We own an 88 Cat 30 that we have completely reconditioned over the past two years; however, we are still chasing one last annoying issue. When under power we hear a loud rattling sound at various RPMs. The sound is a clacking sound, almost like slapping two boards together. It is easily audible and occurs only when in gear. It does not occur at all rpms and is avoidable if I stay out of the rpm ranges where it occurs. Otherwise the boat runs well under power, no issues, vibrations etc. I use a very good local mechanic and we have checked the motor mounts, cutlass bearing, prop, shaft alignment, even put a diver under the boat while it was running in gear tied in the slip. The diver didn't see any excessive vibration in the prop, prop shaft etc. We’re running out of places to look and things to check. Any ideas or experience with this problem would be greatly appreciated.
Rattle Under Power
- Thread starter arkayp
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Galley?
This is probably too obvious, but I've endured annoying rattling from the burners on the stovetop at certain RPMs. The galley in general is a good place to look as it seems there are several culprits that aren't secured very well. Just a thought... best of luck! Trevor
This is probably too obvious, but I've endured annoying rattling from the burners on the stovetop at certain RPMs. The galley in general is a good place to look as it seems there are several culprits that aren't secured very well. Just a thought... best of luck! Trevor
San Diego, CA 04/25 at 05:09PM Catalina 30 Rattle Under Power
Thanks, that is exactly what it sounds like. The first thing I checked was the stove without success. I'm going to check it again, but I'm real sure it is coming from somewhere else. Hard to track the sound when underway.
Thanks, that is exactly what it sounds like. The first thing I checked was the stove without success. I'm going to check it again, but I'm real sure it is coming from somewhere else. Hard to track the sound when underway.
Sounds Like Shaft Misalignment
We have an '88 model and I am trying to invision everything aboard that could rattle! If its not the drivetrain (alignment, cutlass, transmission or mounts, etc) then its hard to figure why something would rattle without the drivetrain being the root cause. With that I would proceed with waiting til the noise showed up again and go below and check from v-berth to transom isolating the noise and problem. Thats all you can do. Who knows; maybe its a rattling anchor fluke, water pump slapping from loose mount, busted or misaligned bildge pump impellor? Good luck and please let us know. Bob '88 Cat 30
We have an '88 model and I am trying to invision everything aboard that could rattle! If its not the drivetrain (alignment, cutlass, transmission or mounts, etc) then its hard to figure why something would rattle without the drivetrain being the root cause. With that I would proceed with waiting til the noise showed up again and go below and check from v-berth to transom isolating the noise and problem. Thats all you can do. Who knows; maybe its a rattling anchor fluke, water pump slapping from loose mount, busted or misaligned bildge pump impellor? Good luck and please let us know. Bob '88 Cat 30
rattle ?
I have a 1988 C30 TR my boat acts funny if my rig is not tuned just right.I adjust the upper and lower stays just wright for sailing.It sails real good at the losse gage seting max working load or bit tighter .I have no backstay adjuster i removed the back stay Adjuster becouse the stays go thru the bimine.I started geting funny noise when i would lighten the load on the rig when not sailing.I would adjust (one turn buckel)five turns .If i started motering before i adjusted the rig i would get some vibe at some RPMs or if going into a swell the boat flex mite start some noise. I think that if you twist the back of the boat you could get your noise.I dont adjust my shaft with the mounts i adjust with the rig wial runing.It works real sweet .You cant adjust for waves and prop tork at the dock John
I have a 1988 C30 TR my boat acts funny if my rig is not tuned just right.I adjust the upper and lower stays just wright for sailing.It sails real good at the losse gage seting max working load or bit tighter .I have no backstay adjuster i removed the back stay Adjuster becouse the stays go thru the bimine.I started geting funny noise when i would lighten the load on the rig when not sailing.I would adjust (one turn buckel)five turns .If i started motering before i adjusted the rig i would get some vibe at some RPMs or if going into a swell the boat flex mite start some noise. I think that if you twist the back of the boat you could get your noise.I dont adjust my shaft with the mounts i adjust with the rig wial runing.It works real sweet .You cant adjust for waves and prop tork at the dock John
Look at your exhaust hose
when I moved mine (needed to get at the under side of the winch) and allowed it to touch the hull (in the lazarette), it vibrated and made a horrible rattle at some reproducible engine speeds. It used to be held away from the hull with a specalized wire tie that connected to and hung from a bolt (screw?) under the side deck. Steve Alchemist C-30T #4764 ('87)
when I moved mine (needed to get at the under side of the winch) and allowed it to touch the hull (in the lazarette), it vibrated and made a horrible rattle at some reproducible engine speeds. It used to be held away from the hull with a specalized wire tie that connected to and hung from a bolt (screw?) under the side deck. Steve Alchemist C-30T #4764 ('87)
use a pss shaft seal?
there has been some talk about the pss shaft seal "allowing" shaft vibration as unlike a normal shaft packing the dripless seal does not actually support the shaft so it is unsupported from the transmission to the cutlass bearing. May be more about this in archives. THis is not a complaint about the pss seal - I have one and love it.
there has been some talk about the pss shaft seal "allowing" shaft vibration as unlike a normal shaft packing the dripless seal does not actually support the shaft so it is unsupported from the transmission to the cutlass bearing. May be more about this in archives. THis is not a complaint about the pss seal - I have one and love it.
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