Here is a question that no one has ever been able to explain to me. Hopefully one of you Engineering guys can answer.

A couple times I had to go TAD to Royal Navy ships (example HMS Brave). Everytime I went to a British ship their main job was to get me drunk (Yes, the Royal Navy can drink on their ships, and they loved us Yanks). We use to sit around and just drink, which was really fun.....
When you get ready to leave the ship, all the crew will give you their address so they can come visit the "Yank" base so they could load up on supplies. I thought they meant food, however, they wanted blenders, toasters, can openers, basically anything that had 120 volts. Then I noticed that every convenience outlet on the ship was 120 volts.

What I found strange is that their country is all 220 volts, but yet their power on the ship was always 120 volts. Why? The Power Plant was Rolls Royce. So it was British built. So what is the reason?

I orginally posted this in the US Navy section http://forums.military.com/eve/forums/a/tpc/f/297192721/m/9100074481001

I came out of the RN in 1970 and as far as I remember the main supply was 440v AC (660v Peak) for main power. This was transformed down to 115v AC (not 120v)which relates to the Peak voltage. The reason therefore was that each phase could use a 2:1 step down transformer. besides which there was less chance of a fatal shock with the lower voltage. In the older ships post war the ships supply was 220v DC which meant heavier cabling and the live to earth potential of fatal electric shock therefore heavier insulation and even more weight. We also had other suppliers 24v DC for telephones (backed up with batteries) and 230v AC for some radio equipment.
Hope that helps. Did we really get you drunk?

Regards

George