Winter cover

For years I've put a tarp on my pontoon, pulled over a tall pvc ridge pipe so it's too steep for snow to stick. I don't know if my 18' bowrider needs the same. I have the canvas snap covers & support poles for the interior, and a nylon storage cover. Is that enough?

If you're in an area that gets heavy snow please chime in with what works. EXCEPT shrink wrap. I know that's effective but I'm looking for a diy solution.