46 CFR §47.620

1. (a)A plimsoll mark (disc and line through center) applicable to International service must be placed at the draft corresponding to 15-degrees of righting energy as calculated in fulfilling the requirements of 46 CFR 174.015(a)(1).
2. (b)The seasonal ladder representing summer, winter, and winter North Atlantic seasons must be as shown in Figure 1 below.
3. (c)An equivalent Great Lakes summer seasonal line must be placed on the seasonal ladder at the draft corresponding to 10 foot-degrees of righting energy as calculated in fulfilling the requirements of 46 CFR 174.015(a)(2) and be marked with a (T).
4. (d)The fresh water mark may be omitted by request of the owner or operator.