Forums, Engine, Gearbox, Stern Gear, etc, Rudder bottom bracket screws loose

GlennG at 09/04/2012 00:16:00
When I lifted Perle this year the bottom rudder bracket (is it called a ‘pintile’?) was loose. I chopped off the skeg foot and found that the aft-most screw was loose and has no ‘grip’ in the GRP, e.g. it keeps turning when you screw it in.

What’s the consensus for fixing this?

I hear that there’s little hard resin to drill a significantly deeper hole. An engineer has suggested drilling a 1" hole transversely through the skeg and inserting a 1" rod that’s been drilled and tapped to take the pintile screw. Sounds OK to me and would permanently solve the problem. Opinions?

Simon Begley at 09/04/2012 19:32:04
When we replaced Blue Jalma’s rudder we also replaced the bottom bracket. The old one was rather worn and had suffered some galvanic corrosion. The holes in the new bracket didn’t match the old ones. JR advised filling the holes with a hard epoxy filler and drilling and tapping new holes into this. Two years later everything is still solid.

waratah912 at 09/04/2012 22:27:30
We had a similar problem with Waratah about 10 years ago. All the screw holes were filled with Epoxy and then re-drilled and tapped. Screws refitted with loctite and no problems so far.
If you’ve got the rudder out, consider replacing the rudder bearings too.

GlennG at 10/04/2012 09:36:40
Such a pity that you can’t turn the boat over so you can pour in the epoxy:-)

The bracket and rudder appear to be in good condition as are the screws. The main issue is the aft-most screw — which takes all the load — being loose. I do wonder if filling, drilling and tapping it will work adequately as re-tapping will remove pretty much all of the new epoxy.

I do quite like the idea of inserting a drilled and tapped bar transversely through the skeg. Then I know that the thing won’t work free as the load is spread across a large area. Has anyone had any experience of this?

Regarding the rudder bearings; isn’t this an awfully difficult job to press out the old bearings? Not least accessing the cavity.

George Isted at 10/04/2012 10:11:36
Here is another idea that would be worth considering, I have done this elsewhere on the boat. Get a pair of nuts for the machine screw, drill out the hole in the skeg so that it is big enough to accept the full length and width of the maching screw AND nuts. Epoxy the nuts and machine screw in place having applied a SMALL AMOUNT of Vaseline (or grease/release agent) to the screw threads only. Once set you can remove the machine screw and you are ready to go – no cutting of threads into GRP required. Hope the above makes sense.

GlennG at 11/04/2012 22:04:22
That’s a good idea. It could be further re-enforced by drilling diagonally and inserting screws set in epoxy.

Looking at the bracket, the aft-most screw will take a real pounding from the constant sideways forces whilst helming and (considerable) weight of the rudder. I’m surprised that this bolt isn’t much longer.

waratah912 at 12/04/2012 22:43:54
No need to turn the boat upside down, mix the epoxy with Microfibres to a consistency like peanut butter and it stays put. Isn’t the weight of the rudder is taken on the top bearing rather than the heel fitting?
Also consider using a stainless helix insert which will bite deeper than a normal machine screw, but is threaded internally to accept a machine screw. for example http://www.wti-fasteners.co.uk/ This requires a smaller hole than drilling out to accept a nut and provides a longer threaded length.
As regards rudder bearings, the old ones are plastic so can be cut (judicously!) with a hacksaw blade to release them. Fitting the new bronze ones is rather more fun – definitely a tight fit and consequently no downward load on the heel!!

GlennG at 03/05/2012 06:00:57
The engineer who’s done the work to replace the prop shaft, install a PSS and cutlass bearing said that one reason for the pintile bearing becoming loose was because of the additional weight placed upon it because the spacer/washer above the top bearing has worn. He’s fitted another spacer which has lifted the rudder up a little, thus reducing the weight on the pintile.

Seems logical. Anyone else found this?

St Paddy at 08/05/2012 08:06:31
You will have a job to keep the epoxy in, the hole will be wet and drity. If your heel plate is standard it will be held by 5/16 whit. counter sunk screws.

I would retap the holes if it were mine or a customers boat.

Your next size up from that is M10 with a tapping drill of 8.5mm (5/16 is 8mm) so you can clean out your worn hold and re-tap. You could go 3/8th UNC

you need the heel plate holes opened out I would use 316 socket Cap heads. GTC fixings will post them to you google them, no min order. The chandlery will only have 405 stainless, that will only last a few years in the heel plate. when done post the tools back.
Use acetone to clean and sikaflex when you assemble, the side load on the heel plate skids the fitting side to side and that is why the screws and threads fail. If that happens you have a blade rudder with a 1 1/4 shaft.

St Paddy at 08/05/2012 08:08:09
I agree the rudder should be suspended not sitting on the heel plate. There should be a delrin thrust washer machined to suit. I’m happy to post one if you tell me how thick it should be

michaelforrest at 30/04/2013 14:19:44
Hi, sorry to re-ignite this post but I have exactly the problem descirbed and wondered what was done as the final solution to the problem. The boat is in Italy and im heading back in June and want to make sure I have everything I might need with me.

Many thanks

Michael

St Paddy at 30/04/2013 15:13:13
Hi Michael
Hope the pump handle was ok.
The best fix is to open out the holes to the next screw size, They were originally 5/16 whitworth. I would open them to M10 and clean everything up and sikaflex the plate on and use new M10 socket cap head screws. Try to keep the screws clean. You will need to open the holes in the plate to clear the screws.
Have you cut of the cover yet, If not just use a hack saw. you can see the line of the plate, cut onto it you can then feel the blade hit the stainless plate, this gives you have a clean cut and easy to refit, inch tape and epoxy. If you want to discuss this phone me on 07764 188815

George Isted at 30/04/2013 16:20:55
Hi St Paddy, I’m pretty sure that most/all of the weight of my rudder is sitting on the heel plate, if I understand your email correctly you suggest putting a delrin washer between the top bearing of the rudder shaft and the block at the top (so the block is sharing the weight with the heel fitting).

St Paddy at 30/04/2013 17:11:11

non of the weight should be on the heel plate. All should be taken by the Bronze block on top.
On older boats this was a fabricated stainless block, but still the same design.
If the rudder sits on the heel plate then the laminate and lay-up is wearing away on the stainless plate.
I have fitted a delryn thrust washer between the bronze block and the stainless flange of the rudder tube.
I might have machined some of the bronze off to get the heights right, I can’t remember. I can remember having it up in the lathe. I think you will have space for a thrust washer if only a thin one.
I think the stock is 1 1/4 and the block might be 2 inch or a bit bigger, I can check. You will need a imperial socket to undo the centre bolt in the block. I can tell you the size later when I check mine. remember to take it out with you, I can machine you a selection pack and post it, if you like.

michaelforrest at 30/04/2013 18:46:17
Hi Robin (St Paddy)

The pump was excellent thanks a million for that

About the rudder, I thought id carry on the discussion on here as it may help others in the future. I’ve never tapped a hole in my life, for tapping epoxy do i use a steel hand tap? Any tips on where to buy one. I could probably borrow one from the yard in Italy but they charge for everything and will just moan about me doing the work etc. so i’d rather just do it myself.

I’m guessing i might need to ask them to open up the existing holes in the heel plate though.

The rudder was replaced by the previous owner in 2007 but I don’t think the bottom bracket was changed at the time. I’m waiting for a reply to my email to confirm this but it’s perhaps time this was changed too (1979 boat) Do you know what the hole sizes are in the new brackets sold by Jeremy Rogers? It will be easier for me to take out the new plate withe the bigger holes in it as long as it’s a like for like swap.

So many people with this problem maybe should do a technical paper on this alone.

Thanks as always

Michael

George Isted at 01/05/2013 09:46:25
Hi Robin (St Paddy), thanks for the offer, what you have said makes complete sense and I had noticed a small amount of wear so it deserves some attention. I’m probably going to take the rudder off next winter so that the cutlass bearing can be replaced so I’ll drop you a note nearer the time if that’s ok, I’ll need to measurer the gap between top bearing and the bronze block. Thanks again.

moongirl at 02/05/2013 20:07:56
I have posted on this subject before! Whilst buying s/s bolts @ CP Fastenings in Southsea I spotted s/s helicoil inserts & thought they might be the answer to poor set screw fixings in the GRP part of the Skeg. Having a large ribbed surface it would seem that gluing them in with epoxy would give a very strong base for the screws.