in Alameda, CA to do some testing on other C350's with the same problem. I spoke with Frank Butler and Gerry Douglas at Catalina's factory earlier this week about this issue. They seem to realize that this may not an isolated problem with just a few C350's. I have taken the liberty of copying the various comments and ideas, and I have emailed them to the commissioning specialist at Farallone Yachts while he explores this problem. I also like the idea of the survey which was initiated by Richard. All this will be good info for Catalina. Any input which people may also wish to send directly to Frank Butler (Frank@catalinayachts.com)and/or Gerry Douglas (Gerard@catalinayachts.com) may also help to focus Catalina's further attention and efforts toward a solution to the vibration problem. Blair Dehuff C350 #116 Lake Tahoe
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