How often should you apply 303 uv ?

I have to store my canoe outdoors (under tarp).

I was wondering how often I should apply 303 UV blocker?


never nm

It’s not what the poster wants to hear but I have to agree with you. The boat is stored outside covered with a tarp, so there’s no need to waste money on anything to protect the hull from sun damage. Not the best way to store a boat but I have one that’s out and covered by on old tarp I found along the road. It has never had any 303 used on it yet.

Apply it every time after you get your
boat wet.

Water is very, very bad for boats.

More Opinion
I’ve read that once and the beginning and once at the end of the season should do it. Applying it every time the boat gets wet sure would be a lot of work.

Not that I believe them, but the maker
says 303 should be re-applied when water no longer bead on the boat.

I don’t use 303 any more. I use a 3M yacht wax with UV inhibitors.

We do ours a couple of times a season
or more often then that even.

We have used it for the past six or seven years, but are thinking of switching to a car wax.

We have seen several that specifically say they have UV inhibitors and are good for fiberglass boats.

Jack L

The 303 folks argue that all UV
"inhibitors" are sacrificial, and are consumed as they do their job. They use this argument (which they do not prove) to support the idea that UV inhibitors in varnish (for example) will not last, so that one should use 303, and use it again whenever water no longer beads on the boat.

Now perhaps this is true, but proof is not offered. I expect that several layers of UV spar varnish may provide protection much longer than a coating of 303.

Or, just paint your boat with aluminum paint.

Scotchgard Marine Liquid Wax
Protects from UV rays. I used 303 for a short time when I first got my canoe, but it is expensive and water would stop beading on the hull after a few days’ paddling.

I bought a 500 ml container of Scotchgard a year ago, and haven’t quite used it all yet. Goes on easily, buffs to a really nice gloss, and the hull hasn’t faded at all in the Florida sun.

I coat mine
with sweat, tears and mud. I try to apply it several times a week.

I use it 2-3 times a year, and the hull
of my canoe still has some fading.

303 or it’s one of the one’s like it I apply about every couple months. Doesn’t take much btw.

Wax doesn’t work on poly btw.

Bill H.

I learned the hard way:
Don’t apply 303 to your neck gasket too often, or it will melt and turn to mush

when to use 303:
right before you sell a boat

Best response yet!

Thanks ,
that might be just what we have been looking for.

I’ll check and see if West Marine carries it.

Jack L

And why wouldn’t wax work on poly?

303 may very well be …
… one of those pseudo-scientific superstitions that Richard Feynman would call a cargo cult.

Nevertheless, I apply it once or twice a year.

The primary effect I notice is that after I apply it and put my boat on top of my van, it inevitably rains, upon which the 303 drips off the boat all over my van windows, from which it is very difficult to remove, especially when you are rarely motivated to clean the van.


– Last Updated: Jun-20-10 9:52 PM EST –

Buy a bottle.
Apply it to your canoe once a month.
The bottle should last at least 2 years.
If it does nothing; you have spent little.
If it helps; you have spent little.

You will not get 100% concensus regarding 303 here.
As a matter of fact; you will not get 100% concensus on virtually any subject here.

If doing something makes "you" happy; screw concensus.

Quoting the cook in Lonesome Dove .........
"I'll whack that bell if I want too"!


if you were replying to me, I did buy the wax at West Marine. They may have their own brand, too. I use their brand of biodegradable boat soap for my car and boat.

After almost a year in the Florida sun, I had to have a small gel coat repair done. Rob sent me the gel coat, and it still matched perfectly, so I know for certain the wax kept it from fading.