Previously, we examined how to use a toilet on a submarine. In this post, we’ll examine how to use a shower on a submarine. In contrast to the heads, showers on submarines are much more straightforward because they’re showers…plain and simple. Even then, the process is a bit different than at home due to certain constraints. USS Blueback has two showers for 77 enlisted sailors to share, and one shower for the eight officers to share; for a total of three showers.

How is freshwater made on a submarine?

1 of 2 freshwater stills on Blueback in the engine room.

Two evaporator stills on Blueback produce fresh water. These stills boil seawater and collect the condensation (which is fresh distillate) because salt doesn’t vaporize below boiling point. Blueback‘s two stills are each rated to produce roughly 60 – 100 gallons of freshwater per hour. So in theory, you could get 200 gallons an hour, but in reality, that was hardly ever achieved. There are 2 potable water tanks totaling about 3,100 gallons and 2 large freshwater tanks totaling about 11,100 gallons. This gives us a total of around 14,200 gallons of freshwater.

Limited water usage

Despite all of this freshwater, the cleanest (and twice-distilled) water isn’t for the crew to use. It goes to the lead-acid batteries. Blueback has 504 cells for a total of over 300 tons of batteries which need to be refilled with distilled water every day to keep running. After the batteries get water, next comes cooking, drinking, and cleaning. Then there might be some left for the crew to take a shower.

Note: A former sailor on USS Barbel (SS-580), a sister submarine to Blueback, told me that the amount of freshwater used by the batteries is not necessarily a huge amount, but it needs to be the cleanest and most distilled water. In reality, most of the freshwater is actually used for cooking, drinking, and cleaning.

Taking a shower on a submarine

The long, luxurious hot showers you take at home are what sailors call “Hollywood showers” and are a no-go on ships and submarines because they waste too much water. So submarine showers are a very basic process. They last about 1 – 2 minutes and are ice cold!

  1. Turn on the water for 10 seconds and get wet. Turn the water off.
  2. Lather up with shampoo and soap. Scrub, scrub, scrub!
  3. Turn on the water for 45 – 60 seconds and rinse off. Turn the water off.
  4. You’re done. Get out.

Your next shower will be in about 1 week…if you’re lucky. More than likely, you’ll shower once every 2 – 3 weeks on a diesel-electric boat like Blueback. However, Rick Neault (a former crewmember on Blueback) once told me that during one patrol, he went 54 days (almost 8 weeks) before he got to take a shower!

The only people who would be allowed to shower every day and use as much freshwater (within reason) as they needed would be the cooks and the corpsman for obvious health reasons. One makes meals and the other attends to health issues.

Yes, there is hot water and Blueback has three water heaters, but much like your home, it doesn’t instantly come out of the faucet hot. To let the water run as it heats up is wasteful on a submarine. So regardless, your shower is still cold. (The hot water is mostly used for dishwashing and handwashing.)

Other uses for the shower stalls

Since the enlisted showers are directly aft of the torpedo room, which is heavily air-conditioned, the showers are also fairly cool in terms of temperature. So they’ll be used to store food. Any place to store food on a submarine will be used; that includes the showers. So they’ll be full of fresh produce and other food for about a month. Nobody is using the showers anyway.

If you are going to shower, you need to first get permission, then pull all of the food out, take your shower, wipe the shower completely dry with your towel, and then put all the food back in when you’re done… in the exact order that you found it. That will take longer than it did to actually take the shower, and you’ll probably need another shower when you’re done (which you won’t get for another week or two).

Modern Submarine Water Plants

Modern nuclear subs use a more efficient process of making freshwater called Reverse Osmosis (RO). Seawater is essentially pumped through a semi-permeable membrane that filters out salt and other impurities. As a result, there is more freshwater available on a nuclear submarine, so showers are usually daily and actually hot…although you still have to conserve water by taking a quick shower. One submarine sailor told me that on his boat, they would sign up for a time slot to shower so everybody wasn’t just lining up to take a shower at the same time.