Check to board earlier vessel (8)
I believe the answer is:
schooner
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">vessel</span>' is the definition.<br/ ><span class="explanation-format__explanation">(type of ship)</span><br/ ><br/ >'<span class="explanation-format__original">check to board earlier</span>' is the wordplay.<br/ >'<span class="explanation-format__original">check</span>' becomes '<span class="explanation-format__intermediate">ch</span>' <span class="explanation-format__explanation">(abbreviation)</span>.<br/ >'<span class="explanation-format__original">to board</span>' indicates putting letters inside <span class="explanation-format__explanation">(inserted letters come on board)</span>.<br/ >'<span class="explanation-format__original">earlier</span>' becomes '<span class="explanation-format__intermediate">sooner</span>' <span class="explanation-format__explanation">(synonyms)</span>.<br/ >'<span class="explanation-format__intermediate">ch</span>' put within '<span class="explanation-format__intermediate">sooner</span>' is '<span class="explanation-format__answer">SCHOONER</span>'.<br/ ></span>
(Other definitions for schooner that I've seen before include "Two-master; a glass" , "Measure for sherry or kind of sailing ship" , "In the main it is" , "boat" , "Type of glass" .)