Metalastik coupling, large GU motors?

[pete harrison]

Hi Tim ,yes it was that I was on about,Iam currently on the hunt for more suitable ballast that I can put under the back cabin floor and in front of the engine.It needs to be neat to stash,dense and not heavier than I can lift on my own.I can lift quite big bits of metal if I need to.Yours looks handy for hiding out of the way but at the moment I rely on the blue plastic drums full of water to put weight in the hold.

Hi George,look foreward to catching up with you sometime.Good Luck with Sandbach

 

When I bought BADSEY in 1988 high density metal ballast was stashed under the cabin floor in a similar way to FULBOURNE's. It was all rusty, oily and stunk so I quite hapilly removed it all (except for a couple of kerbstones right at the bottom that were too awkward to reach). I replaced this weight with five blue plastic drums filled with water. I felt these looked tidy as three fitted across the hold directly under the back end beams leaving only one on each side visable. I have always considered the beauty of using water in drums as ballast is that they can be easily emptied or moved when the boat becomes stuck on something. I appreciate blue plastic drums are not very 'traditional' but when the boats were in trade there would have been no need for ballast with the back end of the motors hold being full of personal possessions, coal for the cabin fires, tanks full of diesel and perhaps a little water in the bilge. If I were to buy another boat plastic drums would be amongst the first things on my list.

[madcat]

Got the drums but had to weigh the front down a bit to cope with Burton bridge and windy days.I not short of stuff in the cabin and engine room,once took 3 crammed full escort vans full of stuff out so Ian could renew the bottom under the back cabin and engine room.There were in the counter 3 huge lumps of cast iron that were just to heavy to handle and these were removed by 2 men with planks and patience and went to ballast a new boat.Its replacing this weight that Im working on.There is some metal ballast under the floor,all clean painted and sitting on those rubber scraper mats that have holes in.This has been a good plan with minimal condensation and nothing moved when going up the slipway at Hawne basin. I also keep under the floor dry and reasonably clean,usually dusty I admit .Also there are about 7 holes drilled in the triangular bit of floor behind the coal box and this seems to contribute to a good airflow and keeps it fairly well aired. Really its the compromise of mooching about in an empty boat.

Sometimes when it all gets too much I go and hide down the allotment but the ballast crop failed last year so its Plan B or C or ..........

[AMModels]

There is a type of container used on farms and in some industries which I would think would look good in the hold of an unconverted motor or butty, they are approx 1m cubed and encased in mesh with large bore taps to enable swift emptying or filling. They are called Light Duty Intermediate Bulk Container and they are seen here on this website Ive seen em in a few boats and they look the part imo...I have no connection to this company or any other btw.

[pete harrison]

There is a type of container used on farms and in some industries which I would think would look good in the hold of an unconverted motor or butty, they are approx 1m cubed and encased in mesh with large bore taps to enable swift emptying or filling. They are called Light Duty Intermediate Bulk Container and they are seen here on this website Ive seen em in a few boats and they look the part imo...I have no connection to this company or any other btw.

 

I use these at work and they probably would look O.K. in a motor (I don't know why you would want ballast in an empty butty). The beauty of the drums is that they can be manhandled to re-distribute their weight, whereas you need a fork lift truck to move an I.B.C..

[furnessvale]

There is a type of container used on farms and in some industries which I would think would look good in the hold of an unconverted motor or butty, they are approx 1m cubed and encased in mesh with large bore taps to enable swift emptying or filling. They are called Light Duty Intermediate Bulk Container and they are seen here on this website Ive seen em in a few boats and they look the part imo...I have no connection to this company or any other btw.

 

IBCs are OK but why go for "light duty" when a secondhand heavy duty one would be more robust?

 

In Alton I used standard steel 45 gallon drums which looked the part more than modern blue plastic ones. I had 13 in the hold but crucially they were on their sides so I could roll them about to alter the trim. Normally all 13 were at the back of the hold giving a very impressive bow position. Harecastle tunnel required 8 to be rolled forwards to the back of the mast. On leaving the tunnel 5 could return to the back leaving 3 forwards until after the low bridges at Stoke.

 

If they needed emptying I simply removed the bungs and used a bilge pump to keep the hold bilge emptying.

 

George ex nb Alton retired

[Tim Lewis]

Thank you Tim, I have to admit I have just taken the thing for granted but maybe now... How did yours fail,just broke one day or were external forces invoved like a biggish bit of wood getting jammed in the prop?

Will have to be getting sorted on the spares front.

 

The first one, as shown in the Facebook pictures, did not fail completely, we noticed the crack just before we were about to take the boat onto the Thames Tideway - we didn't go! Whilst we were waiting for the replacement we bolted straight through the coupling so bypassing the protection of the neoprene.

 

The second one went, as you guessed, happened when the stern rope wrapped around the prop. We think that this also weakened the coupling at the rear of the gear box which went a few months later - another story!

 

Tim

[PeterScott]

The first one, as shown in the Facebook pictures,

... entitled "Tim Lewis's Photos - Coupling" (Goshxxxx)

... happened when the stern rope wrapped around the prop.

... there were extenuating circumstances, btw, along the lines of recapturing the boat floating mid-canal after a vandal attack, then single-handing in the dark to a safe mooring (etc)

[madcat]

Thanks for the reply Tim, failure 2 sounds like one of those nights going by the further explanation from PeterScott.Any way I have set Boris [my hubby] the task of trying to find spare coupling rubbers. Halltherm parts online only seem to list 6 1/2" diameter in 3 grades of stiffness which is too small but Im sure another industrial user would need the bigger size.As soon as we find anything usefull I will post the details . Tim hopefully we will meet up at some waterways do,with a bit of luck at "beer O clock" .

Ballast,those big tanks are too heavy and cumbersome for me to get in and out of the boat on my own.Blue drums I can easily deal with,I too empty them into the hold and pump the water over the side with the hold bilge pump as George describes.

Those big tanks are great for rain water collection and storage,think I would favour the black ones for that because of algee growing in the white ones but wouldnt be too fussy if they were free.None have appeared down the allotments yet but should I find one floating in Gosty hill tunnel you will hear all about it,edited for swear words of course!!!!!!!

Edited October 13, 2009 by madcat

[Tim Lewis]

Thanks for the reply Tim, failure 2 sounds like one of those nights going by the further explanation from PeterScott.Any way I have set Boris [my hubby] the task of trying to find spare coupling rubbers.

 

<Snip>

 

As mentioned before we bought ours from Robush

 

http://www.robush.co.uk/product.cfm

 

Tim

[Chris Pink]

As mentioned before we bought ours from Robush

 

http://www.robush.co.uk/product.cfm

 

Tim

 

2nd row down 2nd from the left

[madcat]

At the moment I think Boris is just trying to find who makes the things,I gave him Robush phone no and it will have vanished into the rats nest which passes as his office!! While I have been away the whole thing has become out of sight and out of mind but now the cat is back and on the case.Of course if I bust mine the whole thing will move up a gear to panic mode.

Thankyou Tim for the information and Chris for reminding me,I will now rattle Boris's cage.

[Timleech]

This is what I believe to be a reasonably original setup:-

 

 

 

 

It had been run badly out of line, and with the Metalastik disc missing, the result being both half-couplings on the intermediate shaft had loosened, & needed bushing & new keyways and the shaft skimmed, plus replacement secondhand disc courtesy of Steve Priest. The intermediate shaft arrangement is a bit flimsy, but on the other hand that does perhaps limit the strain on the Metalastik disc because of the inherent flexibility of the setup, to some degree the shafting can 'flex to fit'. With the Fulbourne arrangement, with bearings either side of the flexible disc, while it's better engineered the relative alignment of the two shafts will be much more critical to save putting the disc under constant strain.

The foreward end of the shaft is rigidly coupled to the gearbox, so the engine has to be aligned such that the two flanges for the Metalastik are coincident with one another while the the gearbox coupling is bolted up, though the disc will cope with some angular misalignment.

 

I'm not a theoretical Mech Eng, but I suspect that it's no coincidence that bits of intermediate shaft either side of the support bearing have relative lengths of 1:1.4, or 1:sqrt2, I have a feeling that's a good ratio for preventing resonance etc. OTOH I may be talking drivel

Edited October 22, 2009 by Timleech

[Derek R.]

Looking at that set up, it would seem to me to be ripe for creating some whip between the gearbox output and the metalastic, which, because of its rotating mass, might induce an eccentric orbiting motion, in turn inducing wear in the stern tube. More support needed - the flexibility of the compound of the metalastic might be adding to the problem. However, I don't know the working rpm of the output. Even so, it doesn't look a happy bunny to me.

 

This isn't the unit that failed though, is it?

 

Maybe I'm over estimating it's ability to 'bend'. (Strange deja-vu moment there). It looks very much as Tycho was, and that had stern tube wear problems.

 

Derek

[Timleech]

Looking at that set up, it would seem to me to be ripe for creating some whip between the gearbox output and the metalastic, which, because of its rotating mass, might induce an eccentric orbiting motion, in turn inducing wear in the stern tube. More support needed - the flexibility of the compound of the metalastic might be adding to the problem. However, I don't know the working rpm of the output. Even so, it doesn't look a happy bunny to me.

 

This isn't the unit that failed though, is it?

 

Maybe I'm over estimating it's ability to 'bend'. (Strange deja-vu moment there). It looks very much as Tycho was, and that had stern tube wear problems.

Derek

 

As I said, it is so far as I know pretty much 'as designed' for the large GU motor boats, which are all now over 70 years old so it can't be that bad

Yes it will potentially put strain on the sterngear, probably not as bad as 95% of modern narrowboats with their short shafts, R&D couplings and flexibly mounted engines.

As I also said, I reckon the position of the support bearing isn't accidental, it's where it is to minimise whip or resonance.

 

Edited to add - isn't any 70+ year old boat likely to have sterngear wear problems?

 

Tim

Edited October 22, 2009 by Timleech

[madcat]

Tims photo is just as Halsalls set up and that survived the gravel runs,Boris always considered it a respectable set up once he got everything nicely aligned.

Waiting to hear from Robush who are just stockists so will still be trying to find out who manufactures.

As it happens Tim is one of the people whose opinion on matters engineering and boats that Boris and I value.He has been a great help to us over a number of years and helped us out a number of times

Edited October 22, 2009 by madcat

[Derek R.]

As I said, it is so far as I know pretty much 'as designed' for the large GU motor boats, which are all now over 70 years old so it can't be that bad

Yes it will potentially put strain on the sterngear, probably not as bad as 95% of modern narrowboats with their short shafts, R&D couplings and flexibly mounted engines.

As I also said, I reckon the position of the support bearing isn't accidental, it's where it is to minimise whip or resonance.

 

Edited to add - isn't any 70+ year old boat likely to have sterngear wear problems?

 

Tim

 

Well that's right. Daft to make judgments on a photo, and I suppose it was made a bit tongue in cheek.

From what I was led to believe, Tycho had it's stern tube bearing replaced more recently. But I have no hard evidence that it was so.

 

Having a shaft bearing support half way along and mounted to a hefty bracket fixed to the bottom plates can bring alignment problems when on dock. A lot depends on the placing of bostocks, and the shape of the bottom (Tycho's not flat). Afloat there should be perfect alignment, but on dock the bottom was pushed up (bed'ole wouldn't close), consequently the shafting was under pressure. Any adjustments made under those circumstances would be put out when refloated, and the engine had been out prior to '99 - on dock or not I do not know.

 

But as Tim says, they have lasted seventy years, and much of that in work, so can't be bad at all.

 

Modernboats - built for convenience of the owner's lifestyle. Nissan Micra's and 1930's Sunbeams - I know which I'd rather own and work on!

 

Derek

[Timleech]

Well that's right. Daft to make judgments on a photo, and I suppose it was made a bit tongue in cheek.

 

 

Having a shaft bearing support half way along and mounted to a hefty bracket fixed to the bottom plates can bring alignment problems when on dock. A lot depends on the placing of bostocks, and the shape of the bottom (Tycho's not flat). Afloat there should be perfect alignment, but on dock the bottom was pushed up (bed'ole wouldn't close), consequently the shafting was under pressure. Any adjustments made under those circumstances would be put out when refloated, and the engine had been out prior to '99 - on dock or not I do not know.

 

Derek

 

 

First rule of engine/prop shaft alignment - always do it with the boat afloat

 

Tim

[madcat]

I've been fishing for this thread and having dug it out I've revived it .

 

Boris never managed to get anywhere with sourcing spares for Halsalls coupling. I don't know why exactly.

 

Does anybody have a the origional drive shaft for a big Northwich lying unused that they might part with?

 

Are there any couplings that would work as a direct replacement for the Metallastic one ?

[Laurence Hogg]

Shelley Transmissions in Wolverhampton may be able to help.

[archie57]

I have some GU boat metallastic couplings if you are stuck for one......

[madcat]

Anybody got the shaft that runs from the reduction box to the coupling. Think it's 21/4 inches diameter for the big Northwich.

 

We spent a fair bit of time and lots of care lining Halsalls engine up after the new bottom under the back cabin and engine room had been done and the boat was floating again.

 

 

 

Selling my soul to the devil might have been a lesser commitment than allowing a big Northwich to take over my life

[larkshall]

Tim, could you photo the original preferably in situ. I'm sure I've seen something similar in our truck mechanics sheds

Oops you have since added piccies

 

What's the shaft diameters?

 

I know we're I have seen that arrangement, cotton mills the shaft works which distribute power around.

Edited August 19, 2015 by larkshall

[junior]

 

 

Selling my soul to the devil might have been a lesser commitment than allowing a big Northwich to take over my life

ANOTHER Big Northwich!

[hughc]

When we re-engined Banstead with a PJ3 we used a Cardan shaft made up with two largish Centaflex couplings. We could not find a new Metalastic insert. The set up worked really well and was quiet with no discernable "skipping rope" problems. Regards, HughC.

[madcat]

Is there life without a big a Northwich.

 

HughC your set up sounds interesting. Any chance of posting some photos on here .