Just a note, for those that don't know about the Coastline covers, they have a soft material on the back of the cover. Keeping a good wax on the car allows for the cover to move without scratching the paint.
The cover wraps all the way under the front and around the front fenders and up to the windshield. I've never had rocks or sand get under the cover as it would be rather difficult.
The cover can also be washed in a washing machine (most likely the large type of unit at a Laundromat) but I've never done it as I keep it clean.
MM.