I believe I found the info on one of the Naval Reenactment sites. May have been the Larboard Watch. They had the dimensions for the hammock and the mattress and cover. They also had a pattern for an under shirt and some other items. Its been about 5 years since I made it, so I don't know if they are still posted. Maybe someone from the site that had the info will post here.
John R Denley
POIC Memphis Detachment
CS Navy