I sail an '85 Catalina 25.The ice box doesn't drain.Sliding my hand down the drain tube from the bottom of the ice box, I can feel the cold water in the hose all the way down to what might be the "drain hose shut-off valve". There is no cold water pass this "valve".Easy enough, just open the valve, right? Well, I can't get a good look at it, and there doesn't appear to be a handle that you can grab and turn.Is this a valve I'm unfamiliar with? Broken valve?Any advice would be appreciated!Ed