In the regulations that apply to small passenger vessels an "open boat" is a vessel __________.

Correct Answer: Option C — that is not protected from entry of water by means of a complete weathertight deck

Per 46 CFR 114.400, an open boat is defined by its lack of a complete weathertight deck. This structural configuration leaves the vessel vulnerable to water ingress from seas or precipitation, necessitating specific safety requirements regarding buoyancy and stability that differ from fully decked vessels.