I found that a cloth cover deteriorates easily when the boat is stored at my home. Tree limbs pierce the cover. Animals pierce the cover and eat it selectively. Leaves and debris (and snow) build up and cause the cover to rip and tear.
Keeping the water out:
I have been thinking of making a cover out of corrugated polycarbonate roofing and putting bracing that is not attached under the material for strength but allowing removal and storage when the boat is being used as a sailboat. My wife objects to the boat as "an unsightly lawn ornament" when it has tarps and wood bracing in our yard. The cover should be easy to remove, disassemble and store as well as assemble with few parts and tools. Both a garage and a shed are out of the question.
Getting the water out:
When water comes into the boat from rain or snow, the small 0.5 inch drain clogs easily. I've considered cutting holes in the transom and putting in bungee straps to keep flaps in place but that compromises both the boat hull design and opens the boat to other perils (plus where to attach the bungees). I want the boat to self-empty with no electricity of human attention.
I have owned my Day Sailer 1 for over 40 years, I had 15 years of use initially and then put it aside. (I currently sail a Cal 24 on the Hudson River). Now, thinking of using a newly restored Day Sailer 1 for pleasure on light air days, I want to keep the boat clean and dry. I do not want to buy a cloth sail cover but want to have an easily-removed, weather and varmint-resistant cover. Surely there are others who have similar needs. The Day Sailer 1 is not designed to drain out or to leave the cockpit uncovered. What have others done that they are willing to share? Newer Day Sailers probably want to keep the sun and debris out too but their design does let the water out.