Contrary to my suggestion that SYSONBY may be a misspelling, I can confirm that there was a ship by this name.
According to http://www.searlecanada.org/sunderland/sunderland028.html, a ship named BOVERTON was built in 1910 in Sunderland, a coastal city in north-eastern England. She was sold and renamed LLANGORSE in 1928, then sold again in 1930 to a shipping company in Estonia and renamed MARET. Scroll well down the page to #73. The same page contains a poor-quality photograph of the ship, not indicating the year.
In July 1941 the U.S. government seized a number of foreign-flagged vessels then found in U.S. ports, for possible utilization in war, when and if the U.S. became involved in World War II. Among the ships seized was MARET, identified as an Estonia ship. (See http://www.usmm.org/foreign.html; note the statement on the page that some seized ships were named after race horses.)
Subsequently (again referencing http://www.searlecanada.org/sunderland/sunderland028.html), MARET was renamed SYSONBY and sailed under the Panamanian flag throughout World War II, operating on routes to and from Caribbean ports and Key West. She was scrapped in 1951.
A Google search of SYSONBY indicates that this was also the name of a U.S. race horse from the early 1900s. This matches the notation at http://www.usmm.org/foreign.html, which mentions MARET but not her name after being requisitioned.
Ron Carlson, Webmaster
Armed Guard / Merchant Marine website