The crossword solution for the term 'rowboat seat' is 'THWART, ' which is a six-letter word. A THWART is a structural member of a boat that runs across the width of the vessel, usually near the middle, and provides support for the seats. It also helps to keep the boat from flexing too much when it is in the water. The THWART is an important part of a rowboat, as it provides a stable platform for the rower to sit on while rowing.