Naval forces (6)
I believe the answer is:
fleets
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">naval forces</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for fleets that I've seen before include "armadas" , "Groups of vehicles or vessels" .)