How to remove this

[Romany 162]

This is the business end of a prop shaft on a Townson 36.

I decided amongst all the other things to do that the cutlass bearing housing needed removal and probably resealing - mostly cos fibreglassing outside is generally frowned on in the pissing rain but also it looked dodgy.

So i tried and wouldnt ya know it - the lower stud broke off . Original fitting, 48 years old finally succumbed to the ravages of time.

So i have drill it out and set a new one in but before I can, have to remove the housing. I've never done that, so - does anybody have advice as to how? It seems secure - like the sealant that remains is still effective which makes me wish I'd not touched it  😠

[LBD 128]

Firstly.. what  make of boat is is... others may have the same experience.

Then, is the stud made of SS or bronze?

When the studs are out or below the bearing housing the the housing usually screws off the stern tube.... how ever there are many variations on this theme so it would be good to find someone with experience particular to your boats arrangement.

What is on the inside by the gland and is it easy to get to?... If threaded, you may be able to  remove the gland, un-thread that end, and pull the stern bearing and tube out together. 

 

 

[Romany 162]

Townson 36.

Bronze studs i think.

Come to think of it - the last time this was done, I paid Bill to do it (10 or 15 years ago i think) i recall a thread on lower end of the tube so I'll try and unscrew the upper stud rather than backing off what i thought was a locking nut. Of course with the stud still in the housing cannot be unscrewed.

[LBD 128]

See how you go... on my boat the studs on the out board end are to position the bearing inline with the dead wood,  the stud on the inboard end is just for locking to stop the assembly unscrewing from the tube.  Clamping force is the threaded tube between the two ends.

I must have made close to a 50 stern tubes over the years... some times one end is silver soldered on, and on a couple of occasions I have seen the tube and bearing a one piece casting.... but threaded both ends is by far the most common configuration.

[Romany 162]

Ok Thanks. Assuming we have a tube, threaded at both inboard and outboard ends would one end be LH thread and the other RH?

[LBD 128]

No, both threads will be conventional, right hand.... think of a piece of threaded rod.....

Other wise.... one end will undo while the other does up... consider a turn buckle.

 

[waikiore 399]

Yes that is a standard cutless housing, should be threaded on to a copper stern tube, of course the lag screws will have to be wound out to allow removal.

[ricka 3]

I cant see why you would remove it. It looks like a timber boat in which case everything is wet in that area anyway

 

[waikiore 399]

Because it is a lot easier to replace the cutless bearing with it on the bench and not having to let go the shaft and draw it, which can often  be a problem (clearing the skeg for example) Multi skin Townson yachts are not always wet down there if they have been glassed. Yes I have worked on one or two...  

[ricka 3]

2 hours ago, waikiore said:

Because it is a lot easier to replace the cutless bearing with it on the bench and not having to let go the shaft and draw it, which can often  be a problem (clearing the skeg for example) Multi skin Townson yachts are not always wet down there if they have been glassed. Yes I have worked on one or two...  

Oh yer the skeg.

[Romany 162]

Mostly i wanted to make sure it is sealed, however as soon as i broke the first of the 2 screws it became a necessity anyway.

And - as we seem to have assembled a bevy of knowledable ones- i have on many occasions looked at my old school stuffing box with less than complimentary sentiment.

If i were to pull the tube for purpose of checking that its all good but also intending to go to dripless system what issues might i encounter and can you walk me through it? Note - No requirement to be in 100 words or less

 

[Oldlog 11]

Go to chatfields in Glenfield 

100% it was supplied by them back in the 70’s. I had the same issue on my townson and they had bolts etc off the shelf to sort it all. Could explain exactly how it was fitted etc etc. 

also looked into fitting drip less box. Henley will do a threaded adaptor that fits the existing box and it should fit the keel floor spacing. Really easy. I put modern Teflon infused stuffing in and it is cold and basically dry so haven’t bothered going on with it. 
 

replaced the bearing with “Thorlon”. Carefully cut the old one and pull him out. Take the inner dia of the bearing housing in a few spots and the shaft dia.  Chatfields make it up and you press it in 

Easy
 

[Oldlog 11]

No matter what you trying to achieve you have to remove those lag bolts….they will be threaded into a bronze block within the keel Timbers. 
mine broke too….. get a set of “easy outs” from Bunnings and put a soldering iron on the bold for quite a while and they will come out

[Romany 162]

Thanks all..

[shedman 10]

Just a note of caution re going to a dripless seal:  whilst the stuffing box is technically not a support bearing it does give the shaft a bit more support than many of the dripless seals.  My old man replaced the stuffing box on his Townson with a dripless seal and thereafter had a hell of a problem with harmonics in the shaft.  At some rpm the shaft would whip so much that it banged against the tube - sounded like the proverbial two skelletons wrestling inside a 44 gallon drum!  Lots of things come into play including type of prop, engine power, rpm range etc, but  just go into the exercise with your eyes wide open that the propellor shaft is pretty long on the Townsons so you might find that changing to a dripless seal might require other changes to the drive line support.  'Ain't nothin' simple with old boats!

[Romany 162]

Funny. I've always thought that Des' placement of the iron sail led to a relatively short shaft, but when u think about - u could be right. I appreciate the cautionary tale.

 

[waikiore 399]

Yes the shafts -particularly on the 34's and 36's are quite long, Chatfield do make a replacement seal for the admiralty pattern gland that you will have -which contains a support bearing and a hose tail to take the seal which then can float on the shaft -this is the right way to go if you are keeping the copper stern tube -and if you have the room in front of the where the existing gland was to fit it all.

Otherwise you can fit a glass stern tube as I have to four Townson yachts , be careful of where the keel bolts are when boring to get to clean timber, these have the advantage of never catching electrolysis and you can fit the stern bearing straight in and the forward (intermediate) bearings where it suits you -thus stopping any shaft whip . The seal then fits over the forward end of the tube. The Tube is of course epoxy and glued in permanently with epoxy and sized to take standard cutless bearings for your shaft, not some odd bit of glass tube that I have seen some playing with here! For example for 1" shafting the standard sizes are 1" ID x 1 1/4" OD x4" long therefore your tube must be 1 1/4" ID x 1 3/4" OD and whatever length is required  . This is a permanent fix and you can then have a sweet running shaft and dry bilge.

 

 

[Romany 162]

So today I got the housing removed, both lag screws broke off so drilled out. Lag screws were defintely 'rotten' - quite crimson where they sheared.

Undoing housing off the tube was easy - nice and firmly attached by courtesy of some sealant but wound off easily when the big stilsons came out.

Hopefully Simon at Chatfields is going to agree the housing isnt rooted. $600 for a new one not in my budget atm.

The query for you all though is when i refit, do i wipe out old grease to make sure i get any swarf,  then pump new grease in as well as apply sealant around the mating faces and lag screws?

[waikiore 399]

No grease, just sealant behind the bearing housing -and a small amount on the threads.

[Romany 162]

Now Im ready to reinstall the housing and have to drill out the holes in housing to accomodate 7/16th lagscrews.

Would 3/8 holes in deadwood be ok for the screw to 'bite' or is that too tight?

And what thread sealant should i i apply to the thread? Teflon based as I understand it is best but I cant find any.