Treat mooring cover with 303 water repellent

[Pontoon3003]

Just bought a used 2020 23SX. Mooring cover in good shape but needed washing badly. Also it allowed water through to seats prior to my purchase. Mildew stains on seats- (clean that up next project). Washed cover in & out sides with 303 Multi Surface Cleaner. Now want to apply 303 Water Repellent after it dries throughly.

Question- should I install the cover on the boat or treat in under my carport where I washed it?

Input appreciated

2020 23SX, Yamaha 115 4 Stroke, Con-Fab Tandem Axle Galvanized Trailer (My 2nd Bennington Pontoon Boat)

 

[Jack M]

Do it in your carport. You will have a real mess when it runs down your side panels

 

[SEMPERFI8387]

Plus it can damage seats if you apply on the boat. Happened on my last one. Just a note, they are NOT water proof. They WILL allow some water through, especially where they touch the seats. 303 acts more like wax and makes water bead and run off easier.

 

[BigKahuna]

I laid mine out in our garage. Sprayed it with water repellent then let it dry. Sprayed it again to get the areas I may have missed. Let it dry......

 

[Pontoon3003]

All good input! Thank you!!
Since not “waterproof” should I put something waterproof (Harbor Frght tarp) between the seats and the cover? My concern is further mildew/staining where the cover rests on the seats. Never used the cover on my previous Bennie. It was stored inside- shop now full of tooling.
Again thanks for the advice
DD

 

[BigD]

All good input! Thank you!!
Since not “waterproof” should I put something waterproof (Harbor Frght tarp) between the seats and the cover? My concern is further mildew/staining where the cover rests on the seats. Never used the cover on my previous Bennie. It was stored inside- shop now full of tooling.
Again thanks for the advice
DD

For what it's worth. I waterproofed my cover with Starbrite, and for the 6 months mine sat outside with the cover on it, it never got a drop of water under the cover. My cover has 4 vents, so ventilation was never a problem either. But I don't cover mine at all since fall of 22. It's in a fully enclosed steel building built just for it.

 

[sunedog]

For what it's worth. I waterproofed my cover with Starbrite, and for the 6 months mine sat outside with the cover on it, it never got a drop of water under the cover. My cover has 4 vents, so ventilation was never a problem either. But I don't cover mine at all since fall of 22. It's in a fully enclosed steel building built just for it.

I've used both the 303 Fabric Guard water repellent and the Starbrite Waterproofing. While I love the 303 Aerospace Protectant for vinyl seats, the Starbrite Waterproofing outperforms the 303 Fabric Guard.