Douglas sea scale vs Douglas scale

Douglas sea scale and Douglas scale both are nouns.

Word	Noun	Adjective	Verb	Adverb
Douglas sea scale	Yes	No	No	No
Douglas scale	Yes	No	No	No

As nouns, Douglas sea scale and Douglas scale are synonyms defined as:

Douglas sea scale and Douglas scale: scale used for measuring the height of waves

Other synonyms of Douglas sea scale include international sea and swell scale.

Douglas sea scale (noun)	Douglas scale (noun)
scale used for measuring the height of waves	scale used for measuring the height of waves