Go to the US Coastguard site for the form CG-719S
This is where you record all the hours of sea service.You sign off on your own sea service on a boat that you own or owned, but you will need to attach a copy of proof (ownership, insurance etc) If the service is on someone els's boat that owner or party must sign the form. In fact you can find all the forms & info on their site. I went thru a mariner school, where they collated all the paperwork which basically comes from the US coast guard site. I just got mine in January and then discovered you will need to throw another 100 to 135 to the gov't for a TWIC card-Homeland security clearance for all merchant mariners and transport drivers. So look forward to more paper work. I did not hire anybody to fill out all the paperwork for the license you can easily do it yourself if you can follow directions.