This is how massive Navy ships get their fresh water
When ships deploy out to sea, it's important they bring the fuel and spare parts they need. The ship's crew also needs to be supplied. While food is often transferred to these ships, there's also the pressing need for the crew to drink.
Although they're surrounded by water, the ocean upon which these ships float isn't exactly the best thing to drink. The National Oceanic and Atmospheric Administration points out that if you drink sea water, you get more dehydrated and, ultimately, dehydration kills people. Drinking seawater brings about other health problems that can cause problems on board ship, specifically the head.
It used to be that ships had to carry water that was safe for drinking. This made crossing oceans difficult to say the least. The sailing frigate USS Constitution (ex-IX 21), one of the original six frigates built for the United States Navy, had a crew of 450. Humans need to drink nearly a gallon of water a day, according to the Mayo Clinic, which, as you can imagine, meant carrying a lot of fresh water as cargo.
Well, today, making sure the sailors have plenty of fresh water for all their needs is much easier. The Navy can do this thanks to the Light Weight Purification System. It just takes one sailor to operate, and it can handle anything from sea water to fresh water. According to a Marine Corps document, this system can purify 75 gallons of water per hour.
Seabees learn how to install nuclear, biological and chemical filters on the lightweight water purification system (LWPS) during training onboard Joint Expeditionary Base Little Creek-Fort Story. (U.S. Navy photo by Chief Builder Wesley Harris)
The Navy, of course, has other systems that can handle larger amounts, but the Light Weight Purification System is very mobile, which becomes very useful for Marines on the front lines. Learn more about this system in the video below: