I will be working between Thailand and Myanmar on a vessel and was told their is a passbook that acts like a passport for the vessel you are working on so you do not have to pay Myanmar fees. Does anyone know the exact name of this passbook, some have said it was a sea card, others called it some sort of passbook. Does anyone know the exact name for this?

It's called seaman's book. It is issued by the country in which the vessel is registered. Application will usually be done by the ship's owner on behalf of their crew. Actually, this is general information, I don't know whether this applies to Myanmar in particular.

I suggest you talk to your new employer about it.