1.  splashboard(n = noun.artifact) washboard - protective covering consisting of a broad plank along a gunwale to keep water from splashing over the side;
is a kind of protection, protective cover, protective covering
is a part of vessel, watercraft

2.  splashboard(n = noun.artifact) dashboard, splasher - protective covering consisting of a panel to protect people from the splashing water or mud etc.;
is a kind of protection, protective cover, protective covering
is a part of vehicle

   A guard in the front part of vehicle, to prevent splashing by a mud or water from the horse's heels; -- in the United States commonly called dashboard. [1913 Webster]