Where does “dark fleet” come from?

dark fleet (English) comes from English dark, from Middle English derk, from Old English deorc, from Proto-West Germanic derk, from Proto-Germanic derkaz, from Proto-Indo-European dʰerg-o-s, from Proto-Indo-European dʰerg-, from Proto-Indo-European dʰer- — to support; to hold.

Ancestry of “dark fleet”, step by step

dark fleet traces back through two separate lines of ancestry.

via English dark

StepLanguageWordMeaning
1EnglishdarkHaving an absolute or relative lack of light;...
2Middle Englishderkdark
3Old Englishdeorcdark
4Proto-West Germanicderkdirty; dark
5Proto-Germanicderkaz
6Proto-Indo-Europeandʰerg-o-s
7Proto-Indo-Europeandʰerg-to dim, darken; dim, dull; dark, dusky
8Proto-Indo-Europeandʰer-to support; to hold

via English Fleet

StepLanguageWordMeaning
1EnglishFleetA former prison (the Fleet Prison) in London, which originally stood near the stream
2Middle EnglishfleteA fleet; a collection or grouping of vessels; A...
3Old Englishflēotship; bay; fleet
4Frankishflotōnto float, swim
5Proto-Germanicflutōnąto float; drift
6Proto-Indo-Europeanplewd-to fly, flow, run
7Proto-Indo-Europeanplew-to fly, flow, run
Every word from Proto-Indo-European dʰer-