72' by 6'10 etc etc

[Nine of Hearts]

Strange, but true, but absolutely my last word on it - argue on!!

 

Strange but false, I'm afraid. You can do a mathematical model to disprove it. For ease of figures, say we've got a top and bottom pound of 1000 litres, a lock the hold 100 litres at it's low point and requires 200 litres to fill. Along comes a boat that displaces 50 litres. Top pound holds 950 litres + boat, lock has 300 litres (it's conveniently been left full) and bottom has 1000. Boat enters lock, 50 litres leaves lock chamber into top pound as boat moves in. Top pound 1000 litres, lock 250 litres + boat, bottom pound 1000. We now lower the boat, draining 200 litres into the bottom pound. Top pound 1000 litres, lock 50 litres + boat, bottom pound 1200 litres. Out comes the boat, and 50 litres washes back into the vacated chamber. Top pound 1000 litres, lock 100 litres, bottom pound 1150 litres + boat. If you run that scenario with, say a 75 litre displacement boat, you'll find that you end up with 1125 litres + boat, which looks like you've used less water. You haven't, because the aggregate volume in the bottom pound is still 1200. So 200 went over the spillway in both cases, or the level was raised by the same amount. The next person to use that lock to descend is still going to have to use 200 litres from the top pound to fill it, no matter what quantity back-washed in after the previously departing boat.

[Timleech]

I'd heard that too, which is a bit annoying as the only type of charger socket I've never had trouble with is Nokia's jack pin type

 

I suppose it enables the makers to include other functions in the same socket, I've had Nokias with three dicrete sockets on the bottom.

 

Tim

[boatmoving]

Have to agree with Nine of Hearts. "Alan's falicy" arises because he only considers one half of the lock cycle. Over a full lock cycle, the water used is the same whatever size boats go through it.

[mykaskin]

The river was already navigable to Burton on Trent when the T&M was proposed. It's my guess that to capture the trade, the new canal had to be able to accept the craft of the Trent.

 

That was my understanding.

 

I also understand that the bridgewater's canal was made to take a Mersey Flat. The coal from his mine was transhipped before it's journey to Manchester, and yes they did sail the boats down the cut when the wind was favourable.

 

As been said, it is also my understanding that the (original) Harecastle tunnel and it's engineering challenges (read costs) meant a smaller dimension, and so it makes some sense to make them half the width of a flat (thereabouts) rounded to a nice 7 foot, with 6 inches to spare to get them into and out of the locks.

 

The locks at Hurleston have been collapsing for a very long time, and while I'm happy to be corrected, I suspect they were built to take 7 foot wide boats.

 

I think Joshers when built were normally built to the 7 foot guage as they had to travel across the country. When the Grand Union Canal company decided to build the Royalty Class boats, they were built to 6'11" persumabably because of the problems facing some canals, however after only a couple of years the Star Class boats went for a reduction in depth, and so to maximise carrying they were made a couple of inches wider and a good few inches longer as the Grand Junction was built with a nice bit of slack around the edges, ie. longer and wider than needed. This limited their range, but since the main traffic was along GUCCC's canals it didn't matter. I understand that FMC also made "oversize" craft, and many were Grand Union size/length (especially the Steamers?) but could usually squeeze into other locks like other GU craft can today.

 

Some boats, while on a narrow canal didn't have to pass through locks, and so the 'ampton's were born, maximising the existing dimensions on the Wolverhampton level of the BCN.

 

In later years - after nationalation BWB (DIWE?) designed some new boats which were 6 foot 10 inches wide to over come the lack of maintainance on the cut and this may be the source of the current dimensions used by modern narrowboat builders.

 

Of course, there have been other waterway dimensions originating from mostly sea and river going craft of the area - like on the Lee navigation, but Brindley wanted a "Grand Trunk" linking all the major rivers together, the Trent and Mersey was the first part of this plan.

 

Hope that helps.

 

Have to agree with Nine of Hearts. "Alan's falicy" arises because he only considers one half of the lock cycle. Over a full lock cycle, the water used is the same whatever size boats go through it.

 

However one boat carrying half the weight using the same amount of water as could be used by two boats is still a waste of water however you do the math.

 

Mike

Edited January 24, 2011 by mykaskin

[alan_fincher]

Have to agree with Nine of Hearts. "Alan's falicy" arises because he only considers one half of the lock cycle. Over a full lock cycle, the water used is the same whatever size boats go through it.

 

But I was careful to spell out what my scenario was.....

 

If you think of the whole operation of a boat going downhill through just one lock, including entering and leaving.....

 

Going the other way, or onwards through a series of locks, different things apply....

 

For the avoidance of doubt, overall, I think it makes bugger all difference, and is just an acadewmic argument in all practical terms.... but I stand by that one example I did give.

 

Mike is of course also right - the most effective way to use a broad lock is with 2 times 70 foot boats in them - anything else is in it's way wasting water. At one stage in it's history the Grand Union had a second narrow lock added alongside each existing double one, (Tring Summit to Stoke Hammond) - specifically so when narrow boats operated singly, rather than in pairs, only half the water need be used.....

[Nine of Hearts]

Mike is of course also right - the most effective way to use a broad lock is with 2 times 70 foot boats in them - anything else is in it's way wasting water. At one stage in it's history the Grand Union had a second narrow lock added alongside each existing double one, (Tring Summit to Stoke Hammond) - specifically so when narrow boats operated singly, rather than in pairs, only half the water need be used.....

 

When I use double locks on my own, I only raise one paddle. That way I only drain water from one side of the chamber.

[Pluto]

Canal boat, and hence lock, size was usually based on the local river or estuary boat then in use. In the north west, these were around 68 feet long and perhaps 15 feet wide, though the more up river boats were narrower. In the north east, around 60 feet was the standard length, with 14 feet being the width in the early eighteenth century. The Bridgewater was initially built for 68 feet long wide boats with a rudder length of up to four feet. The Worsley mine boats were initially similar in length, but half the width, though by the end of the eighteenth century there were at least six different sizes for the mine boats, depending upon how far into the mine they worked. 68 feet plus 4 feet or rudder gives 72 feet, and that is what was used for the T&MC, with the width being halved to reduce building costs. Over the years, some lock sides have moved slightly, so a boat 6 feet 10 inches wide should not have too much difficulty anywhere.

[the grinch]

When I use double locks on my own, I only raise one paddle. That way I only drain water from one side of the chamber.

 

thanks for that, it made me laugh!!

[RupertG]

I hear that the EU have decided that Micro-USB is to be the new standard for mobile phone chargers. It's relatively new so I don't think it has been fully taken up but I do know that HTC have changed from their proprietary (but compatible) mini-USB to micro.

 

Linky

 

And you may gaze upon the Micro-USB and say: it's not that much smaller than the Mini-USB, but even so will it not be more fragile and have a shorter insertion life, and be more difficult to use, especially for the older punter?

And the standards people will cough, and stare their shoes, and mumble:'could be, guv'.

And you may say: So what's the point of that, then? Why not just standardise on the existing, common, proven Mini-USB?

And they will say, if you push them: only way to get agreement was mandate something entirely new. That it was worse in every way for the consumer meant nothing compared to not letting the other guy getting a march on you. Sorry. Enjoy your new standard.

And they will run away.

[RLWP]

And you may gaze upon the Micro-USB and say: it's not that much smaller than the Mini-USB, but even so will it not be more fragile and have a shorter insertion life, and be more difficult to use, especially for the older punter?

And the standards people will cough, and stare their shoes, and mumble:'could be, guv'.

And you may say: So what's the point of that, then? Why not just standardise on the existing, common, proven Mini-USB?

And they will say, if you push them: only way to get agreement was mandate something entirely new. That it was worse in every way for the consumer meant nothing compared to not letting the other guy getting a march on you. Sorry. Enjoy your new standard.

And they will run away.

 

That's the nice thing about standards - there are so many to choose from

 

Richard

[steelaway]

The river was already navigable to Burton on Trent when the T&M was proposed. It's my guess that to capture the trade, the new canal had to be able to accept the craft of the Trent.

 

 

Hi

 

I am supprised by this, as there is 40ft plus rise in the river level between Derwent Mouth and Burton on Trent.

 

Alex

[mykaskin]

Hi

 

I am supprised by this, as there is 40ft plus rise in the river level between Derwent Mouth and Burton on Trent.

 

Alex

But there is probably a good few feet difference between the canal and the river level at Burton, and it's surprising just how much a bendy shallow river can raise while still allowing boat to travel.

 

http://www.jannel.co.uk/bondend_canal.htm

 

Mike

[steelaway]

But there is probably a good few feet difference between the canal and the river level at Burton, and it's surprising just how much a bendy shallow river can raise while still allowing boat to travel.

 

http://www.jannel.co...ndend_canal.htm

 

Mike

 

 

Hi

 

Thanks for that - a good read. I am very interested in canal history and now I realise the major significance of Shobnall Basin.

 

Alex

[twbm]

Canal boat, and hence lock, size was usually based on the local river or estuary boat then in use. In the north west, these were around 68 feet long and perhaps 15 feet wide, though the more up river boats were narrower. In the north east, around 60 feet was the standard length, with 14 feet being the width in the early eighteenth century. The Bridgewater was initially built for 68 feet long wide boats with a rudder length of up to four feet. The Worsley mine boats were initially similar in length, but half the width, though by the end of the eighteenth century there were at least six different sizes for the mine boats, depending upon how far into the mine they worked. 68 feet plus 4 feet or rudder gives 72 feet, and that is what was used for the T&MC, with the width being halved to reduce building costs. Over the years, some lock sides have moved slightly, so a boat 6 feet 10 inches wide should not have too much difficulty anywhere.

 

Thank you. Does Pluto still survive?

[Pluto]

Thank you. Does Pluto still survive?

No, vandals set fire to the hull at Ellesmere Port in the mid-1980s, which at least shamed the local authority into providing some security fencing at the Boat Museum. What upset me most was not the loss of the hull, several people here can tell you of the problems of maintaining an old wooden L&LC boat, which is much more difficult than maintaining a wooden narrow boat, but the cabin in Pluto was the last surviving one still as built and painted by a traditional boatyard. The paintwork was last done in the 1950s. Other surviving wooden L&LC boats had had their cabins removed to improve access for hull maintenance.

[Grebe]

Sorry to be late with this reply, but I had to dig in some papers to confirm the details.

 

 

The answer

Mr John Sparrow of the Trent and Mersey company wrote to five 'Brindley' canal companies asking them to send two representatives each to a meeting to be held in Lichfield on 14/12/1769 to discuss/confirm common standards. In theory they were already working to the same dimensions but this meeting formalized the narrow lock dimensions. Mr Brindley was tasked to survey all the workings to confirm 'standarisation'.

 

Apart from the T&M these were the Bridgewater canal, Staffs & Worcs canal, Oxford canal, Coventry canal and Birmingham canal. The Droitwich was not asked, it being a 'barge' canal to take Severn craft. The Chesterfield canal was still in its infancy and nor invited.

 

My thoughts

Even today boat design and dimensions are a compromise between numerous requirements. With a canal the only fixed dimension is the length, the width and depth are etermined by the vessels that will use it and the depth of the company's pockets to finance the digging. The wider and deeper you dig the more it will cost. Presumably they figured out that 25 tons could best be carried in a boat we now know as a full size narrowboat. In turn this gave a canal about 24 feet wide with a depth of about 3 feet. Economies came in tunnels where a smaller cross-section could be used. A doubling of beam to 14ft beam would need four time the volume of earth to be dug for a tunnel.

Edited January 26, 2011 by Grebe

[Pluto]

Sorry to be late with this reply, but I had to dig in some papers to confirm the details.

 

 

The answer

Mr John Sparrow of the Trent and Mersey company wrote to five 'Brindley' canal companies asking them to send two representatives each to a meeting to be held in Lichfield on 14/12/1769 to discuss/confirm common standards. In theory they were already working to the same dimensions but this meeting formalized the narrow lock dimensions. Mr Brindley was tasked to survey all the workings to confirm 'standarisation'.

 

Apart from the T&M these were the Staffs & Worcs canal, Oxford canal, Coventry canal and Birmingham canal. The Droitwich was not asked, it being a 'barge' canal to take Severn craft. The Chesterfield canal was still in its infancy and nor invited.

 

My thoughts

Even today boat design and dimensions are a compromise between numerous requirements. With a canal the only fixed dimension is the length, the width and depth are etermined by the vessels that will use it and the depth of the company's pockets to finance the digging. The wider and deeper you dig the more it will cost. Presumably they figured out that 25 tons could best be carried in a boat we now know as a full size narrowboat. In turn this gave a canal about 24 feet wide with a depth of about 3 feet. Economies came in tunnels where a smaller cross-section could be used. A doubling of beam to 14ft beam would need four time the volume of earth to be dug for a tunnel.

It's not quite as simple as this, although cost was a major factor as English canals were usually built with private money, rather than public. Other factors to be considered included water supply, though this would have been virtually the same for equal tonnages whether the locks were wide or narrow. One other important factor was what traffic was expected to be carried; wide boats were certainly able to carry larger individual packages, and was it better to have a wide boat such that cargoes could be delivered to coastal areas without transshipment. The Duke of Bridgewater was certainly in favour of a narrow T&MC as that ensured canal cargoes were transshipped between narrow boats and his flats for delivery to and from Liverpool. The extra cost of the transshipment could certainly make the additional cost of a wide canal more acceptable. The difference in cost between the two was certainly much less than the four times you quote, even for tunnel building, with Rennie's cost for a wide or narrow Rochdale Canal being £350,000 compared to £290,000.

[Grebe]

It's not quite as simple as this, although cost was a major factor as English canals were usually built with private money, rather than public. Other factors to be considered included water supply, though this would have been virtually the same for equal tonnages whether the locks were wide or narrow. One other important factor was what traffic was expected to be carried; wide boats were certainly able to carry larger individual packages, and was it better to have a wide boat such that cargoes could be delivered to coastal areas without transshipment. The Duke of Bridgewater was certainly in favour of a narrow T&MC as that ensured canal cargoes were transshipped between narrow boats and his flats for delivery to and from Liverpool. The extra cost of the transshipment could certainly make the additional cost of a wide canal more acceptable. The difference in cost between the two was certainly much less than the four times you quote, even for tunnel building, with Rennie's cost for a wide or narrow Rochdale Canal being £350,000 compared to £290,000.

 

What four times doubling in cost? Four time more earth to dig out for a tunnel was what I wrote.

[Iain_S]

What four times doubling in cost? Four time more earth to dig out for a tunnel was what I wrote.

 

But is it? If the bore is circular, or semi circular, then yes. However, if rectangular, and assuming the same depth (and I'm not suggesting building a tunnel like this, although Falkirk comes close ), then two times more earth removed would do it.

 

On a wide tunnel, the roof arch could be made shallower,which would cut down on the soil to be removed. However, wide tunnels would bring their own problems with stability, and the cost would probably end up at around four times that of a narrow tunnel?

 

Iain