I got this nice custom made canvas boat cover with my boat and I thought it would be good for wet weather but it doesn't seem to be waterproof.

Is this thing really only meant to keep sun off of it or is it supposed to be waterproof?

Is it going to do more damage.....not allowing the boat to dry?

Thanks.

Since you have a canvas cover and not a vinyl cover, the water repellant chemicals eventually wears off the canvas.

I have always had to treat mine with scotchguard periodically to keep it waterproof. Takes about 3 spray cans to do the cockpit cover and about 6 to do the full boat cover. I once had an old salty guy tell me that Thompsons water seal (the stuff they advertise for decks and concrete) works the best. Just roll or brush it on. I've never been brave enough to try that one.

I purchased a gallon of water proofing from the canvas shop that lined my cockpit cover with fleece so it wouldn't scratch my new paint.
I mixed it per the instructions and sprayed it with a weed sprayer.
My cover is sunbrella material and it is 100% water proof now!!

I had asked the canvas shop to spray it but they declined due to the fumes it produced in their shop.

I took it to my shop and turned on the exhaust fan for about 24 hours till it dried.

I've used Thompsons water seal on my canvas boat for years.
it works great. spray it until the cover is just damp with a garden sprayer when it's not gonna rain for a day or so.usually lasts for the whole season.

btw you probally don't want to use the tinted thompsons.

Don't use Starbrite Waterproofing with Teflon, I used it this summer and it doesn't work too good. Starbrite makes great products, but I'm not impressed with this one.

I'm curious about using the Thompsons water seal. Any one else using it? Anybody had any problems or bad results?

if you use thompsons on the cover while it's on the boat don't saturate it or it'll be on the boat. just spray til lightly damp

Sunbrella recomends 303 protectant, works great.

Sunbrella recommends 303 Fabric Guard Waterproofing, 303 Protectant is for the Vinyl Upholstery

You got that right. Im try Thompson next.