Sloop's spine (4)
I believe the answer is:
keel
(Other definitions for keel that I've seen before include "Ship's basic longitudinal structure" , "Lengthwise structure of a ship" , "Ship's bottom" , "Support on which ship is built" , "ridge" .)
I believe the answer is:
keel
(Other definitions for keel that I've seen before include "Ship's basic longitudinal structure" , "Lengthwise structure of a ship" , "Ship's bottom" , "Support on which ship is built" , "ridge" .)