Rumble, rumble, snap, clunk

[backman]

Thats the sound of a shaft giving way and breaking off in Nantucket Sound 8 miles from my dock. 1.33 hr's at 6 knots on one engine.

On the plus side it was 92 nmiles from where we were fishing this afternoon.

I await forensic results when the boat is hauled; but a quick dip showed it gone right behind the strut.

My suspicion is that running the boat at 26 knots in a cresting following swell coming off the side that snapped was a contributing factor. The snap occured one minute after I made a 45 degree turn which changed the seas from coming off the port stern quarter to the port beam.

I was really leaning into the wheel to make the course correction; the boat came around grudgingly, leveled off on the new course and the port shaft snapped.

I will post root cause when it is determined.

[Split Decision]

Scary feeling, is'nt it.

A good friend of mine had a single screw Shamrock diesel. Went to the Hudson which was a 90mi run 1 way and felt a vibration on the way home. The next day we wanted to pull his boat to check it out. He started it to bring it to the ramp put it in gear and nothing happened. The shaft broke at the dock by the strut. At least he got his wheel back.

[TwinFin]

Scary event

Scary Larry. Glad you were close to home.

Were your shafts new - ie replaced with the repower? Our shafts are painted at the factory (or at least mine were). I've wondered about the paint prohibiting a good visual inspection. My yard seemed suprized to find my shafts painted when I had my bottom done a month ago. It caused them pause.

Wish you had the prop to help with forensics.

I'll watch this thread with interest.

Steve

[backman]

Shafts were new with the repower

1.5 years;612 hr's on them.

No vibrations prior to the snap; no prop strikes in the near past.

I am now wondering if I should be proactively pulling and replacing the other shaft at the same time.

[bktuna]

hey back man,
I am running a 28, with twin 250 cummins, yesterday was going out fishing for shark and before i could clear the inlet, rumble rumble... soo I am alittle concern pulling the boat today...

[Split Decision]

Larry

You have 600hrs on them already?

You better start thinking about a repower soon. Again.

You must live on that thing.

[bktuna]

Larry,

What power set up do you have?

[backman]

D4-260's, 1 1/2 shafts, 18 X 26 Acme props

The shafts were new with the repower last April; they too have 612 hours on them.

What's the big deal - I only have 235 so far this year; but figure I can get another 200 or so if I work at it a bit

Anyways - 400/year is good for them, right?

[code blue]

shafts

Boy it is hard to imagine those 1and 1/2 inch shafts snapping without some restriction on the props themselves! Was ther any damage to the hull or chips on the paint to make you suspect some type of debris involved? I take it the dripless seals held, was there any wear on the portion of the shaft left?

[backman]

Snap....

they are pulling the starboard to dye test that keyway and make sure there is not a flaw there also.

Nice; eh?

[Bullish]

I was going to start a new thread for this question but most of you could probably answer it rather easily.

My starboard side shaft has been making a slight grinding noise (not too obnoxious but noticeable) when I taxi out of my lagoon but once I power-up, I can't hear anything unusual. I figured that I should probably check the cutlass bearing. What is the easiest way to get to it? I assume there is no way to do it with the boat in the water.

Thanks in advance for the direction.

[backman]

Ask me tomorrow at 4

I'll be an expert after I spend an hour in the boatyard next to the hard top ornament

I know each winter I check the whole shaft; strut; alignment by

1 - making sure the prop turns freely and has no bind in the cutless bearing
2 - pushing and pulling on each rudder; strut, prop and making sure there is no motion

I also look for wear marks on the cutlass bearing and along the shaft both at the bearing and at the log.

Of course; based on results I am the wrong person to ask ;(

[backman]

Good news of sorts

First - insurance is a wonderful thing.
Second - 2 shafts and one prop are on their way.
Third - my forensics have established root cause. I have a 1' long gouge with orange paint in it at the starboard bow; just above the bototm chine. Green paint just above it.

Rope burn spiraling down the broken shaft; I hit a pot; dragged the rope into the shaft and snap....

It was not a manufacturing issue.

[Bullish]

I haven't logged on in a week. Thanks for the advice. I'll use your suggestions and take a closer look this Fall when I pull her.

[Fin Addict]

Strut Breaking

I was wondering if anyone ever heard of a strut breaking.