Found locknut in engine bilge - 3YM30 Yanmar

[EmeraldCoastSailor]

My boat was thrown around quite a bit in Michael's 150 mph winds but she hung on for dear life and survived. As I was inspecting everything I found a loose lock nut that is the same exact size and type as the nuts on the shaft coupling, but they are all there and tight. What are the odds it was dropped during boat build 10 years ago? I can't see anything missing so I am at a loss as to where the lock nut came from.

Any ideas?

[Sir_Crabs_A_Lot]

Do this: examine the nylon ring for thread deformation. If there's none, it was never used, so toss it in the bolt bin.

[gamayun]

Yanmar nuts are stamped with a certain number because of heat (aggh, someone with the technical words will correct me on this) and so a regular lock nut (plastic inside, right?) probably didn't come off the engine. I think you're good especially if you checked all the threaded bolts carefully.

[Uncle Bob]

Originally Posted by gamayun

Yanmar nuts are stamped with a certain number because of heat (aggh, someone with the technical words will correct me on this) and so a regular lock nut (plastic inside, right?) probably didn't come off the engine. I think you're good especially if you checked all the threaded bolts carefully.

Originally Posted by EmeraldCoastSailor

My boat was thrown around quite a bit in Michael's 150 mph winds but she hung on for dear life and survived. As I was inspecting everything I found a loose lock nut that is the same exact size and type as the nuts on the shaft coupling, but they are all there and tight. What are the odds it was dropped during boat build 10 years ago? I can't see anything missing so I am at a loss as to where the lock nut came from.

Any ideas?

Ahh, shaft coupling bolts are not supplied by engine manufacturer but by the fitter. My bet would be a dropped nut on install and far easier to grab a new one than to stuff around looking for it in the bilge.

[dakno]

I would much like to know where your boat was during the storm? Ours is on Pensacola beach and it was looking grim up to 4 hours prior to landfall.

[EmeraldCoastSailor]

I anchored in Watson's Bayou on east side of Panama City. I had 150 mph sustained winds and was within 10 if not 5 miles of eyewall. I used 4 anchors in total but my main strategy was a tandem anchor rig with a total of 160' of chain and 4 nylon connections to the boat. The tandem anchors dragged perhaps 250' but eventually held. Amazing destruction all around including 100s of boats but mine was one of the very few that were floating clear when I found her the day after the storm. Very lucky!