Staircase Locks

[Drayke]

Staircase Locks, if a boat has just come down, so locks are empty, were does a boat going up draw water from to fill locks, do you have to run water from top pound?

[Wanderer Vagabond]

Yes!

[churchward]

All things being normal then no you should not have to do that.  The bottom lock you enter to go up still has a lower water level than the next lock. When you equalise you should be able to get over the lock cill into the next chamber.  A lot of staircase locks have side chambers or ponds anyway where extra water can be drawn from to get you up.

Sometimes though there may not be enough water and so you would have to recharge the locks above from the top pound. We got stuck like that at Grindley one time. The bottom and middle locks were equalised and gates opened but there was not enough depth to get the skeg of our boat over the cill so we had to send more water down from above.

[john6767]

3 minutes ago, churchward said:

All things being normal then no you should not have to do that.  The bottom lock you enter to go up still has a lower water level than the next lock. When you equalise you should be able to get over the lock cill into the next chamber.  A lot of staircase locks have side chambers or ponds anyway where extra water can be drawn from to get you up.

Sometimes though there may not be enough water and so you would have to recharge the locks above from the top pound. We got stuck like that at Grindley one time. The bottom and middle locks were equalised and gates opened but there was not enough depth to get the skeg of our boat over the cill so we had to send more water down from above.

Ignoring Watford and Foxton which work differently do many staircases have working side ponds, Hanbury does I know, but I would have thought in the case outlined you would want all locks full except the bottom. Of course you can run water down as you go rather that filling them all to start with, but the effect is surely the same and what is needed.

[Wanderer Vagabond]

9 minutes ago, churchward said:

All things being normal then no you should not have to do that.  The bottom lock you enter to go up still has a lower water level than the next lock. When you equalise you should be able to get over the lock cill into the next chamber.  A lot of staircase locks have side chambers or ponds anyway where extra water can be drawn from to get you up.

Sometimes though there may not be enough water and so you would have to recharge the locks above from the top pound. We got stuck like that at Grindley one time. The bottom and middle locks were equalised and gates opened but there was not enough depth to get the skeg of our boat over the cill so we had to send more water down from above.

Taking a typical staircase lock, Chester as an example, for a boat to go up from the bottom all locks, except the bottom lock, have to be full. If you try to go up otherwise you wont get over the cill into the next lock up (ask me how I know)

[churchward]

6 minutes ago, john6767 said:

Ignoring Watford and Foxton which work differently do many staircases have working side ponds, Hanbury does I know, but I would have thought in the case outlined you would want all locks full except the bottom. Of course you can run water down as you go rather that filling them all to start with, but the effect is surely the same and what is needed.

Not necessarily of course there are many different designs. However, as I said even with the bottom lock empty after a boat has come down the nest lock up etc. will have a water level higher than the bottom lock and enough to fill the bottom lock again sufficiently for the boat to get over the cill. However, also as I said you can have to send water down from the top pound as well it just depends on the design of the locks and how much the gates leak I guess so the levels get too low to sufficiently fill the lower chamber. If like Watford and Foxton you have side chambers or ponds you fill from them too.

Edited April 16, 2017 by churchward

[churchward]

5 minutes ago, Wanderer Vagabond said:

Taking a typical staircase lock, Chester as an example, for a boat to go up from the bottom all locks, except the bottom lock, have to be full. If you try to go up otherwise you wont get over the cill into the next lock up (ask me how I know)

Indeed! we had much the same issue at Grindley once and even with the lockies in attendance operating the flight for us there was not sufficient water in the nest chamber to get us over the cill. But thankfully quickly sorted by sending a little more water down.

[john6767]

8 minutes ago, churchward said:

Not neceserily of course there are many different designs. However, as I said even with the bottom lock empty after a boat has come down the nest loxk up etc. will have a water level higher than the bottom lock and enough to fill the bottom lock again sufficiently for the boat to get over the cill.

I can't see how that would work.  Let's say each lock when full has 10ft of water and when empty it has 5ft, then with the bottom and next "empty" they each have 5ft of water in them, if you fill the bottom from the next it will fill it only half full, i.e. To 7ft 6in, and the next lock would only have 2ft 6in in it.  True that may possibly be enough, but then do the save again from the next lock up, and no chance.

Edited April 16, 2017 by john6767

[churchward]

4 minutes ago, john6767 said:

I can't see how that would work.  Let's say each lock when full has 10ft of water and when empty it has 5ft, then with the bottom and next "empty" they each have 5ft of water in them, if you fill the bottom from the next it will fill it only half full, i.e. To 7ft 6in, and the next lock would only have 2ft 6in in it.  True that may possibly be enough, but then do the save again from the next lock up, and no chance.

I know I was being a naughty tease!

Folk can see here an article about staircase locks.

http://www.jim-shead.com/waterways/Articles.php?wpage=13

[BruceinSanity]

8 hours ago, churchward said:

I know I was being a naughty tease!

Folk can see here an article about staircase locks.

http://www.jim-shead.com/waterways/Articles.php?wpage=13

So let me see if I've understood you correctly. You were deliberately giving a novice bad information about how to work a typical staircase lock?

If so, what a thoroughly unpleasant thing to do!

[NickF]

I always work it out that in a "proper" staircase without side ponds then every lock needs to be set against you apart from the first one.

[magpie patrick]

As a rule of thumb when going up all the locks must be full except the bottom one, when going down all empty except the top one. As most (but by no means all) staircases are two rises this is easy to figure out. If you need to fill the locks the water comes from the top, if you need to empty them it goes out the bottom. 

There are instances when the middle cill  is low enough, or the residual water in the upper chamber deep enough, that you don't have to follow this rule. Most of us (me included) won't know the idiosyncrasies of any particular staircase so stick to the basic rule. 

People get confused as one of the most famous staircase locks at Foxton is different, but Foxton (And Watfordon the same canal) are the exception not the rule.

I think the new Gatun locks on the Panama canal have a similar system to Foxton, but I'm not likely to get there any time soon! 

[Ex Brummie]

Even if there is sufficient water in an 'empty' top lock to pass the cill, by the time you have then filled up to get out of the top lock by the same amount of water as if you had filled it to start with, so why not do it to start with and save the hassle of having to try and fill a bottom lock from the top to release a boat from the cill?

[nebulae]

Bratch(which is not a staircase,but is an oddity) and Grindley Brook(which is very busy) both have clear instructions on  how to use. No instructions on the new concrete lock on the Droitwhich narrow,Bingley 3 and 5 rise always had a keeper when I used them. Staircase at the beginning of the Caldon has instructions? CaRT policy on clear sighn how to use unmanned locks seems a bit random?

[Ex Brummie]

Just down from Bratch on the S&W is Botterham, which has clear instructions. Bratch is 3 individual locks without a pound you can pass in between them. The general instructions for a staircase are, for going up or down, empty bottom and full top. If going down, then there is often a weir to take any overflow if the bottom lock is full. As I said earlier, whilst some staircases may fill from a empty top, sufficient to pass the cill, if you start with a full lock, you will never be in a situation where your boat may be halfway in, and you then have to fill a double length, which could present a safety issue.

[Scholar Gypsy]

2 hours ago, Ex Brummie said:

Just down from Bratch on the S&W is Botterham, which has clear instructions. Bratch is 3 individual locks without a pound you can pass in between them. The general instructions for a staircase are, for going up or down, empty bottom and full top. If going down, then there is often a weir to take any overflow if the bottom lock is full. As I said earlier, whilst some staircases may fill from a empty top, sufficient to pass the cill, if you start with a full lock, you will never be in a situation where your boat may be halfway in, and you then have to fill a double length, which could present a safety issue.

Good point. Boats can sink if they get stuck on the cill half way in or out of a lock, and the water level then drops (eg a leaking gate) before you can get to the right paddle to put some more water in. This happened on the Huddersfield Narrow a year or two ago.

[churchward]

13 hours ago, BruceinSanity said:

So let me see if I've understood you correctly. You were deliberately giving a novice bad information about how to work a typical staircase lock?

If so, what a thoroughly unpleasant thing to do!

Oh dear had a sense of humour failure today?

[Drayke]

Thanks to all, now I understand. Hopefully.

Fred

Edited April 17, 2017 by F DRAYKE

[Mike Jordan]

There is a simple rule to remember with conventional staircase locks - first one in your favour and all the rest against you.

[sharpness]

6 hours ago, Ex Brummie said:

Just down from Bratch on the S&W is Botterham, which has clear instructions  Bratch is 3 individual locks without a pound you can pass in between them.

You cant pass in The Bratch, although they are actually 3 individual locks rather than a true staircase, the pounds between the locks are only a few, less than 10, feet long.

Steve

 

[Tacet]

14 hours ago, Scholar Gypsy said:

Good point. Boats can sink if they get stuck on the cill half way in or out of a lock, and the water level then drops (eg a leaking gate) before you can get to the right paddle to put some more water in. This happened on the Huddersfield Narrow a year or two ago.

It more problematical.  If the flat-bottomed boat is on the sill and tight against the lcok sides, the water has no easy route past the boat to raise the stern.  Refilling/flooding the pound from above could just raise the bow and thus speed up the sinking.

 

 

[Tacet]

11 hours ago, Mike Jordan said:

There is a simple rule to remember with conventional staircase locks - first one in your favour and all the rest against you.

True.  But if the rest are in the opposite state to the first lock, they are are not really against you - they are for you.