John, et al:

I couldn't locate "Few Survived" by Kemp, but I hold "Few Survived" by Edwyn Gray.

I went through "Sub Sunk" by Shelford also. These books do not offer anything with respect to using telephones with escape messenger buoys. Shortly after the USS SQUALUS salvage in 1939, the use of telephone communication was discontinued.

The U-57, hit a mine north of Scotland in 1915. She went down in 128' of water with 20 men alive inside. The air in the boat quickly filled with chlorine gas as sea water flooded the batteries. The fumes burned the men's eyes and made breathing nearly impossible. Their ears ached as pressure increased. They found only 4 "Drager" units aboard; believing their situation hopeless, 2 of the men shot themselves. Then the captain decided to make one last, desperate effort to save the remainder of his crew by opening a hatch.

To his amazement the hatch flew open and he was drawn out and upward. He had no time to inflate his life jacket or even to take a breath. As he recounted later,"I had no desire to inhale, but to forcibly exhale so that I constantly had
to blow air out." The air in his lungs had expanded as he rose. If he hadn't
exhaled, his lungs probably would have burst. The rest of the crew followed him; seven survived the ascent and were later picked up.

Hope this helps,

ROBERT M.