I am looking to buy a boat cover for my Sea Ray 185 sport. I have the snap on cover but would like to have another cover to put over it for protection when it is in the water and when it is stored in my yard. All I can find are covers that are for when you are pulling it on a trailer. I would like one that has a fits snug so it won't come off during a thunderstorm (when it is in water). Can anyone help????