Things to check on shaft drives

[syd]

I'm having my Berty lifted out in a few weeks time, delayed by arctic conditions. I would like your advice on things to check and how to check them. i.e. Rudders, shafts, bearings etc. I've only ever had stern drives before, so the shaft drive configeration is new ground. Last time it was lifted I was unable to be there .

Regards

Syd

 

[Tranona]

Anodes, play in the cutless bearings in the p brackets and play in rudder bearings. Cleaning and inspection of props and checking security of nuts.

 

[omega2]

Grab a hold of the props and shake them up and down and side to side if you can hear noise at the P bracket then they are in need of replacing, same with the rudders fore and aft this time any play should be investigated. I take it you know what an anode looks like? it's the lump of new unpainted metal photo 1, and they will very likely need replacing depending on how long they have been there, if they look untouched then there is something very amiss, i.e. the bonding wires are broken/loose connections. Props generally only need cleaning and "ringing" hit them with a hammer (not hard) if they ring they will be fine if they sound dead then you could have problems. Still on props, check that they are snug on the shafts i.e. no float, check the locking tabs/split pins and nuts any slackness could be due to the woodruff key worn or even not there.

Yours may look like photo 1, photo 2 shows me ready to replace the cutless and photo 3 almost shows the woodruff key (very faintly), note the two crub screws in the P bracket they have to come out so that the cutless will drift out. Generally allen screws and sometimes have to drilled out and re tapped.

 

[Neil_Y]

I'd say measure the clearance between bearings and shaft, as a guide for a (2") 50.80mm shaft, (2 3/4") 69.85 Carrier you are looking at 0.20mm new (MRD min radial displacement) and you should be looking at changing when this gets to 1.27mm. You can usually measure the gap at the top of the shaft and this is the Radial displacement. Once past 1.00mm they wear much quicker and will give extra noise/vibration. We expect bearings on working boats in abrasive water to last around 2 years. The clearance differs depending on the shaft size and wall thickness of the bearing.

I wouldn't advocate drifting bearings out as P brackets can be bent out of true, use a press/puller if they are pressed in bearings, consider epoxy clearance fit bearings if you have to change as they come out by heating the carrier, no press or drift needed. If they are rubber bearings they will probably have been press in.

If you are doing this DIY you can use clearance fit bearings to check P bracket alignment by chocking shaft and having a dry run installation of bearings, they should slide on the shaft and into the carrier and turn easily.

Rudder bearings will run similar clearances if they are water or greased plain bushes.

 

[Bandit]

Check the props are on good antight and that the prop and prop nut are not going "pink" which is a sign of corrosion. Check bonding.

If you have spurs or stripper rope cutters replace the bearing on an annual basis.