Vessel to put to sea (6)

I believe the answer is:

launch

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'vessel' is the definition.
(launch is a type of motorboat)

I cannot understand how the rest of the clue works.

(Other definitions for launch that I've seen before include "Send on course, ship or book" , "Establish" , "Send on its course, new ship or publication" , "Begin; motor boat" , "Send a vessel into water" .)

I've seen this clue in The Guardian and The Globe and Mail.

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