Lock Pickers

Have you ever wondered to yourself  

"What is a lock?" 

or perhaps 

"How on Earth does a lock work?"

Well, here I am to give you a little lesson, from what I've learned from our river boat experiences..... and with help from Wikipedia.

A lock is a device for raising and lowering boats between stretches of water of different levels on a river and canal.  Locks are used to make a river more easily navigable, or to allow a canal to take a reasonably direct line across land that is not level.

There you go.... does that make sense?

Not really?

Here are some pictures to help.

There are all kinds of locks.  You've got your staircase lock, your double lock, your pairs lock, your twinned lock and your stop locks.  You got your round lock, your drop lock, your bi-directional lock, your tidal lock and your inlet lock.  You've got your turf sided lock, your flash lock, your caisson lock, your diagonal lock and your pound lock.

All pound locks have three elements:

• A watertight chamber connecting the upper and lower canals, and large enough to enclose one or more boats. The position of the chamber is fixed, but its water level can vary.
• A gate at each end of the chamber. A gate is opened to allow a boat to enter or leave the chamber; when closed, the gate is watertight.
• A set of lock gear to empty or fill the chamber as required. This is usually a simple valve (traditionally, a flat panel (paddle) lifted by manually winding a rack and pinion mechanism) which allows water to drain into or out of the chamber; larger locks may use pumps.

The principle of operating a lock is simple. For instance, if a boat travelling downstream finds the lock already full of water:

• The entrance gates are opened and the boat moves in.
• The entrance gates are closed.
• A valve is opened, this lowers the boat by draining water from the chamber.
• The exit gates are opened and the boat moves out.

If the lock were empty, the boat would have had to wait 5 to 10 minutes while the lock was filled. For a boat travelling upstream, the process is reversed; the boat enters the empty lock, and then the chamber is filled by opening a valve that allows water to enter the chamber from the upper level. The whole operation will usually take between 10 and 20 minutes, depending on the size of the lock and whether the water in the lock was originally set at the boat's level.

Boaters approaching a lock are usually pleased to meet another boat coming towards them, because this boat will have just exited the lock on their level and therefore set the lock in their favour — saving about 5 to 10 minutes. 

This was the view from our balcony as we entered the chamber

And this is the view as the chamber empties and the boat goes down

This is what you get to look at from the balcony while the boat goes down.

Unless you stick your head out - which you're asked not to do, and then you get this view.  It's amazing how these river boat captains managed to get this size boat through the locks without hitting the sides.  

There's not much room for error!

So, there you go.  Everything you need to know about locks.

Any questions?