Replacing a Beneteau style prop nut anode

[robinwr]

Discovered that we had lost our Beneateau style prop nut anode so decided to replace it whilst giving the hull a scrub before we head to Bangor for the winter.

Having just done it I'm now wondering if replacing this underwater is a good idea. Given that the screw locates in the nut is there a means of the water in the nut escaping as the screw is tightened or is the water pressure developed by the tightening nut going to be a problem. The screw seemed to tighten without significant effort so I'm hoping that it will be ok.

Best case scenario - screw loosens again (although this time I did apply loctite)
Worst case scenario - pressure causes nut to split and prop falls off.

This is in my mind as advice is to remove all oil and/or water when replacing cylinder head bolts after a cylinder head gasket renewal. Maybe this is because heat will exacerbate the pressure?

All experience and knowledge appreciated.

 

[bobgoode]

Done it this way on several occasions and no problems as yet.

 

[Sailfree]

You may find that screw loosened by the anode corroding away beneath it. I had this on the Volvo Saildrive anode. I considered painting the surface in contact with the screws but found buying SS bolts with a Torq or Allen key head (instead of Philips type) enable me to tighten screws that little bit more and never lost another anode.

 

[robinwr]

Thanks for the comments. When we were out in May for antifouling I replaced both the shaft anode (using a MGDUFF with the stainless steel inserts) and the prop anode. The shaft anode is still there albeit looking a bit smaller than when it went on but the prop anode has disappeared, screw and all.

We did quite a bit of motoring this summer around the north of Ireland and the parts of the Clyde and we did have an incident in Campbeltown where the four bolts holding the propshaft to the gearbox prop shaft decided to come undone (thankfully after we had tied up to the pontoon). In the morning when we came to spring off and head to Stranraer we had no drive. There must have been an element of vibration in the shaft but I would be one for sensing unusual noise or vibration but detected nothing untoward. I can only assume that the cause of the shaft bolts loosening has had the same effect on the prop anode.
I didn't fill in the hole in the anode with filler and I didn't loctite the retaining screw.
I have added loctite to the screw (which is a flanged ss hex screw and which fits snugly in the anode) but I'm not sure how effective it will be given that I could only coat the screw and not both mating surfaces as directed on the packet.

When we're out next year I'll be doing a belt and braces job and use loctite and fillers.

I've pinged a mail to MGDUFF to get their view but thanks for the re-assurance bobgoode. I'll be checking it again once we get to Bangor.