That's why I put four ratchet straps under the tarp at assumed load positions. These were to prevent sag at strategic points *IF* snow loads became too great. Another point is to see to it that the hull is bow-high to keep water drained to the scuppers.
Oh yes! A barn *is* nice...if ya have one handy
I've looked at the "portable garages" like the tent and frame that FS linked. Waaay too much $$ for the expected coverage... even on our side of the pond... and then there's the issue of permission and mounting!?