Flexofold failure

[nkrats59sailor]

The FoF propeller of my 2017 Jeanneau SO 449 just fell off without any warning. We left the mooring field under power, set sails, cut the engine, set throttle on revers and sail for less than an hour when wind suddenly died. Fired up the engine, shifted forward and there it was - no propulsion. Tried revers - same thing. Made it back to the club, called a diver thinking something wrapped around the prop but when he came out, shock came out too: there is no propeller, bare shaft was the only thing he could see. 

Our engine is Yanmar 4JH57 equipped with sail drive SD60-5 and 440 hrs on the hourmeter.

Now what?

[Charlie-Bravo]

“Now what”

It seems likely that someone forgot to tighten the nut and engage a tab washer or pin . The prop nut doesn’t actually hold the prop on, it just secures it from loss should the taper on the shaft ‘let go’, which evidently it did. 

Also there is a distinct possibility that the shaft taper or prop taper didn’t match, or was contaminated with dirt or too much grease on assembly, a properly machined and fitted prop can be jolly difficult to get off without the correct puller.

So now , unless you know where your prop is, and can dive to retrieve it, a new prop you will purchase, I wouldn’t think a new FoF is any more likely to fall off than any other prop once correctly fitted, but perhaps it’s a chance to try something else ………… any recommendations anyone?

CB

[Don Reaves]

Jul 13, 2023 3:14:47 GMT nkrats59sailor said:

The FoF propeller of my 2017 Jeanneau SO 449 just fell off without any warning. We left the mooring field under power, set sails, cut the engine, set throttle on revers and sail for less than an hour when wind suddenly died. Fired up the engine, shifted forward and there it was - no propulsion. Tried revers - same thing. Made it back to the club, called a diver thinking something wrapped around the prop but when he came out, shock came out too: there is no propeller, bare shaft was the only thing he could see. 

Our engine is Yanmar 4JH57 equipped with sail drive SD60-5 and 440 hrs on the hourmeter.

Now what?

Welcome to the forum! I'm sorry to hear of your misfortune, and I agree with CB that it's time for a new prop. Depending on the bottom, it can be very difficult to find a lost item even when you know where it went down. Since you could have dropped it anywhere, I would assume it's gone for good.

[j24sailor]

Jul 13, 2023 9:01:24 GMT Charlie-Bravo said:

“Now what”

It seems likely that someone forgot to tighten the nut and engage a tab washer or pin . The prop nut doesn’t actually hold the prop on, it just secures it from loss should the taper on the shaft ‘let go’, which evidently it did. 

Also there is a distinct possibility that the shaft taper or prop taper didn’t match, or was contaminated with dirt or too much grease on assembly, a properly machined and fitted prop can be jolly difficult to get off without the correct puller.

So now , unless you know where your prop is, and can dive to retrieve it, a new prop you will purchase, I wouldn’t think a new FoF is any more likely to fall off than any other prop once correctly fitted, but perhaps it’s a chance to try something else ………… any recommendations anyone?

CB

I agree it is probably the fault of the installer so you may have some recourse there. James