If your boat has an extra drain plug fitting in the bilge you can use it as the water source for your ballast system using this 3/4" brass nipple. That means you don't have to drill any new holes in your boat below the water line when installing an automated ballast system, which is something everyone can appreciate.

Just remove the t-handle bilge plug, thread this fitting in its place, attach a bronze ball valve (see recommended accessories), and make your connection for the type of pump you're using.