Which Flashing Light Tells You to Enter a River Lock?

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Are you interested in a water navigation system? If you are, you must have heard about river locks. These locks are generally placed near the river docks. The main purpose of these river locks is to either lower or raise the watercraft.

There are different types of flashlights that tell you when to enter the river lock and when to wait. If you see an amber light, it means that the boat can approach the lock safely and at a reduced speed.

But, you can only enter the river lock if you see a green light. In the case of docks, you can see special dock light. Don’t confuse it with the river lock traffic lights.

What are the meanings of different colors of flashlights?

Like traffic lights, these river lock lights can either be fixed or keep blinking. Let’s read the following paragraphs to know the significance of both of these blinking and flashing lights.

Red light

If you see a fixed red light, you can assume that the lockmaster is unable to see your boat approaching the river lock. Sometimes, when the lockmaster couldn’t acquire proper information about your boat, he keeps showing a fixed red light. You can turn on the marine navigation light of your boat to make it visible in low light. If there is some other watercraft entering or exiting the river lock, you will get to see a red blinking light. It tells you to stay away from the lock and to maintain a certain distance.

Amber light

Amber color is shown after the red light and before the green light. This particular lock light tries to tell the boat operators to come towards the river lock slowly at a controlled speed. There will be times when you will get to see both amber and green light simultaneously. It means you don’t have to be cautious at all while entering the river lock.


Next, you can see some flashing green light. This light tries to tell the boat operator that everything is clear, and you will get to hear a high-pitched horn sound providing you the permission to enter the river lock at that time. By the way, this horn sound lasts for a few seconds.

What does a river lock do?

The locks help the water vessels to switch between two different water levels. Generally, you will get to see locks in the river, canal, etc. A river lock is made of multiple components such as two gates, a filling valve, a lock chamber, and a drain valve. When the boat gets a green signal from the lockmaster, he instructs to open the filling valve at first and opens the first gate.

Once the boat enters the lock chamber, the first gate is closed, and the second gate is opened. The draining valve opens itself and drains out all the water to bring the boat to a lower level of water. While the boat or ship is in a lock chamber, the anchor and the anchor rope should be kept onboard. If you wish to climb from a lower water level to a higher water level, the river lock system will follow the entirely opposite strategy.

What are different types of river locks?

There are multiple types of river locks such as flood locks, drop locks, stop locks, lock flights, flood gates, staircase locks, etc. All these types of locks use similar traffic light systems of red, amber, and green.

River locks follow a similar traffic light rule as that of road. So, if you are about to buy a boat in the near future, you should start learning about the rules of the river and canal locks.