The flag at the stern of your boat is either a U.S. ensign, a yacht ensign, or a USPS ensign. A national ensign flown at the flagstaff should be one inch on the fly for each foot of overall length of the vessel. So a 30 foot vessel should fly a national ensign that has at least a 30 inch fly. All other flags on power boats should be 5/8 inch on the fly for each foot of overall length.
Powerboat or
|
|
US Ensign Size |
up to 20' |
12x18" flag |
|
21' to 24' |
16x24" flag |
|
25' to 30' |
20x30" flag |
|
31' to 36' |
24x36" flag |
|
37' to 48' |
30x48" flag |
|
49' to 60' |
3x5 ft flag |
|
61' to 72' |
4x6 ft flag |