I CALL BULLOBAMA on this letter.
The rig the guy says he is on is currently being used off the coast of CUBA!!!!!!!!!
The closest rig to this Location is the TAM DAO 01.
@ 9.469483 / 107.8553
There is not a rig at the location in the letter.
This site has the rig off Vietnam.
http://www.rigzone.com/data/offshore_drilling_rigs/416/Semisub/Songa_Offshore_AS/Songa_Mercur
Good investigative work!
This whole thing is one confusing story after another.
The rig the guy says he is on is currently being used off the coast of CUBA!!!!!!!!!
The rig used to be off Cuba, but has since been moved to its present location.
http://www.offshoreenergytoday.com/songa-mercur-rig-leaving-cuba-for-vietnam/
That marinetraffic.com doesn't seem to be well-maintained. E.g., I search it for Songa Mercur. It comes back with a link listed as a drilling rig. But when I click the link, I get a 404. Oops. Tried the link again, and now it comes back with a map dated 2013-02-18 showing the rig off Cuber at 22.84518 / -79.38331. Newer locations available but cost $$.