You might be able to use those to fill the tanks on a boat, but, they are probably not approved as portable fuel tanks on a boat.
What issue are you trying to solve? My neighbor used to put lots of 5G Jerry cans in his 20' boat and go to the canyon to fish. Never seemed smart to me, but he lived...
My friend uses the same type of drums . I am only going use them to storage gas for about 6 hours when I get to my location I will pump the gas in my boat. And never use them for long periods of time for gas storage