light waterline

• light water line

From light (“lacking weight”, adjective) +‎ waterline (noun).

light waterline (plural light waterlines)

1. (nautical) The waterline at which a vessel floats when light or unladen.

• light line (noun)

• deep waterline (noun)
• light displacement (noun)
• load waterline (noun)

• William Dwight Whitney and Benjamin E[li] Smith, editors (1914), “water-line”, in The Century Dictionary: An Encyclopedic Lexicon of the English Language, revised edition, volumes V (Simular–Z), New York, N.Y.: The Century Co., →OCLC, section 6844.