If you pre-book a passage on the lift you have to pay, if you just turn up and take your chance it is free, so we just turned up and as it happened exactly at the right time. There are reserved moorings outside the visitor centre for boats going down the lift which is where I moored, even though I wasn’t booked to go down.
I went into the visitors Centre and enquired at the desk about going down onto the river and got directed to a reception office with a service window down stairs. Here beside the window id a door bell for service which I pressed and waited. Eventually an employee who had been upstairs came down and went into the offices, not to the serving window and then came out again telling me the lady I needed to see knew I was waiting but would be about 5 minutes as she was busy. As her tea was on her desk I knew this must be the truth. The a man in CRT uniform came down and asked if it was my boat moored on the reserved mooring and if I was going down the Lift, I replied yes to both. At that point he called on his radio to open the top gate and said could I please hurry. The Lady eventually came to the window and asked the boat name and number. The chap wrote these down and was off. I had to give her my name, address, boat length, mobile phone number. I said I was surprised she didn’t know that from the registration number, but its a separate computer system. I even had to give my full address as it wasn’t tied into the post code system, they must have bought it cheep somewhere. Once that was sorted I went back up to the boat.
At the boat another chap was waiting, he would be loading me onto the lift so wanted to tell me the procedure then we were away. As soon as an oncoming boat had passed I turned in under the bridge and headed for the lift.
Through the bridge is a basin and this connects to the lift caisson by a trough 14+ft wide and 80+ft long. At each end of the through is a guillotine gate. at no time are both guillotine gates open. So the procedure is you enter the tough and stop a stop sign. The Chap loading the boats then closes the guillotine gate behind the boat.
They now raise the guillotine gate at the the other end of the trough and the one on the inlet to the caisson simultaneously via an automatic linking arrangement that is operated by counter weights and gravity. The boat is now driven forward into the caisson and securely moored at the stern, I would imagine that a full length boat would require mooring at both ends or it would be to far forward.
The pair of gates are then lowered behind it. When the weight is off the wire the catch disengages and allows the caisson to be lowered.
Once the caisson and trough gates are closed the water is drained from between them, this proves that both gates are sealed.
From our point of view we were now ready to be lowered, but they have to consider the other caisson which is at river level and being loaded with a trip boat to come up. Once both caissons are ready the journey begins, it is a little bit bounce as you start to move but after a foot or so is very smooth. As one caisson falls the other is rising.
To get a watertight seal between the caisson and the trough at the top the faces are angled with a rubber seal 
so as the caisson reaches the top of its travel it pulls tightly against the end of the trough. This seal is checked by filling the void between the gates with water before the guillotine gates are drawn.
Each caisson is mounted on top of a single hydraulic ram, the rams are interconnected hydraulically so the two caissons are balanced and only a small amount of pumped pressure is required to raise one caisson while the other falls. Originally this hydraulic fluid was the water from the river Weaver but over the years it caused server corrosion so now its on a closed oil system.
Once the caisson has reached the bottom where it sits in a dry pit a wedged joint is pulled up tight between the end or the caisson and the river gate frame to make a water tight seal, 
the void between the caisson guillotine gate and the river guillotine gate is pumped full of water and checked for leaks then the gates are again simultaneously lifted with a similar latching mechanism as used on the top gates. Once the gates are lift its just a matter of starting the engine, untying and motoring out.
The journey time from entering the top trough to leaving the bottom gate was just 15 minutes.
A video of our trip down on the lift, sorry about the sound track
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