here is how i finally remove the water from underneath the ski locker that some of us seems to have problem with. As you can see, it need to be vacuum dry again. I think water accumulate after its raining, my cover seems to leak at some place. another one is on the way.

Took a whole saw, drilled a hole, put a huge amount of marine goop. drop the plug on, let it dry, now when its full of water, i open it, suck it all up. done.