Not sure what forum this one belongs in so apologies.
I've gotten ahold of a number of certificates for a merchant navy ancestor which shows his progression up the ranks from mate to master. However there are 2 certificates for him, 3 years apart, for the same rank of First Mate. My question is could a certificate be taken from you or could you be "demoted" in rank (and hence lose a certificate) if something happened ?
any idea where I could find more about certificates from the board of trade ?