My prop fell off... f.ck f.ck f.ck.

[model 10]

Originally Posted by fstbttms

Thin one (jam nut) first, big one (king nut) second.

Excellent. Walking through boatyards more seem to be wrong than right.

[hoppy]

Originally Posted by hoppy

Ahhh, so that's how it works. My washer was used with the prop before I fitted the flexofold and I think was perfectly flat with no sign of ever been previously being bent.

Correction, looking at the photo in hindsight it is obvious as to where it was bent



Now bending that whilst on the underwater rollercoaster might have been a challenge.

[fstbttms]

Originally Posted by hoppy

Now bending that whilst on the underwater rollercoaster might have been a challenge.

It's something of a challenge no matter where you do it. And by "challenge" I mean, "pain in the ass."

[hoppy]

Originally Posted by fstbttms

It's something of a challenge no matter where you do it. And by "challenge" I mean, "pain in the ass."

I wonder if filing down the inside edge of the washer would at least make it easier to get a screwdriver in. I suppose a chisel would perhaps make it easier?

When you need to hammer away UW, do you need a much heavier hammer than you need topside?

[hoppy]

Something I was thinking. If I had detected the problem before the Flexofold dropped. To fix it I would have had to take the blades off to get to the nut. And to get them off I'd have to needed to clear out the growth inside the bolts so I could use the hex keys. Then I would have needed the loctite 243 or spare bolts with the loctite already on them.

I don't have the loctite 243 and I don't have a spare shaft nut locking screw. So maybe it did me a favour falling off when it did because aside from the hassle of getting a key, I think putting the old prop on was a much easier job

I have ordered a full set of screws including two shaft nut locking screws so I'll have one spare.

[fstbttms]

Originally Posted by hoppy

I wonder if filing down the inside edge of the washer would at least make it easier to get a screwdriver in.

More trouble than it's worth, IMHO.

Originally Posted by hoppy

When you need to hammer away UW, do you need a much heavier hammer than you need topside?

No.

[hoppy]

Originally Posted by hoppy

Something I was thinking. If I had detected the problem before the Flexofold dropped. To fix it I would have had to take the blades off to get to the nut. And to get them off I'd have to needed to clear out the growth inside the bolts so I could use the hex keys. Then I would have needed the loctite 243 or spare bolts with the loctite already on them.

I don't have the loctite 243 and I don't have a spare shaft nut locking screw. So maybe it did me a favour falling off when it did because aside from the hassle of getting a key, I think putting the old prop on was a much easier job

I have ordered a full set of screws including two shaft nut locking screws so I'll have one spare.

I mean loctite 248

[carstenb]

Hoppy

Since i have the same set-up as you. You wondered if the tranny should be in reverse. Both Yanmar and Jeanneau (on Yanmar engines) note that the tranny should never be put in reverse while sailing. Even with a fixed prop, you should let it freewheel.

The source for this information is my Yanmar technical manual and my Jeanneau owners manual.

[hoppy]

Originally Posted by carstenb

Hoppy

Since i have the same set-up as you. You wondered if the tranny should be in reverse. Both Yanmar and Jeanneau (on Yanmar engines) note that the tranny should never be put in reverse while sailing. Even with a fixed prop, you should let it freewheel.

The source for this information is my Yanmar technical manual and my Jeanneau owners manual.

I recall a thread about this and I remember seeing a definitive answer, which I may or may not have seen in the manual myself, but I was also unsure what the answer was as I forgot . Given my nervousness of my replacement, I still think not having the prop spinning mad me feel more comfortable that the nut wasn't being vibrated loose.

I've tracked down the correct key in Stockholm, so I'll be getting a few and hoping only one of them will ever be needed

[Snowpetrel]

On keys. The engineering company that machined a new shaft for me a few years ago put a hole right through the key at one end and tapped it. The idea being if it jambed in the keyway it could be jacked out with a bolt with a matching thread. Not sure if getting the key out is an Issue with smaller props but it seemed like a smart idea.

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[hoppy]

Originally Posted by Snowpetrel

On keys. The engineering company that machined a new shaft for me a few years ago put a hole right through the key at one end and tapped it. The idea being if it jambed in the keyway it could be jacked out with a bolt with a matching thread. Not sure if getting the key out is an Issue with smaller props but it seemed like a smart idea.

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If mine was jammed in it would have saved me from having to run around yesterday


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[Snowpetrel]

Ha, very true... They made mine a very tight fit, had to tap it in gently. Haven't had to take the prop off again so no idea if it's going to be difficult.

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[Wotname]

FWIW, lapping a bronze prop onto a SS shaft using valve grinding paste is pretty easy and pretty quick. Assuming both have the "same" taper with an initial fit on around 25%, getting a 80+ % fit can be obtained in about 15 minutes of hand lapping. An SS prop is a different story

And with a 90+% fit the propnut doesn't need any locknut or cotter pin if you only use ahead . The torque is taken 100% in the taper and the prop force is always tightening the taper. Of course the propnut is still required for the times you are going astern and so it should be locked with a tab, jamnut , loctite or cotter pin.

[Snowpetrel]

As I recall the big ships props don't even have keyways, they use a hydraulic expansion system to lock the prop onto the tapered shaft, they don't seem to loose to many props! Saves the stress riser of the keyway in the shaft. The system is reversed to drive the prop off. Just a fun factoid!

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[beneteau-500]

Hoppy just caught this thread. One thing for shore once you request a tow in Greece they will impound your yacht you must hand over all yacht papers etc supposedly the repair must be done by a qualified engineer and then certified by a loyds registered surveyor this happens to me ie blown head casket the cost to me by the surveyor was 1000 euros another British yacht broke prop shaft the next day after my failure and cost him the same amount