Winter Boat Cover vs Shrink Wrap: Support, Ventilation, Safety and Spring Removal

Measure centerline length from the bow to the farthest point aft you'll cover, and the widest beam, as BoatUS describes. Go over windshields, consoles, T-tops, rails and outboards if the cover isn't made for your exact boat. Note anything that sticks up or out (antennas, rod holders, radar). Write it all in BoatMend so next year is easy.

Snow and rain are heavy. A flat cover pools water, stretches, rips at seams and can load the boat, trailer or lift beyond what they're built for. Build a ridge that runs bow to stern, high enough that the cover slopes clearly down and over the sides, with cross-supports so there are no flat or low spots.

• Use lumber, PVC or aluminum poles, or the cover maker's support system. In BoatUS Foundation tests the poles that came with covers often weren't strong enough and needed extra strapping and poles.
• Pad the top and bottom of every pole (carpet squares work) so it doesn't punch through the cover or dent the deck, and put non-skid under the pole bases.
• In heavy snow areas, make the pitch steeper and the frame stronger.

Cover windshield frames, rail ends, cleats, antenna mounts, rod holders and the outboard's corners with pool noodles, foam or towels. Covers and shrink film chafe through at these points over a winter, and the padding also protects your gelcoat.

Boats need to breathe under a cover. Without airflow you get condensation, mildew and odor by spring.

• Fabric covers: choose one with vents, or add them, and position them high and at opposite ends so air can move through.
• Shrink wrap: add several self-adhesive vents, high on the sides and at both ends. More is better than fewer.
• Leave locker lids and hatches cracked open inside the boat where weather protection allows.

Start at the bow and roll the cover aft, as the BoatUS Foundation team did. Hook the bow first, then work out wrinkles as you go back, cinching side straps to pull out low spots. Run straps under the hull or trailer, never to jack stands: BoatUS warns that in wind or under snow load the tension can pull the stands out from under the boat. Label the bow and stern on the cover and mark the centerline for next year.

If your yard allows it and you decide to DIY:

• Get a heat tool made for shrink wrap, read its manual, and practice on a small piece first. Use flame-retardant film if you can get it.
• Work only on a calm day, outdoors, with a helper whose only job is to watch for fire and hold the extinguisher.
• Make sure there's no fuel smell anywhere in or near the boat, portable fuel tanks are off the boat, and nothing flammable is stored under the cover. Keep the propane tank and hose away from the heat.
• Keep the heat moving and well back from the film. Never hold it on one spot, and never aim it at people, hoses, fuel fills or wiring.
• Don't reach under or inside the wrap while heating.
• After you finish, walk around the boat for a while and look for smoke or glowing spots before you leave.

Typical sequence: install the frame and padding, run a perimeter band (strapping) around the hull below the rub rail, drape the film, tuck and heat-weld it to the band, then shrink the top and sides evenly. Add vents and a zippered door after shrinking, on film that is already warm. Tape any holes with shrink wrap tape.

Thicker film handles more snow and wind. Ask your supplier which thickness they recommend for your snow load and boat size, and use film made for boat wrapping. Don't use thin plastic sheeting or painter's plastic.

BoatUS suggests checking at least once a month and after every heavy snow or rain. Look for:

• Pooled water or snow building up (knock snow off gently from the ground with a soft broom; don't climb on)
• Straps that loosened or are now carrying the weight of pooled water
• Chafe spots, tears and rips (tape shrink wrap holes right away)
• Signs of animals getting in
• Mildew smell when you open the door or lift the cover

Wait for a dry day. For a fabric cover, sweep or hose off dirt first, remove it bow first, clean it as the maker says and let it dry completely before folding.

For shrink wrap:

1. Cut the bands under the hull first (the straps under the keel).
2. Cut the film into pieces you can handle, cutting away from the boat and with a safety hook knife so you don't scratch the gelcoat.
3. Remove all strapping, buckles, vents, zipper doors and tape. Keep the film clean, dry and free of dirt and stones.
4. Roll or fold the film loosely.

Shrink wrap is low-density polyethylene and doesn't break down in a landfill. Many marinas collect it in spring. If yours doesn't, check your county or state's clean marina program, or use a mail-back bag from a shrink wrap supplier (BoatUS Foundation points to this option). Recyclers want it clean, dry and stripped of all straps, vents and zippers.

Open every hatch and locker and let the boat air out. Look for mildew, water stains, rodent signs and chafe marks on gelcoat where the frame or straps rested. Clean anything you find before it spreads. Then move on to your spring recommissioning.

Number or label frame pieces and take photos of how they went together. BoatUS has a reader story on reusing the same shrink wrap for several years by careful removal; it takes care and space, but it's possible. Store covers dry and away from rodents.