Here's what I have learned @ spar varnish-the hard way!

I finally have a finishs that look decent, after three weeks of frustration. What I have learned is to search this forum first, not after I screw up! My mistake, yup, a good brush and the right varnish make all the difference.
I started with Helmsman and poly foam brushes, and fine finish foam roller. I spent three weeks of applying finish, sanding off the awful runs and orange peel, going through three cans of finish, and completely heavily sanding the thing three seperate times. I tried thinning it, then thinning it some more, rubbing on, everything thing but what everyone said was the really right thing--good brush, good varnish. The final straw was what I though was the last coat came out high-low sheen, for no apparent reason. It was the last of my Helmsman. So I took a big breath and bucked up. Bought a can of Man-o-war varnish and a high quality expensive brush (after adding up all the foam brushes I through away after one use and 3 cans of Helmsman, it wasn't looking so expensive.)
So this am I put on what will be my final coat, no matter the result. And the results are good! I thinned it out @ 15% and got up at 6:00 am so it was not too hot yet. Whether it was the brush or the varnish, or more likely both, it went on like a dream, very few runs, spread out nicely, minimal brush strokes visable, uniform sheen, no orange peel (at least not yet). Yeah! finally! it is no spray finish, but I can live with it.
Lesson learned: buy high quality spar varnish, even if you have to drive 100 miles to get it (which I did) and a high quailty brush. You will regret it if you don't.
I started with Helmsman and poly foam brushes, and fine finish foam roller. I spent three weeks of applying finish, sanding off the awful runs and orange peel, going through three cans of finish, and completely heavily sanding the thing three seperate times. I tried thinning it, then thinning it some more, rubbing on, everything thing but what everyone said was the really right thing--good brush, good varnish. The final straw was what I though was the last coat came out high-low sheen, for no apparent reason. It was the last of my Helmsman. So I took a big breath and bucked up. Bought a can of Man-o-war varnish and a high quality expensive brush (after adding up all the foam brushes I through away after one use and 3 cans of Helmsman, it wasn't looking so expensive.)
So this am I put on what will be my final coat, no matter the result. And the results are good! I thinned it out @ 15% and got up at 6:00 am so it was not too hot yet. Whether it was the brush or the varnish, or more likely both, it went on like a dream, very few runs, spread out nicely, minimal brush strokes visable, uniform sheen, no orange peel (at least not yet). Yeah! finally! it is no spray finish, but I can live with it.
Lesson learned: buy high quality spar varnish, even if you have to drive 100 miles to get it (which I did) and a high quailty brush. You will regret it if you don't.