I use a small fluid extractor for hard to reach spots I want dry. Bought this one recently, happy with it so far.

Yes, as FF mentioned, the middle plug on transom drains the area between the liner and hull. Audio, if there's substantial water draining from there at year end, I'd be concerned how it's getting there because there shouldn't be a lot. Only place that I know of where water can get into that area under normal conditions is from the bilge factory inspection holes.