Conversation inspired me to go to the lake and check the Blue Tarp on the H14. I painstakingly added extra grommets, made a little tent over the tramp with two scraps sticks of pvc conduit (mast/s hang in garage), tied it off way low between the hulls so the snow would slide off. Been bitterly cold, plenty of snow, hadn't checked on it in over a month...it's TOAST, ripped right down the seam.

I bought a tramp cover that was touted to be "as good as" sunbrella...looked just like it. It disintegrated in three years, $50/year mistake

Remember the Billboard vinyl thread? Got my Vespa scooter sign for free. Made a cover for the H20, worked great, heavy material with UV coating on lettering side, bugger to put on and off.
IIRC that full size Billboard weighed 120 to 160 pounds, took two of us to load in my trunk.
Have half the billboard left, time to dig it out and make individual hull and tramp covers this time.