People are just finding out why tug boats spray water into the air when towing ship

If you've ever been to a port and gazed out to sea, then you'll have seen the mighty metal behemoths of the day chugging their way about the waves.

Look down a bit, and there's also a good chance you'll see the much smaller vessels designed to move the much bigger ships into position. these are the humble tug boats.

You can probably guess why they're named that, but the job they do is really quite incredible as they help add some finer touches of movement to the larger and more lumbering aspects of the bigger ships.

Have you ever tried to do a three point turn with a cruise liner? Nightmare.

Sometimes the tug boats have to give boats a tug to get them pointing in the right direction and at other times it's more of a shove.

The tug boats will sometimes perform a 'water salute'. (Mark Metcalfe/Getty Images)

These smaller but vital vessels perform an important duty out on the waves, and we haven't even mentioned the fact that they can also be used for salvage and to break through ice.

If you like watching tug boats then you might have wondered why they seem to spray out jets of water when they're doing their job.

There's actually a few reasons for this, with one of the main ones being that it makes for a good firefighting tool should the need arise, while another reason is that it helps keep the large engines which power ships cool and it doesn't even waste any water because it all goes back into the sea anyway.

Using the water spray is also helpful in a tug boat's main duty of tugging around other boats as firing out the water can help the vessel with some of the more nimble moves it's possible to pull off.

Finally, there's a very nice other reason behind it happening sometimes which is known as the 'water salute'.

The water salute is a way for the tug boat to show appreciation. (Andy Newman/Cunard Line via Getty Images)

If the tug boat wants to acknowledge another ship for any reason then it can use the water salute as a demonstration.

The salute can be used to either welcome or bid farewell to any ship that's either coming into port or leaving it, and it can also be deployed just because the crew feels like celebrating the occasion.

The water salute isn't just done on the sea either, as fire engines can also perform it for planes that are being piloted by someone who is undertaking their last ever flight before retirement.

When Concorde set off from John F. Kennedy Airport in the US for the final time it got a water salute, and the gesture is also sometimes performed for flights carrying the remains of soldiers who were killed in action.