I cannot for the life of me understand how they work on a canal for example. Please dumb it down as much as possible
In: Engineering
They’ve got two doors, and the boat goes in, they close both doors, and the doors are reasonably water-tight, so at this point there is no water coming through the doors, and the boat is in a little box where the water level is it’s own thing, and not related to the water level of the river.
If the boat is going *up*, they let water in through the bottom, and when the boat has floated up to the level of the water on the upstream side, they open the upstream door, and the boat sails off.
If the boat is going *down* they let water *out* through the bottom, and when the boat has sunk down to the level of the downstream side, they open the downstream door, and the boat sails away.
It is important to note, if they ever opened both doors, it’d be a crazy waterfall, so that’s not usually a thing. Also, if they just opened one of the doors without letting water in or out first, the avalanche of water would wreck the boat, and maybe break the other door.
Imagine you are walking up the stairs. Instead of stepping up, a door closes in front and behind you and raises you up to the height of the first step. The front door opens and you walk onto the step. Then it happens again, doors close and raise up to the height of the second step.
With a boat, they float into an area and get boxed in. The box is filled with water which makes the boat rise to the level of the next “step”. They then drive out at that level.
A lock is a place in a river where the elevation changes rapidly. Like at a waterfall.
so go to get around the waterfall a short canal is dug from the high side to the low side. and two doors are installed, one on the High side and one on the low side.
each door has a valve in it to allow water to pass through That can be opened or closed.
so what happens. If a boat on the high side wants to go through.
1. Make sure both lock doors are shut. Open the valve on the high side. The water from the high side will fill the lock with water until its water level matches the high side.
2. Open the high side door. Move the boat into the lock. Close the high side door. Close the high side valve.
3. Open the low side valve and drain the water out of the lock. As the was drains out the boat will descend. Once the lock water level matches the low side, the low side door can be opened. And the boat will leave.
if there is a host on the low side thst wants to go up, it will now enter, the door will shut, the low side valve will close and the high side valve will open and refill the lock (Going back to step 1).
The basic idea of a lock in a canal is to change the elevation of a boat to continue its journey. Put a toy boat in the bathtub, slowly fill the tub, the boat rises with the water level. Drain the tub, the boat lowers with the water level
So a boat coming into say, the Panama Canal, they enter the first lock. It closes behind them and starts filling with water. The boat floats, so it rises with the rising water level. Once it reaches the height of the next lock, it opens, and the boat proceeds forward. It continues this until it hits the top, in Panama’s case, Gatun Lake. On the way out, it does the same in reverse. The lock drains slowly, lowering the water level and lowering the boat.
A lock is a watertight chamber, big enough for a boat to fit into. It has gates which will only open when the water is equal level on both sides of the gate (it’s not possible to move the gates if the water is different levels, basically).
So the boat approaches one side – if the water isn’t level with the side they’re approaching from, they close all the gates and open the sluices at whichever side is needed to adjust the water level.
Once the water is the correct level, they close all the sluices and open the gate. Move the boat in, close the gate, open the relevant sluice to adjust the level, close the sluice again, open the other gate, move out and off you go.
On some waterways, the convention is to leave the locks either empty or full, in order to save water or for some other reason.
I find this kind of thing is [way easier with a visual.](https://www.reddit.com/r/gif/comments/3txykf/how_the_panama_canals_work/)
Each lock is two sets of doors.
* A door opens and the boat enters the space between the doors.
* The door closes behind the boat, so it’s now in the space between the two sets of doors, called a “lock”
* Water is pumped into or drained out of the lock, depending on whether the boat is going from low to high or high to low water.
* Once the water level in the lock matches the leaving direction’s water level, the door in front of the boat opens and it leaves.
water always flows downhill (unless you pump it back up).
A lock is two sets of doors that either block or allow water flow from the higher side to the lower side. by closing the lower doors, the water level inside the lock rises (with any boats inside) until it meets the water level of the higher side.
to lower the water level inside the lock, a smaller drain opens to allow water out until level with the lower side.
Practical engineering has a great and simple video (with models!) [https://www.youtube.com/watch?v=SBvclVcesEE](https://www.youtube.com/watch?v=SBvclVcesEE)
You got two doors that separates the canal into 3 bits – a high bit, a low bit, and a bit in the middle that can go up and down by pumping water in or letting it out.
If your in the low bit, they let water out of the mid bit until it’s at the same level, you float past the door and close it. Water then comes from the high bit to fill this bit until it’s at the same level, the second door opens, and you can float out onto the high bit. Going the other way is just reversing it.
Canals get topped up by allowing rivers to drain into them in places, they also have overflows in other places to stop them overfilling. These replace any water lost in the locks, so the canals stay full.
A lock can only go a few metres. If you need to go further up or down you can have lots of locks, called a flight – like this one near Fort William in Scotland called [Neptune’s Ladder](https://i1.wp.com/highlands2hammocks.co.uk/wp-content/uploads/2020/09/ariel-view-of-the-neptunes-staircase3.jpg?fit=1500%2C1000&ssl=1) or if you really want to go for it, [The Falkirk Wheel](https://wikitravel.org/upload/shared/b/b1/Falkirk_Wheel_Operation.JPG) shows how to replace lots of locks with on mind boggling wheel.
[It’s best seen in motion with an explanation](https://www.youtube.com/watch?v=qHO9gARac-w). I live near both, I’,m very lucky.
It’s basically an elevator for boats.
You bring your boat in, and they put water in or out to bring you up and down. When you get to your “floor”, you go out.
Ok so you have a boat and you’re in a bad neighborhood so take a lock and you chain up your boat and you keep the key
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