It is prudent to remove the bailer bungs when in the boat park, also to adjust the height of the nose wheel to ensure that the boat is completely level and any water leaking through the cover is able to drain away via the bailers. Check the set of the canvas to avoid water pooling on the cover. When set up correctly the boat will remain completely dry even through periods of heavy rain.
The original cover has its weaknesses. It has a lifetime of approx. 5yrs before signs of deterioration begin to appear. The threads securing the zip start to rot and the Velcro loop material adjacent to the hoop also rots and tears even with careful use. A further weakness is the design for sealing around the hoop. Water can enter the boat around the hoop if the canvas sags. A better design than the current arrangements would be a full zip over the hoop or better still an overboom design that would avoid any tendency for the covering to sag and trap water.