33 CFR §401.6

1. (a)Vessels of more than 20.0 m in overall length shall be correctly and distinctly marked and equipped with draft markings on both sides at the bow and stern.
2. (b)In addition to the markings required by paragraph (a) of this section, vessels of more than 110 m in overall length shall be marked on both sides with midship draft markings.
3. (c)Where a vessel's bulbous bow extends forward beyond her stem head, a symbol of a bulbous bow shall be marked above the vessel's summer load line draught mark in addition to a + symbol followed by a number indicating the total length in meters by which the bulbous bow projects beyond the stem.