Apparently your mileage may vary on this product. As a waterproof boat cover it didn't work for me. Water simply permeates the fabric and drips into the boat.
In addition, the fabric doesn't 'breathe' so water got and in the lack of airflow overtime created a mold that covered most of the inside of the boat. The varnish on my boat deck failed (I think) because the wet fabric was constantly in contact with it.
Because of all the tie-downs it comes with, It works reasonably well as a cover for the plastic tarp that is keeping my boat dry...
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Perhaps a more important issue for me is that I have been trying to leave this review on the DuraShield web site (there are currently 4 reviews there for this item, all 5-star), however their system states that the review has been recieved and will be going through 'moderation'. Apparently it never makes it out of moderation. I have left the above review twice. Any company that will not display fair but unfavorable reviews is not a company that I would ever do business with again. If you feel like I do, then I advise you to stay away from this product and this company.