Castle Island Lighthouse, which U-183 under Schafer utilized as a navigational aid in 1943.
Source: Capt. Patrick Childress, http://www.sailblogs.com/member/brickhouse/?xjMsgID=48400
Korvettenkapitän Heinrich Schäfer in the first IXC4 boat to enter the area, U-183 entered westbound south of Bermuda on the 2nd of February 1943. Proceeding west for two days he then took U-183 southwards on its second of eight patrols out of Lorient to pass west of Mayaguana and then east of Inagua, utilizing both the Crooked Island and Caicos passages during the 27th and 28th of February.
On the 1st of March Schäfer and his crew transited into the Windward Passage, passing Guantanamo on the 2nd, westbound south of Cuba. On the 11th of March he sank the 2,493 Honduran freighter Olancho in the Yucatan Channel. Schäfer then took his boat south southwest into the Gulf of Guatemala and off the coasts of Belize and Honduras before sweeping east south of the Caymans, Jamaica, and Hispaniola.
Schäfer was to return in the boat via the Mona Passage on the 14th of March, heading on the conventional course north-northeast until it reached roughly the same area it entered. On the 18th of March U-183 headed northeast back to Lorient and the Second Flotilla. The boat was refueled by U-117 south of the Azores – she had used up a week’s worth of fuel pursuing a UK-Gibralter convoy at the outset of the patrol (Wynn, Vol. 1, p.137). She returned to Lorient on the 3rd of May 1943.
A member of the Crew VII of 1925 who turned 35 on the 30th of January during this patrol, Schäfer sank two ships of 8,582 tons and received no decorations of note. Following its Caribbean patrol U-183 was sent from Lorient to Penang, Malaysia and then Singapore, on a voyage taking 122 days inclusive. While in Asia he briefly commanded UIT-23 but undertook no war patrols in her. Schäfer died of natural causes (paratyphus and appendicitis) in Tokyo, Japan on the 4th of October 1944, less than a year after becoming Fregattenkapitän.
SOURCES: Gudmundur Helgason, Rainer Kolbicz, www.uboat.net, 2011, Kenneth Wynn, U-boat Operations of the Second World War, Volume 1 and Volume 2, 1997