Sea state refers to the height, period, and character of waves on the surface of a large body of water. The large number of variables involved in creating the sea state cannot be quickly and easily summed, so simpler scales are used to give a rough description of current conditions, primarily for reporting in a ship's log or similar record.

Bowditch 1938

The 1938 edition of the US Navy Hydrographic Office publication No. 9 includes the following scales:

Direction from which swell is coming should be recorded.

Confused swell should be recorded as "confused northeast," if coming from the direction of northeast.

References

• Bowditch, Nathaniel original; H.O. pub No. 9: American Practical Navigator, Revised Edition 1938; United States Hydrographic Office; Not Copyrighted 1938.