▁deck ▁officer ▁qual ifications ▁on ▁a ▁Mer chant ▁Mar in ers ▁Cred ential ▁which ▁is ▁a ▁combination ▁of ▁the ▁former ▁Mer chant ▁Marine ▁Offic ers ▁license ▁and ▁Mer chant ▁Mar in ers ▁Document ▁in ▁a ▁small ▁book ▁that ▁looks ▁similar ▁to ▁a ▁pass port ▁and ▁is ▁issued ▁by ▁United ▁States ▁Coast ▁Guard ▁for ▁mar in ers ▁in ▁the ▁United ▁States ▁command ing ▁a ▁small ▁commercial ▁vessel ▁as ▁a ▁master , ▁captain ▁or ▁ski pper . ▁It ▁may ▁contain ▁a ▁sail ing ▁end ors ement ▁for ▁sail ing ▁vessels ▁and / or ▁a ▁commercial ▁to wing ▁end ors ement ▁for ▁vessels ▁engaged ▁in ▁assistance ▁to wing . ▁ ▁There ▁are ▁four ▁main ▁categories ▁of ▁lic enses , ▁some ▁of ▁which ▁have ▁sub categories : ▁O UP V ▁( Operator ▁of ▁Un ins pected ▁Pass enger ▁V ess els ) ▁Cred ential ▁O UP V ▁Limited ▁Cred ential ▁Limited ▁Master ▁Cred entials ▁Master ▁Cred entials ▁ ▁Oper ator ▁of ▁Un ins pected ▁Pass enger ▁V ess els ▁License ▁The ▁Oper ator ▁of ▁Un ins pected ▁Pass enger ▁V ess els ▁( O UP V ) ▁License , ▁commonly ▁referred ▁to ▁as ▁a ▁ 6 - Pack ▁License , ▁For ▁the ▁purpose ▁of ▁the ▁O UP V ▁end ors ement ▁an ▁un ins pected ▁passenger ▁vessel ▁is ▁a ▁vessel ▁of ▁less ▁than ▁ 1 0 0 ▁G RT ▁( about ▁ 6 5 ▁feet ) ▁carrying ▁six ▁or ▁ ▁fewer ▁passengers ▁for ▁h ire . ▁ ▁It ▁is ▁quite ▁popular ▁and ▁can ▁be ▁end ors ed