To the best of my understanding, unless your vessel has a manning certificate and you are filling one of the positions specified in that certificate (vis. you are crew and not an “industrial personnel”) then you are not earning specific sea time towards upgrading any seaman’s papers you might now have. However, if your vessel is uninspected and under 200grt, your seatime can be documented on a “Small Vessel Sea Service Form (CG-719s)”.
.