Alden 1979, Part V. Note: Alden makes a rare error here. Guitarro and Hammerheaddid not receive the standard U.S. Navy "Fleet Snorkel" conversion prior to transfer, as he stated in the Part V addenda. See USN Photo NY9-21880-7-54 for Guitarro and Navsource.org photo 0836472b for Hammerhead. Although they did receive full snorkel installations, Guitarro and Hammerhead's conversions were very similar to Jack and Lapon in that their conning tower fairwaters and snorkels received only a partial streamlining. The periscope shears and covered wagon ribs were left exposed. The official Fleet Snorkel conversion had a GUPPY-style fully enclosed and streamlined fairwater/snorkel, hence called a "sail". The confusion probably stemmed from the fact that in post-transfer overhauls (probably done in the U.S. but paid for by the Greeks) both ships received GUPPY-style sails. Alden, John D., Commander (U.S. Navy Ret) (1979). The Fleet Submarine in the U.S. Navy: A Design and Construction History. Naval Institute Press. ISBN0-85368-203-8.{{cite book}}: CS1 maint: multiple names: authors list (link)
