Most of Minnesota's 2.3 million boaters know they must remove their boat's drain plug after they tow their craft from the water to prevent the spread of aquatic invasive species.
And those plugs can't be reinstalled until a boater is readying to launch at a landing.
The problem is remembering to do that.
Some boaters have done so only after noticing water flooding into their boats.
"I've come close [to forgetting], and I've worried about it, but I haven't actually done it,'' said avid boater Jon Harkness of Maple Grove.
But the thought of accidentally sinking his 18-foot runabout got him ruminating. Harkness invented a device that he says is an almost foolproof way to store a boat plug and also remember to reinstall it.
"It just kind of came to me,'' he said. "I thought why not store it in a place where you also retain your kill switch tether, so you can't start your engine without remembering to put your plug in?''
The result: Plug Dock, a small plastic device that holds both the drain plug and the kill-switch tether. It's attached with adhesive to a conspicuous place on a boat.