We'd been trying to invent some means of making a cover for the air cooling vent so that when the rain was horizontal (or bouncing off the cabin top) it wouldn't run down inside the trunking. And to no avail - although I have since seen a boat with a specially made wooden box that goes over the top. Then Jim came back from a Lifeboat event with two reflective rucksack covers, intended to make cyclists more visible (hence they are emblazened 'East Sussex Fire and Rescue'). Right size, strong elastic, and even a securing strap to go underneath. Perfect. Now all we need to do is find and seal the leak where the water seeps under the flange.