Talk:Caisson lock

message: What an amazing piece of engineering. One thing that is not clear from the article is how water is retained in the cistern. Clearly the caisson decends to the bottom of the cistern. I assume that there is a door at the bottom of cistern to match the door in the caisson. Is this true? How does the caisson seal against the cistern to prevent water escaping? 203.23.210.116 22:25, 10 October 2006 (UTC)
thread_title:  More detail please 

message: Is the diagram right? AFAIK the caisson couldn't be lifted above the water level, because of the weight of the ballast. Instead, the chamber wall was built higher than the water level in the top pound, and filled right up. There was an opening, normally closed by a guillotine-style door to keep the water in, into the top pound. Only when the caisson was in place tightly against the frame of the outer door, and a little air pumped into the space between them to equalize the pressures, was the door wound up to admit the descending boat. The same thing happened at the bottom: the increased water pressure improved the seal between the caisson and the door frame but the doors were forced solidly closed until air was pumped between them (at a higher pressure, of course). The pump was in the caisson and operated by the boat crew. Does any of this make sense? I can't draw, otherwise I'd try to fix it   ––Old Moonraker
Well the one existing diagram is a little unclear but looking at it again It appears you are right. I'll fix the diagram.Geni 11:03, 13 October 2006 (UTC)
replies: text: Added the above information, but disregarding the stuff about air pressure:  Equalisation was achieved just by opening and closing taps/faucets.  ––Old Moonraker 15:24, 13 October 2006 (UTC)
replies: text:  I've managed a tweak on Geni's caisson lock diagram to show the full-height cistern, as suggested. I've also simplified the labelling. May I upload it and try it in the article (full attribution to the original source, licensing as before, of course)?  If it doesn't work I'll take it out Old Moonraker 11:22, 28 October 2006 (UTC)
replies: text: Fine by me - I've left a note on User:Geni's talk page as the original creator.— Rod talk 11:28, 28 October 2006 (UTC)
thread_title:  Diagram 

message: I had to check on this as I was confused as well (see edit history). Originally "caisson" meant a water-tight box and "cistern" was a underground water storage chamber (not in the loft, as now). To our minds today this seems strange, but only because of the modern engineering use of "caisson" to mean a vertical, water-tight tower used underwater for excavations, concrete-pouring etc. It's the vertical, water-tight tower bit which would cause anyone a bit of doubt! Old Moonraker 19:11, 13 October 2006 (UTC)
replies: text: The names make more sense if you think of this as an underwater boat lift.Geni 01:27, 14 October 2006 (UTC)
thread_title:  Caisson/cistern 

message: Although the article does not state anything on the subject I take it all the tests and also if the plan had gone ahead would have been an unmanned vessel? I know I wouldn't want to be entombed in water with the chance of mechanical or structural failure, not quite the same as getting stuck in a lift. Boothferry (talk) 15:57, 1 January 2011 (UTC)
replies: text: As it's currently written, the penultimate test had the vessel carrying 60 people, and the final failed test (see the Abandonment section) was with a boat carrying a group of investors. So, it seems the vessel was manned, and I presume that was the intention had the project proceeded. (I would imagine it's easier to get the boat out of the caisson if it's already got someone aboard.) --David Edgar (talk) 19:30, 1 January 2011 (UTC)
replies: text: Yeah but christ I wouldn't fancy it! I'd get off at the top and back on at the bottom. Barges aren't too hard to drag around with ropes. Who fancies a trip in a massive leaking coffin to the bottom of a 50ft tank? I might imagine investors, who've put a lot of money into the thing, might see the point of demonstrating how reliable it was. And I suppose hydrophobia wears off after enough time working on boats, but that's not a job for me! 188.29.165.134 (talk) 02:47, 27 November 2013 (UTC)
thread_title:  Unmanned? 

message: The lead section claims, "... a conventional boat lock, which required a volume of water equal to a boat and its cargo weight for each lock used in a flight between levels."
The citation given fails to mention the claim so is an invalid cite.  In any case it isn't true.  The volume of water required to operate a conventional lock is the difference of the water volume of the chamber between the two water levels less the water displaced by boats and their cargo.  Further, in a flight of locks, only one such volume is required regardless of the number of locks in the flight, just as that same water volume operates a series of locks for the same boats. 109.153.242.10 (talk) 17:09, 21 January 2012 (UTC)
replies: text: It's been taken out a couple of times already—striking it once again. --Old Moonraker (talk) 07:50, 22 January 2012 (UTC)
thread_title:  Dubious claim in lead. 

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thread_title:  External links modified 

message: I'm not sure why it mentions that boat lifts need engines to lift them, I have never seen a single operating lift-lock that requires an engine to lift the chambers. All the ones I have seen use a counterweight system in which more water is put in at the top than the bottom, and lifting force is provided via hydraulic ram or cables where the heavier of the two chambers pulls/pushes the other up as it descends. I think that section needs to be looked into more deeply.  — Preceding unsigned comment added by 70.76.56.93 (talk) 13:33, 1 March 2020 (UTC)
thread_title:  "Comparison to boat lifts" 

message: I am moving the following uncited material here until it can be properly supported with inline citations of reliable, secondary sources, per WP:V, WP:CS, WP:IRS, WP:PSTS, WP:BLP, WP:NOR, et al. This diff shows where it was in the article. Nightscream (talk) 14:45, 26 April 2022 (UTC)
replies: text: The article now doesn't make sense as the section on abandonment makes reference to content that you've removed. 87.75.117.183 (talk) 01:07, 18 March 2023 (UTC)
thread_title: Uncited material in need of citations

message: The first paragraph uses present tense suggesting that in some senses such a system is still in operation. I would suggest changing is to was... Lawrence18uk (talk) 05:24, 14 May 2023 (UTC)
thread_title:  Is? Or was?