DRAFT
The draft of a vessel is the distance that it is immersed in the water or the depth from the bottom of the keel to the water line.
Draft marks are painted on both sides of the stern and rudder post in the following manner: The numerals are six inches high with six inches space between them and the bottom of each numeral rest on an even foot of draft. This method makes it possible to estimate by eye the inches of draft, if the water covered half a number the
draft would be equal to that number of feet plus 3 inches.
FREEBOARD AND LOAD LINES
The freeboard of a vessel is the height above the water level to the top of the freeboard deck measured amidships.
A load line is a line that limits the maximum mean draft so that there will be sufficient freeboard and reserve buoyancy to insure the safety of the vessel. The position of the load line on American ships is determined by the American Bureau of Shipping and indicated on the sides of the hull by Plimsoll marks. Plimsoll marks consist of a disk with a horizontal line through its center, indicating the summer load line, and a series of other horizontal lines indicating the load lines for various waters and seasons. The abbreviations used to mark these lines are :
F or FW - FREASH WATER.
IS - INDIAN OCEAN IN SUMMER.
WNA - NORTH ATLANIC IN WINTER.
S - SUMMER IN WATERS OTHER THAN INDIAN OCEAN.
W - WINTER IN WATERS OTHER THAN NORTH ATLANIC.
T - TROPICAL WATERS.
TF - TROPICAL FREASH WATERS.
