Buoyancy Structure Attached to Side of Boat

This page is the CodyCross answer for the clue below from Medieval Times, Group 235, Puzzle 3 (Rollo the Viking).

Question is: Buoyancy Structure Attached to Side of Boat

and the answer is: OUTRIGGER

Word Meaning:

OUTRIGGER — (nautical) Any of various projecting beams or spars that provide support for a sailing ship's mast.

Definitions from Wiktionary.