Volvo propellers can fall off!!!!!!

Bav34

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We have a Volvo saildrive on our boat.

For the uninitiated, the prop slides onto the shaft splines. Then a cone is spun on behind it and tightened by putting a screwdriver through two holes and giving it a heave with the gearbox in reverse and the prop locked with a length of wood between it and the floor. Then a bolt is put through the cone into the shaft and tightened.

I fitted it after changing the anode last April. I KNOW how much effort I put in tightening everything. A lot! Also since then we have motored probably 500 miles which has the effect of continuing the ‘tightening’ process.

However!

We were in The Morbihan. Basically rocks and very strong currents. We had moored on a buoy by Larmor-Baden. The fridge didn’t seem to keeping the food cold so I had to keep it on which was obviously draining the service battery.

To keep it charged I ran the engine for an hour a day and thereby lays the problem.

I have read for many years that you shouldn’t run a diesel for too long without a load on it. Something to do with glazing the bores???

Being on a buoy I couldn’t run ahead so I put it in reverse. Porquoi-pas? Never heard of props falling off!!! A couple of days later we cast off to go up to Vannes. Engaged gear. NOTHING! Luckily drifted onto another yacht and some passing fishy people took a line back to ‘our’ buoy.

Cutting a long story short we found a diver who not only recovered the prop. but also the very expensive cutter AND the cone ….even a plastic washer that sits between them!!! Couldn’t believe our luck. Opal in the UK had the cone kit but not the right size prop.

The only bit he couldn’t find was the bolt but after several celebratory whiskies with him and his son he nipped under the boat and fitted it all as I was adamant that the cone would hold it all together as long as I didn’t go in reverse. Made it to La Crouesty where he had arranged for a bolt to be available. What a guy!! All he wanted was 80 euros and I gave him the bottle of scotch for putting on the prop.

Anyway, although all ends well I think that you should be warned about the prop problem. It was on tight. The bolt had loctite on it. The engine was only just in gear …. not running fast. A p*ss poor bit of design as far as I am concerned. I totally accept that you don’t see hundreds of saildrive yachts floating around propless so the problem is limited I guess to the amount of time that you actually run it in reverse.

Hope this helps someone avoid the same problem. Twas a bit tense at times when the tide hit 4 knots on our buoy and I’m thinking that I might actually have to sail off to hit the mandatory rock!

Now just have to find out how to re-gas the fridge!!
 
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So it's not just the keels, then.

[/ QUOTE ]What? Are Volvo and Bavaria one and the same?
 
"I fitted it after changing the anode last April. I KNOW how much effort I put in tightening everything. A lot! "

There is a torque figure given for tightening this nut. Overtightening risks stripping the thread on the bolt.
 
Done it loads of times without a problem. The two different thread pitches make it difficult for it to fall off... I suspect over tightening. I use a 6" allan key for the central screw and tighten against my hand holding the prop. Been fine so far (touch wood!!!)
 
I take my prop off every year and have put it back with no problems. I just hold the prop and tighten the cone with a large screwdriver through the holes on the cone. The bolt in the end seems to jam the threads together which seems to inhibit the cone from moving - I tighten this up with an allen key fitting driven from my small socket set to make sure it is tight. I use plenty of grease but wipe it off the threads.
 
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Done it loads of times without a problem. The two different thread pitches make it difficult for it to fall off... I suspect over tightening. I use a 6" allan key for the central screw and tighten against my hand holding the prop. Been fine so far (touch wood!!!)

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I had two fall off - both factory fitted - both before the anodes had needed replacing. No problems in last 3 years though.
 
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