I own a laundromat and have washed mine numerous times. It is the sumbrella material with the heavy plastic racheting straps. In does a great job. Make sure you use a 50# washer or bigger and choose the special wash or extended cycle to get all the dust out.
Dry it for 30 min then take it out and turn it. Reload for another 30 or so. You should be able to do it for $7-10. Tip the attendant $5 and have them transfer it to the dryer and turn it for you.
If concerned about the rachets clacking around tie an old sock around it.
These are boat covers boys, not your Gma's heirloom quilt ya know.