Hiting gates

[mykaskin]

From a BW stoppage notice:

 

Significant boat impact damage has caused the cill to become cracked and loose, resulting in a potential hazard to navigation. Localised dewatering is required to enable BW staff to take measurements in order to fabricate a new cill. The navigation will be closed from 7am to 11am to facilitate this.

Boaters are requested to be cautious when approaching the bottom gates.

 

Now I've accidentally hit gates for a variety of reasons - mostly by forgetting how long it takes for the engine to build up speed - but how has the bottom gate cill got damaged in this case?

 

If hit from below the gates will open then shut again from the water pressure, and from above I wouldn't have thought enough shock would be transferred to the bottom, but mostly dissipated through the quoins.

 

Cheers,

 

Mike

[the grinch]

unfortunately the damage can be quite severe, if one gate slams faster than the other it will force the retaining pins which in turn allow the quoin to move, then the gates don't shut properly and put more pressure on the frame.

[Matthew Dowson]

Try driving fast into the lock going uphill, don't slow down, just allow the cill to be your brake - that's how its done.

[Naughty Cal]

Try driving fast into the lock going uphill, don't slow down, just allow the cill to be your brake - that's how its done.

 

Only if you are offering your boat for the experiment

[Tam & Di]

QUOTE

Significant boat impact damage has caused the cill to become cracked and loose, resulting in a potential hazard to navigation. Localised dewatering is required to enable BW staff to take measurements in order to fabricate a new cill. The navigation will be closed from 7am to 11am to facilitate this.

Boaters are requested to be cautious when approaching the bottom gates.

 

 

Try driving fast into the lock going uphill, don't slow down, just allow the cill to be your brake - that's how its done.

 

 

I still can't for the life of me understand how boat impact can happen to the BOTTOM cill.

Edited August 7, 2009 by Tam & Di

[PhilR]

QUOTE

Significant boat impact damage has caused the cill to become cracked and loose, resulting in a potential hazard to navigation. Localised dewatering is required to enable BW staff to take measurements in order to fabricate a new cill. The navigation will be closed from 7am to 11am to facilitate this.

Boaters are requested to be cautious when approaching the bottom gates.

 

 

 

 

 

I still can't for the life of me understand how boat impact can happen to the BOTTOM cill.

 

 

Nor me. BUT, maybe we should read this in the context of it being a typical report from BW office staff?

 

They probably meant TOP CILLS when APPROACED from the BOTTOM gates (i.e travelling uphill).

[MartinClark]

I still can't for the life of me understand how boat impact can happen to the BOTTOM cill.

The notice doesn't say anything about a boat hitting the gate.

 

It is the bottom cill that is being talked about here, not the top cill. And the cill in question in one of the wooden blocks that the gate closes up against, not the big stone step at the top end of the lock chamber.

 

In all the cases of boats damaging cills that I have been aware of, the most usual cause is a boat passing over the cill when the water level is too low. Part of the boat's bottom hits the wooden cill blocks or even snags on it. When the wooden cills have been dislocated they no longer form a watertight(ish) seal with the bottom gate and it can become nearly impossible to fill the lock completely, as water rushes out under the bottom gate.

[Pluto]

The notice doesn't say anything about a boat hitting the gate.

 

It is the bottom cill that is being talked about here, not the top cill. And the cill in question in one of the wooden blocks that the gate closes up against, not the big stone step at the top end of the lock chamber.

 

In all the cases of boats damaging cills that I have been aware of, the most usual cause is a boat passing over the cill when the water level is too low. Part of the boat's bottom hits the wooden cill blocks or even snags on it. When the wooden cills have been dislocated they no longer form a watertight(ish) seal with the bottom gate and it can become nearly impossible to fill the lock completely, as water rushes out under the bottom gate.

What you are talking about is actually the threshold, which is the wooden frame against which a gate rests when closed. Looking through the Bank Newton carpenter's day book for 1890, the only time they mention a wooden cill is in relation to a bywash or overflow, with thresholds being the name when dealing with locks. The cill, or sill, is the masonry to which the threshold is fixed.

 

In Germany, it is frowned upon to use your engine whilst passing over the cill in case they are damaged by the boat, and rubber tyres cannot be used as fenders in case they end up behind the gates or wedged in the paddle gear. All fenders have to float, so are often made from wood.

[MartinClark]

What you are talking about is actually the threshold, which is the wooden frame against which a gate rests when closed.

That may be so historically but this is what BW is calling a cill when they refer to boats damaging cills in stoppage notices. BW workers have shown me the wooden blocks when they have had the lock entrances drained down to carry out repairs and they have been calling them cills. This is obviously a confusing change in the use of terminology.

[billh]

That may be so historically but this is what BW is calling a cill when they refer to boats damaging cills in stoppage notices. BW workers have shown me the wooden blocks when they have had the lock entrances drained down to carry out repairs and they have been calling them cills. This is obviously a confusing change in the use of terminology.

Interesting picture that is Martin- especially all the junk & brickbats in the lock chamber. This junk is what damages gates and cills, not boats.

The rubbish gets trapped between cill ( threshold) and gates and water pressure as the lock fills distorts the gate or damages the wooden cill.

BW never clear out the lock chambers except around the gates during routine maintenance. The result is a lock chamber thats supposed to have 5ft of water (lock empty) has 2ft of water and 3ft of mud and rubbish. Bigger boats have to do lots of prop thrashing about to get in or out of the lock which makes the problem worse. There will always be these cill replacement stoppages until BW realise that the lock chambers have to be cleaned out regularly.

Bill

[Guest steve jenkin]

cant do the gates any good if you hit them for any reason . . . . "solution" dont f*****g hit them !!

[antarmike]

I can remember Croxley bottomlock had its gates hit, with about a foot of water in the lock. It broke the mitre post on the non towpath side gate. I don't recommend hitting gates.

 

 

 

I also remember Sam Horne (Berko lock keeper) telling me he had tried to run Fenny lock, without stopping, (which can be done).

 

You need a long, long line to the butty, so that after the motor has bashed through bootom, then top gates, you can get some speed on before the butty has to ram its way through.

 

Sam got it wrong, his line was far to short, and he got caught with the Motor going through the top gates, as the butty entered the bottom gates. He got stopped with both boats jammed between a pair of gates, and there he stayed for twelve hours whilst the whole of the long pound drained through Fenny lock, and he could get out.

 

He said he wasn't very popular!

Edited March 27, 2010 by antarmike

[mykaskin]

I can remember Croxley bottomlock had its gates hit, with about a foot of water in the lock. It broke the mitre post on the non towpath side gate. I don't recommend hitting gates.

 

 

 

I also remember Sam Horne (Berko lock keeper) telling me he had tried to run Fenny lock, without stopping, (which can be done).

 

You need a long, long line to the butty, so that after the motor has bashed through bootom, then top gates, you can get some speed on before the butty has to ram its way through.

 

Sam got it wrong, his line was far to short, and he got caught with the Motor going through the top gates, as the butty entered the bottom gates. He got stopped with both boats jammed between a pair of gates, and there he stayed for twelve hours whilst the whole of the long pound drained through Fenny lock, and he could get out.

 

He said he wasn't very popular!

 

Brilliant! Oh, fantastic story Mike. It's nice to know that even the good boatmen got it wrong from time to time, although if this is rather "advanced" boating technique!

 

I guess he had to make sure the swing bridge was out of the way also!!

 

Cheers,

 

Mike

[Pete of Ebor]

From a BW stoppage notice:

 

 

 

Now I've accidentally hit gates for a variety of reasons - mostly by forgetting how long it takes for the engine to build up speed - but how has the bottom gate cill got damaged in this case?

 

If hit from below the gates will open then shut again from the water pressure, and from above I wouldn't have thought enough shock would be transferred to the bottom, but mostly dissipated through the quoins.

 

Cheers,

 

Mike

 

First, I'm not a mathetmatician or engineer... but as I see it, the gate must make watertight contact with the lower cill or water would come through. There are lots of possibilities. Imagine...

1) Bottom gate in a full lock if hit (hard) by a boat entering the full lock from above - will dissipte the some of the force to the cill as the bottom of the gate must be up against the cill - though most of it will probably just break woodwork in the gate.

2) Bottom gate of a full lock hit (hard) by a boat approaching from below - could probably cause the gate to open then slam shut very hard. This slam could damage or even displace the bottom cill.

3) similarly, ascending in a lock, hitting the top gate could cause it to open and slam shut assuming the water level is above the cill of the top gate.

 

no doubt there are other scenarios like opening the bottom paddles too soon before the top gate is shut..

 

tin-hat on - waiting for flak...

[hughc]

The worst lock for rubbish in the chamber, that I know of, is Aston broad on the T&M. We always need flushing in and out of this- and not a gentle flush either. BW have been told on numerous occasions . They have a stoppage this winter to rehang the bottom gates which are inoperable by any one person unless he or she is built like a sumo wrestler.They have tried to correct the gates before but seem to have no one who understands the the way they are supposd to work. I bet that after the stoppage the rubbish is still in the bottom. Regards, HughC.

[owenk]

"dewatering"....."dewatering".....is that a word - do they mean draining or even the great Bushism I heard after the New Orleans floods "dewaterfication."

Edited August 2, 2010 by owenk

[Grace and Favour]

"dewatering"....."dewatering".....is that a word - do they mean draining or even the great Bushism I heard after the New Orleans floods "dewaterfication."

Should you use Google - you'll find an host of situations and industries that use the dewatering process

[Foxglove]

 

This was the damage to Unstead Lock on the Wey recently . The boat entered the lock to go downhill , hit the top beam pushing the top of right gate past the left one . Most of the cracking noises were heard when the boat reversed off and the gate sprung back a bit , accompanied by the sound of the top gates slamming behind it as the water started to rush through . The damage to the mitre post on the right gate is obvious , the less obvious damage in this photo is where the main body of the gate has cracked away from the heel post . The heel strap was broken and the quoin cracked also .

 

Apparently the steerer's comment was " oops , I haven't done that before " .

 

Hey ho !

 

 

 

Foxglove

[mykaskin]

Most impressive. Though the gates don't look too healthy, and don't look like they were built very strong to start with!

 

Mike

[Naughty Cal]

Most impressive. Though the gates don't look too healthy, and don't look like they were built very strong to start with!

 

Mike

 

They do look very flimsy when compared to other gates

[Foxglove]

more here http://www.canalworld.net/forums/index.php?showtopic=31876