Paddington Basin- Camden- St. Pancras Lock
Grand Union Canal
4 miles, 3 locks, 1 tunnellette
The morning didn't get off to a great start; we recieved a phone call at 8am from Amy's mum, telling her that Scrappy, her cat, had been hit by a car and was seriously hurt, to the extent that he would have to be put to sleep. This was a great shock and very upsetting, for both of us but of course for Amy especially.
We put our minds to happier things by cruising through Little Venice, and seeing it together in daylight, before heading down the Regent's Canal, intending to wind at Battlebridge Basin by King's Cross and either spend the night there or return to Paddington. This stretch of the canal was again familiar to us, as we've walked it several times, dreaming of having a boat; and, finally, that ambition was achieved. It helped lift our spirits a bit, but Scrappy's accident put a black pall over the whole day.
We moored on the short-stay moorings by Camden and looked around the market, enjoying some hot, fresh doughnuts, before visiting the local Halifax to reclaim bank charges (£100 back between us, rather nice really!) and then heading back to the boat. Warrior had, in the meantime, passed us whilst we were out, as we later found out, heading back from the Lee and Stort towards Uxbridge.
We moved off and descended the locks in fine style, impressing several gongoozlers and enjoying the attention of a community boat full of children- "Do you live on that boat? What's it like?" "Erm... awesome, thanks!"
And then, coming into St. Pancras lock, the day got even worse. The propshaft came loose AGAIN, very annoyingly.
It turns out that the most crucial grub screw, in the deepest hole, had sheared. Not wanting to continue on two grub screws, we moored up in desperation on the lock landing stage, leaving a note in the window to apologise and explain the circumstances, and then phoned around local DIY and hardware shops. One helpfully pointed us in the direction of Clerkenwell Screws, a shop selling nothing but nuts, bolts and screws; they had some high tensile M10 grub screws in stock- only these ones had more of a point, to ensure a better fixing, and they were twice as long for a better hold.
We raced over as quickly as we could, and just managed to get in and buy some before they closed. Once back on the boat, we found out that the sheared-off grub screw wasn't in the prop shaft, but was instead stuck between the flexible coupling and the oil seal; however, no amount of chiseling, hammering, levering, sawing, prodding or poking- or indeed swearing!- got it out. The only way to do the job properly, we reasoned, was to move the engine forwards to free it; and so we did. This time, as we knew what to do, it took about 15 minutes to move it. The grub screw came out easily, but after three attempts at getting the engine back and realigned, we gave up as it was getting too dark to see easily; the one 30w bulb in the engine room was insufficient, and we were too tired, upset and hungry for the precise task; we'll deal with it first thing in the morning.
There are a number of options on fixing the prop shaft properly. The best way, we've decided, is to replace the cone inside the flexible coupling so that it will properly attach onto the shaft- as it is designed to do!- rather than rely on grub screws. At the moment, the end of the prop shaft is too worn to do this adequately, so the solution may well be to cut the worn inch off the end and pull the prop slightly closer to the stern tube. However, more advice will be taken before we attempt anything so drastic. Anyone with experience of cutting and working with solid stainless steel is welcome to get in touch and offer advice! This is, we think, the permanent solution and it's how prop shafts are meant to be fitted; grub screws just don't work adequately, as we've found out!
So, all in all, rather a trying day.
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Did you get our email before about getting in touch? Steve says he'd need to see it, but even perhaps talking to him may be a help. If you are going to be where you are for a while we could speed up to try and get there if there's a possibility we could help. We'd still be a good two weeks getting there though. Give us a ring.
ReplyDeleteIf you need to machine the end of the prop-shaft, you will probably need to remove it from the boat, which means coming out of the water (unless you're _very_ brave!) In that case bear in mind that the boat-crade/slipway at Bill Fen is much cheaper than craning: the prices are on the website. If you talk to John Shotbolt in advance he may be able to organise the machining too. Of course this implies making it up the GU and down the Nene first. I don't know how possible that is.....
ReplyDeleteMP
We were thinking just the same - that it would be good to go to Bill Fen and get it out of the water. Loads of people there who would be keen to help (some more productively than others) and John himself of course with his wealth of experience and workshop full of parts. We're staying in Little Venice today, leaving for Uxbridge tomorrow morning, so if you need picking up let us know before tonight; otherwise we'll see you in Uxbridge at the weekend...
ReplyDeleteNever fear Moominpapa, Warrior will get the Duck there somehow!
Does your propshaft have a thrust bearing? In case you don't know, spinning the prop pushes (or pulls, in reverse) the prop and shaft. There has to be some way to transfer that force to the rest of the boat.
ReplyDeleteIn installations with solid propshafts (ie no coupling) the force is transfered to the back of the gearbox, and there is a thrust bearing there. I know that at least some sorts of flexible couplings don't cope with thrust, and there has to be a separate thrust bearing bolted to the hull and to the prop shaft between the prop and the coupling.
If your coupling is that sort, and the bearing has been omitted, that could explain everything: going into reverse is pulling the prop-shaft out of the fixings in the coupling which are intended to transmit rotation, but not pushing and pulling forces.
So, it's worth looking and checking to see if your coupling needs a thrust block: something like this:
https://simplybearings.co.uk/shop/i/ucp_200.jpg
At the moment, there's an oil seal which, whilst it isn't being used to seal the shaft, is I think acting as a bearing of some sort, as it's securely bolted to the sides of the swim. However, the prop moves in and out if it's levered (with a mooring pin in one of the holes) which suggests that there isn't a flange or anything bolted to the shaft to transmit the forces.
ReplyDeleteThe coupling itself is, I think, a Flexidrive (I think that's the brand name) with a big spun aluminium housing and a brass cone inside it.
Jim suggested a possible fix- my uncle has offered to machine us a new propshaft, so we could have it extra long and bolt it directly to the gearbox, dispensing with the flexible coupling for now until we can afford a new one, or get the old one apart and fit it.
At the moment, the coupling is bodged with the grub screws; three little ones to transmit 40 h.p. or so just isn't working. They will hopefully hold until we can get to Bill Fen, where we can attend to it properly and make a proper repair.
BTW, we're hoping to be in Uxbridge on Sunday with Jim and Sarah, so perhaps we'll see you there!
The coupling and oil seal, btw, are visible here:
ReplyDeletehttp://3.bp.blogspot.com/_FXLjgqnOPag/SLRnccrnIBI/AAAAAAAAAYM/LHk_sYgbLCI/s400/24082008928.jpg
James said: "At the moment, there's an oil seal which, whilst it isn't being used to seal the shaft, is I think acting as a bearing of some sort, as it's securely bolted to the sides of the swim. However, the prop moves in and out if it's levered (with a mooring pin in one of the holes) which suggests that there isn't a flange or anything bolted to the shaft to transmit the forces."
ReplyDeleteThis is the slightly rusty thing on the left, yes? It's difficult to see, but that could be a thrust bearing. If the it is, and the shaft moves freely through it, that may well be the problem. What's breaking your grubscrews is not the rotational forces, its the propeller pulling the whole boat backwards using those screws. Can you look very carefully at the "oil seal" and see if theres any way to lock an inner, rotating part to the shaft.
It might be better to take this to email: simon@thekelleys.org.uk