The special timber load lines are marked on the ship’s sides as follows (the “L” standing for “lumber”, another word for wood):
LS = The Summer Timber Load Line indicated by the upper edge of a line.
LW = Winter Timber Load Line.
LWNA = The Winter North Atlantic Timber Load Line. This is level with the WNA Line.
LT = The Tropical Timber Load Line.
LF = The Fresh Water Timber Load Line in Summer.
LTF = The Fresh Water Timber Load Line in the Tropical Zone.
In all cases the freeboard is indicated by the vertical distance from the upper edge of the deck line to the upper edge of the load line in question.
The lumber freeboard is less than the normal summer freeboard to indicate that the timber may add to the ship’s superstructure volume and thus improve the reserve buoyancy.
Why do timber ships have different load line markings compared to other ships like container ships, bulk carriers, etc.?