I used a tarp to cover my 20-foot catboat last winter and it was fine, even when the wind was whipping up above 30 knots. The tarp was old and had to be patched several times with duct tape as the winter wore on, but the boat came through fine. The spars were laid down lengthwise on cradles, helping to keep the air circulating between the tarp and boat. Considering the cost of shrinkwrap, I''m not sure why it is so popular at my marina, which charges $7 per foot for boats with 9 feet of beam or less. Add in the cost of hoops ($40) and a zipper door ($45), and the extra fee if the mast is not stepped (another $2/foot), and the shrinkwrap could cost me $265. Compared to $30 or so for a new tarp, shrinkwrap looks like a real luxury. There may be pros and cons I''m unaware of, but I''ll be using a tarp again this winter.