Watery Measure of Six Feet
Puzzle 4 of Making Sushi Pack
Question is: Watery Measure of Six Feet
and the answer is: FATHOM
Word Meaning:
FATHOM — (chiefly nautical, historical, US) A man's armspan, generally reckoned to be six feet (about 1.8 metres). Later used to measure the depth of water, but now generally replaced by the metre outside American usage.
Definitions from Wiktionary.