Ellie Prop Shaft to universal Joint at motor

[Ian Fleming 1Participant @ianfleming1]

Fitting the stern tube & prop shaft and seek advice as to how to secure the 4 mm shaft to the universal joint. Do I require to include a nylock nut at the universal joint or is there a better way to prevent the shaft self tightening ?.

Looking forward to your kind advice

Ian

[Ian Fleming 1Participant @ianfleming1]

Lock nut Required?

[Bob Abell 2Participant @bobabell2]

Good Evening Mr Bond !………..Sorry, couldn`t resist it

I use a simple locknut to secure the Couplings and also the Prop

Use two spanners to achieve the locking action

Bob

[Ian Fleming 1Participant @ianfleming1]

Thank you Bob for your informative reply.

Without being disrespective at all ,I'm 71, and I think I might have been called that before once!

Ian

[ashley needhamParticipant @ashleyneedham69188]

Ian, Bob is of course spot on, but use a plain nut, not a nyloc, as you will want to adjust the shaft for minimum end-end play for water tightness and include a brass or better still, nylon washer between the locknut and propshaft bush would be best. Same for the outer end

​Nylon washers can be made using milk bottle plastic cartons and a hole punch. Yes, they are not ACTUALLY nylon but as good as and essentially free!. Proper Teflon or nylon washers are of course available.

​Ashley

[Ian Fleming 1Participant @ianfleming1]

Thank you Ashley will follow your additional advice

Ian

[Ian Fleming 1Participant @ianfleming1]

Can I further ask after installing the prop shaft as per your kind guidance should the prop shaft be free spinning or relatively stiff so to speak?

Without any innuendos intended my shaft (in my version of Ellie) is stiff and requires slight force to have it revolve ( now there's a thought!)

Ian

[Bob Abell 2Participant @bobabell2]

Hi Ian

I would give it a good greasing and spin it with an electric drill till you get complete satisfaction

Bob

[Ian Fleming 1Participant @ianfleming1]

Thanks again for the advice Bob much appreciated. It does presently seem to require too much effort to turn the shaft. I've tightened at the motor end of the shaft until I know it probably won't leak.

I've been able to test that as I've built Ellie using diagonal planking and have fibre glassed it internally. I was able to flood the model and test for leaks. So far none but I would have been surprised if it leaked , as I used to as a youngster lay up GRP boat moulds.

Ian

[Malcolm FraryParticipant @malcolmfrary95515]

When everything is lock nutted in place, nothing should bind. In use, the motor turns the prop, the pro pushes against the water, and the prop tries to go forward. This causes the face of the prop boss, with a bit of help from the thrust washer, to seal against the outer end of the shaft tube bearing as it starts pushing the rest of the boat along. Unlock the inner, move the coupler back a flat, re-lock. It should spin easily but with minimal end play. The oil/grease only needs to keep the water out when the bat is still, but you do need the inner lock nut and thrust washer to keep things under control in reverse.

[Ian Fleming 1Participant @ianfleming1]

Thank you for that detailed response Malcolm

Ian

[Ian Fleming 1Participant @ianfleming1]

Thank you for that detailed response Malcolm

Ian

[ashley needhamParticipant @ashleyneedham69188]

Ian. If in doubt…..remove the shaft, clean it and slide it back in the tube. It should revolve freely with no resistance (other that the bearing friction which will be minimal). If this is NOT the case and it is binding, then either the shaft is bent (check by rolling on a flat surface, glass for instance) OR there is something wrong with tube/bearings.

​If it is free, then you just need to slacken off the locknuts by a fraction. I always use plastic/nylon washers, and adjust the nuts so that there is zero free play. A smear of grease on assembly and drip of oil inboard is all I apply, the bottom bearing can be dripped but is effectively water lubricated. But as I have said in the past everyone has their own preference for lubrication.

​Ashley

[Ian Fleming 1Participant @ianfleming1]

Thanks again Ashley. You have found the problem I think. There is an unreasonable amount of resistance just putting the shaft in the tube.

I think the problem may be of my own making in that if you look at Page 73 of the prototype build, Paul recommends there that you file down a M4 nut to remove the flats and use it for a central "bearing" in the tube. I failed miserably to do this and filled nuts to their untimely death, perhaps the wall thickness of the brass tube is different from the one Paul used. However I was able to get the nylon inserts out of of two M4 nylock nuts and threaded them onto the prop shaft. I think they may be too tight a fit.

Don't really know if they are really necessary however at 20" long it seems a long stern tube without that support for the shaft.

Thank you all for your continued interest and help

Ian

[Paul TParticipant @pault84577]

Hello Ian

One of my favourite lubricants for a narrow bore shaft is Lanolin but for salt water I use 3in1 sewing machine oil. I only use grease in larger shafts with bores of 10mm and over.

The filed down nut is a cheap shortcut instead of using a proper bearing, it supports the shaft mid span and prevents 'whipping'. To file them down I lock a couple of nuts onto a 2in bolt and put the bolt into a drill……..hold the nuts against a file and pull the trigger…….quick and even filing.

Check the tightness of your nylon inserts by putting the shaft into the tube with a little light lubrication, the shaft should turn freely without using any force. If the nylon inserts are tight give them a light filing and they will soon fit.

I hope this helps

Paul

[Ian Fleming 1Participant @ianfleming1]

Thanks Paul,

Sounds like a cheap effective solution to a tricky problem when your hands are too big and clumsy!

I have filed down the nylon inserts and now they are at least letting light 3 in 1 oil slowly pass them, and are turning freely.

Paul can I please ask you another question. My local pond where Redcar Model Boat club meet is salt water and is immediately adjacent to the North sea.. My question is then,given I will never get flat calm conditions ,does Ellie need ballast if constructed using plywood as per Bob's prototype and sailing on an inshore pond?

My Ellie is a heavy construction using diagonal planking internally glass fibre covered. The deck is 3 mm ply being covered with 4 mm wide strip planking( courtesy of Mr Wetherspoon)

I am also using two 600 motors.

Kind regards

Ian

[Paul TParticipant @pault84577]

Hello Ian

The boat was designed to take about 50mm of 'chop' before having to think about ballast and yours with the twin motors and heavy construction will fair better than most.

Given your exposed sailing location a stiff cross wind might be a bigger factor especially if a gust gets under the wheelhouse roof.

I'm sorry to say that, given the potential wide range of conditions at Redcar, the eventual ballasting will be a case of trial and error.

You could consider using extra batteries as ballast (then you would benefit from extra run time)

Paul

[Ian Fleming 1Participant @ianfleming1]

Hi Paul,

Thank you again for the response.

50 mm of "chop" at Redcar boating lake has never been seen in my 15 years here.There are even days when the kids pleasure boats are not allowed to be used due to the waves. lol

I should have said and I trust it's not sacrosanct that due to the normal weather conditions here I decided that the wheel house hinged roof was a no go and have built a solid roof and will have sliding doors to the wheelhouse.

Fortunately I have doubled up on the batteries so that should be a bonus all round.

Thanks again

Ian

[Paul TParticipant @pault84577]

Hello Ian

Nothing is sacrosanct….its your boat and you can do whatever you like and hopefully you might improve the design.

Oddly enough Bob and I discussed having a fixed wheelhouse roof with sliding doors when we built the first Ellie and I even drew a few sections/elevations but the idea fell by the wayside so I am really glad that your version will include this feature.

I am looking forward to seeing the photos of your fixed roof and I'm certain that Bob will be looking in to add his expert opinion.

Paul

[ashley needhamParticipant @ashleyneedham69188]

It is not generally appreciated but very small "off the shelf" bushes and bearings, in bronze or plastic can be purchased for very small amounts of money, and used to make your own propshaft tubes, or whatever.

​As an alternative. A few seconds searching "small bushes and bearings" produces any number of suppliers.

​Dog drive prop adaptors are also available cheaply and these just grub-screw on a shaft, meaning that all you need is a bit of plain rod and you can make custom propshaft assemblies no trouble. X or S series plastic props can have the end cap filed off and a small slot filed in the base for the dog drive, a small file gets rid of the thread for a good fit over the shaft.

Just a thought.

​Ashley

[Ian Fleming 1Participant @ianfleming1]

Can I ask another question please?

How do you keep in place the "filed down nut" as in Paul's post above of the 19 July 17?

I have been test running my Ellie on the bench and noticed excessive vertical movement at the prop.

Removed the prop shafts to find the "filled down nuts" adjacent to the motor not where I positioned them at all. I had in fact 3 of these bearings on each shaft ,one in the middle and one at each end.Can you please give me some advice on this problem

Thanks again

Ian

[Bob Abell 2Participant @bobabell2]

Ian

It sounds to me, like you haven`t fitted any bushes at the ends of the prop shaft tube?

What have you used for the actual prop shaft?

Bob

[Dodgy Geezer 1Participant @dodgygeezer1]

Posted by ashley needham on 21/07/2017 08:28:01:

It is not generally appreciated but very small "off the shelf" bushes and bearings, in bronze or plastic can be purchased for very small amounts of money, and used to make your own propshaft tubes, or whatever.

​As an alternative. A few seconds searching "small bushes and bearings" produces any number of suppliers.

​Dog drive prop adaptors are also available cheaply and these just grub-screw on a shaft, meaning that all you need is a bit of plain rod and you can make custom propshaft assemblies no trouble. X or S series plastic props can have the end cap filed off and a small slot filed in the base for the dog drive, a small file gets rid of the thread for a good fit over the shaft.

Just a thought.

​Ashley

I make all my own prop-shafts and skegs on a small lathe, but that's not essential for bushes. You can make nylon bushes quite easily by drilling the appropriate hole in a small chunk of nylon, then putting a bolt through it and turning it using a power drill and a file.

[Paul TParticipant @pault84577]

Ian

My apologies as I should have added that the filed down nut should be locked in position.

There are a few methods of achieving this:

1/ Use a nylock nut for the filed down nut….(hint)…after filing you wont be able to use a spanner so run the nut into position with pliers)

2/ Use thread locking liquid.

3/ After it is in position deliberately damage the shaft thread either side of the filed nut, this a tad destructive and not a prescribed engineering solution but is nevertheless a very effective method of keeping the nut in the correct location.

4/ Use two filed nuts on each shaft and lock them together to prevent any migration.

Hope this helps but please let me know if you need further explanation on any of these points.

Paul

[Ian Fleming 1Participant @ianfleming1]

Firstly thank you Bob, Dodgy Geezer & Paul.

Bob I have brass bushes at both ends of the prop shaft. I used M4 threaded rod for the shaft and 8 mm o/d brass tube for the stern tube.

Dodgy Geezer thanks for your practical,cost effective advice. I had read Ashley's previous post and I think I'll order 5 mm bushes but try Paul's advice initially

Paul thanks for your advice/clarification which I'll now follow. I'm convinced that the turned down"locking nuts" will resolve the issue.

My only concern is that your advice is pure common sense which I am disturbed I don't possess enough of. I might gain some when I grow up but I've no intention of doing so!

Kind regards

Ian

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