The forward engine room contains main engines #1 and #2. At the forward bulkhead of this compartment, you will see 2 stainless steel barrel shaped objects. These are the evaporators that distill sea water into fresh water. Their invention was a tremendous boon to submarines, but the use of fresh water was still limited by their small capacity. Rated at 1,000 gallons per day they rarely produced combined total of more than 750 gallons per day. Most of the water was needed by the storage batteries and engines, the rest for cooking. Operating the stills also consumed fuel, and conservation of fuel was one of the most important factors in ensuring the success of the war patrol.