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Greetings to all from a newbie '95 PSC 31 owner. After a 600NM delivery trip from southern Japan to Yokohama, I am thrilled to finally have the boat docked snug in my homeport after two months since starting the deal.

Caretta is a beautiful boat in decent-ish condition. A little cleaning and tidying about will bring out the beauty beneath, I'm certain. The odds and ends of the boat tell even a novice like me that the previous owner didn't give it much love, so my list of to-do's is extensive. Hopefully I can squeeze in some sail-time in between.

I'm hoping that the forum user will suffer some elementary questions I have:

There's a clanking drive noise at around 1400rpm coming from right beneath the aftmost cockpit locker. It becomes discernible at 1200, peaks at 1400 and is gone above 1600. Under power, the boat and drive purr contently along at cruising engine speeds(fuel consumption was 1.83l/hour at about 2200-2500, 5.5knots average, btw). It almost sounds as if it's coming from the propeller, which is located right beneath the pedestal, although I do understand that noises don't always come from the apparent direction they're heard of.
Anyway, where should I start looking to find the cause of this noise? I've already cleaned out the aft cockpit locker just to make sure some metal object wasn't resonating with some rpm-specific vibration.

Another question: I want to add sheet bags and a winch handle case in the cockpit; what kind of hardware do I use when working with FRP? Sheet screws or bolts? Drill holes, through bolt and caulk? Do I need backing support?
 

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Maine Dub
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As for the clanking under power, check the prop for any side play and while down there see if there is any wiggle in the rudder. Enjoy your new boat.:)
 

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All engine systems have resonance frequencies (RPM levels) where the vibration and motion is greatest.

I would recommend running the engine dockside at the "noisy" speed with the transmission both in neutral and (lines doubled-slowly raise speed) in forward gear to evaluate whether the noise is engine or drive train related.

Also I would check every locker in the aft part of the boat to see if some metal items are clanging together.

I would physically check all attached items on the engine including the air filter housing/alternator and brackets and belt covers/decompression levers to make sure there is no "play" in them...and also push laterally and radially on the shaft equipment to check for excessive play.

I would swim the shaft equipment for a visual inspection to make sure I haven't picked up some fishing equipment on the shaft that is banging against the prop or other metal part of the boat.

I haven't listed these in the order I would do them but in the order they came to mind...

Congratulations on your boat ownership and your choice of boat.

Did you miss Typhoon Neoguri? I hope you were watching it closely and had plans for its arrival where you were...at sea or in port.

Good luck...
 

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Also possible (but not all that likely) it could be a loose prop zinc. Easy to eliminate with just a quick jump in even without a mask and fins.

John Watermark
PSC 31 #28
 

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Discussion Starter #6
Thanks all for the pointers and apologies for a belated reply.

Spent half a day and had a good look at the drivetrain. Turns out that the problem is more extensive than I initially thought it to be. I found that the rear engine mounts and the propeller shaft bearings were worn down. 1400rpm just happened to be the magic number at which the shaft would dance around the most and it was slack at other rpm's as well, although to a significantly lesser degree. Looks like my boat is getting hauled to get the engine mounts and shaft bearings replaced.

PS: Managed to arrive in port a couple of days before Noeguri came our way, so I had plenty of time to snug her down tight.
 
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