If you've ever seen a tug boat towing a ship, you might have noticed it sometimes starts spraying out huge jets of water.
It's a bit of an extra display, particularly for what's normally a small boat - and there's actually a reason behind it.
A clip has gone viral on X (formerly Twitter) recently, showing a small tug boat doing its thing.
The video from the @historyinmemes account has clocked up 62.9 million views, and shows a red and white tug boat spraying an impressive amount of water out from the vessel in large jets.
It looks pretty cool, and the post asks the simple question: "Do you know why they're spraying water?"
Advert
You might wonder if there's some practical reason for the display, but one viral response has cleared that up immediately. The history-focused account @timecaptales commented: "Tug boats do this, called a Water Salute. It’s a ceremonial custom, celebrating the arrival or leaving of a particular vessel. The water is sprayed from the firefighting hoses on the tugs, and is sometimes coloured."
It went on to explain that the cannons themselves are not put on the boats purely for this reason, though - they do have some functional uses. It can also help clean off the sides of boats, as well as being a fire-fighting tool if blazes erupt on other vessels.
People are pretty amazed in the replies under both the original video and the response explaining it, and there are plenty of jokes flying around, too.
One user wasn't satisfied with the logical explanation, and suggested: "You have to water the ocean so that it grows", while another had a similar idea: "They are filling the ocean with water, so the ship can keep floating. Simple as that!"
Many others have chosen to add their two cents in a more informative vein, though, with one user chiming in to explain a little more seriously: "They do this because it is the first time there sailing to this port. I work in the port of Rotterdam. Every ship thats new, its first port is always Rotterdam. So I can tell."
From people's experiences in the replies, it's clear that there are quite a few reasons to prompt this sort of display from a tug boat, whether it's something cute like a ship captain's birthday, or a major milestone like its 100th voyage.
Either way, it's a good example of how a viral video can give us all a quick lesson on something we were totally clueless about.