its a boat that is built to operate in a commercial climate and built to survey is to a higher standard than most (if not all) recreational boats.
Extra's will include but not limited to inbuilt floatation, extra hull thickness(?), heavier duty transom(?). All basically to not only prolong the life of the vessel, but to make it as safe as possible for comercial operators whether a charter opertator of pro fishing.
I don't know much about it all and have a verylimited understanding of it, but there are plenty of others here that can help.