The purpose of using marine shrink wrap is two-fold:
Shrink wrap for boats
is to enclose boats to protect them from the elements when they are stored outside during the off-season. This is much cheaper than indoor boat storage.
Each of the above applications has a different method of installation of the shrink wrap. The only common denominator is that each uses a piece of boat shrink wrap
as the cover and a shrink wrap heat tool
to shrink it.
Marine shrink wrap is a low density polyethylene
(#4 LDPE for recycling purposes). What makes this shrink wrap film different than construction plastic sheeting is that it contains shrinking resins, UV inhibitors, anti-brittling compounds, and strengtheners, so that it will not rip or tear easily after being heat shrunk. Our supplier, Dr. Shrink, Inc., carries virgin resin premium shrink wrap. Please note that shrink wrap does not contain any flame retardant compounds (unless it is specifically labeled as flame retardant shrink wrap
). So, it is possible for shrink wrap to burn. Keep a fire extinguisher nearby at all times.
Steps in shrink wrapping a boat for outside storage
- Go around the boat to determine if there are any unusual features to the vessel. These would be outriggers, trolling motors, antennas, flimsy windshields etc. These items must be noted so they can be padded, or protected before the shrink wrap is laid over the boat.
- At the same time look for, and note, any damage that has already occurred to the boat. Owners may blame any imperfection on the shrink wrap crew.
- Whenever a boat is stored outside with a shrink wrap cover, it must have a support structure under the cover, with wooden uprights, to keep rain or snow from sitting on the shrink wrap cover and causing damage to the boat.
- The first step in building a support structure is to run woven cord strapping lengthwise on the boat from the highest point at the bow, such as the top of the rails or lifelines, to the highest point at the stern, which would be the stern rails or cleats on top of the toe rail. This strapping must be pulled extremely tight as it is the beginning of the support structure. Once this strap is pulled tight a tape measure is used to measure from the deck, directly behind the windshield in the cockpit, to the top of the windshield. 9" must be added to this figure and a 2 x 4 cut to this length (on wide beam boats you may need a taller 2 X 4). This will be one of the wooden uprights that will give the shrink wrap cover enough slope to shed rain or snow.
- This previously cut board from step 4 is then forced upright under the strap going lengthwise on the boat (be sure to use non-skid bottom support caps and puncture preventing top support caps). The board should end up vertically just behind the windshield in the cockpit. Now a strap must be run laterally (side to side) on the vessel so that it runs over the top of the 2 x 4 and makes a cross with the lengthwise strap. These can be tied to the top of the rails, cleats, trailer, or they can go around the entire boat. This strap must be pulled tight as it is part of the support structure and will help keep weight off the windshield.
- Once that is completed, the fore deck and cockpit are measured and wooden uprights (6" taller than where the fore and aft strap normally lies), are inserted under the strap. Again, a cross strap is run over the top of each of these boards. These uprights must be no farther than 7" apart. The number of uprights will vary depending on boat length.
- The tops and bottoms of each upright must be covered with non-skid bottom support caps and puncture preventing top support caps to keep them from protruding through the cover or having the base slip.
- This is now a good time to pad all sharp objects such as windshield corners, cleats, antenna bases, etc. TAPE THE FUEL VENTS AT THIS TIME! Call the boat builder if the vents cant be found. This is very important to eliminate explosions. Again, standard shrink wrap is not flame retardant. It can burn. Keep a fire extinguisher near you at all times.
Measuring to determine shrink wrap size and installing perimeter band
- A tape measure is used to measure from the top of the upright behind the windshield to however far down the side of the boat you wish to install the shrink wrap cover. This number is then doubled, plus you must also allow 6" of additional shrink wrap length on each side of the boat to tuck around and under the perimeter band going around the boat (we offer shrink wrap sizes from 12-50 feet wide).
The next step is to install a perimeter band around the boat, which is used to hold the shrink wrap on the boat. There are several methods of attaching this perimeter band around the boat.
- One is to run a rope/strap through the bow eye, around the boat, and through the two eyes on the stern of the boat. This rope/strap is then pulled tight.
- A second method is to tie loops, made of rope/strap, down from the cleats or stanchion bases to the level that you wish to cover the boat. These should be hung every 3-4 feet around the hull. The perimeter band is then run through these loops and pulled very tight.
- A third method is to tape the shrink wrap to the hull with hull/preservation tape, thereby eliminating any perimeter band at all. This is the most common way for boat builders to attach covers.
Installing the shrink wrap on the boat
- Once you have the shrink wrap support structure in place, all sharp objects padded, and the perimeter band attached (or if tape is going to be used in place of the perimeter band), the shrink wrap can be put on.
- The proper size shrink wrap is now put on a roller at the stern of the boat. Coming from the flat stern allows the shrink wrap to be pulled over the boat (this is much easier than coming from the bow). The shrink wrap is pulled over the boat, making sure that there is enough extra at the bow and stern to tuck around and under the perimeter band. This will help hold it in place in case the wind is blowing.
- After the shrink wrap has been pulled over, and tucked at the ends, the shrink wrap can be unfolded. There will be pleats of excess shrink wrap at the windshield corners, at the corners of the stern, and as the shrink wrap goes aft-ward from the bow. The pleats at the windshield must be folded to the rear of the boat, and tucked over and under the perimeter band, or taped in place if there is no perimeter band. This will assure that there is enough shrink wrap fore and aft, and side to side.
- Now the rest of the shrink wrap can be cut off 6" below the perimeter band (or just taped onto the boat if there is no perimeter band). Once this is done, all of the remaining shrink wrap material can be tucked around and under the band, or taped around the hull.
- After being tucked around and under the perimeter band, the Shrink wrap heat gun (heat tool) is used to apply heat directly above the band, which heat welds the outside of the shrink wrap to the piece tucked under the band. As you come to pleats or seams, these are heat welded at the same time.
- After the entire perimeter, pleats and seams have been welded (but before shrinking the upper sides and top of the shrink wrap cover), it is time to strap "belly bands" from the perimeter band under the boat to the perimeter band on the other side. These belly bands keep the shrink wrap cover and perimeter band from rising during the final stages of shrink wrapping. If these bands are not used, there is also a chance that snow or rain sitting on the cover could raise the perimeter band and allow the moisture to pool on the cover. This could cause tremendous amounts of damage to the boat.
Shrinking the boat cover
- So, once the belly bands are on, it is time to begin shrinking the entire shrink wrap cover. It is important to first shrink around the boat from the perimeter band, or taped line, to the rub rail on the boat. Using the shrink wrap heat gun (heat tool) is very similar to spray painting. The trigger is pulled as you move the heat back and forth, in a horizontal fashion, across the shrink wrap. You should begin at the lowest part of the cover and let the rising heat work for you to start warming the plastic. The ultimate goal is to have a tight top that will repel snow and rain, and this method will pull additional slack out of the top so that it will not take as much shrinking when you are ready for that area.
- The rest of the cover can be shrunk once you have completed heating up to the rub rail. Always start at one end of the boat and work in the same direction around the boat. This will give a tighter, more protective shrink wrap cover. Again, the ultimate goal is a tight, wrinkle free shrink wrap cover that will shed snow and ice
Hole patrol and shrink wrap venting
- It is very important to look over the entire shrink wrapped boat cover for holes, weak spots, or pleats that did not get heated enough. These should be taped with heat shrink tape / shrink wrap tape. Once the tape is applied it should be warmed slightly to heat the adhesives, and then rubbed to remove any air bubbles. If a hole is bigger than the shrink wrap tape that you have, then a piece of shrink wrap 2" to 3" bigger than the hole should be placed over the hole and taped around the entire edge area. Heat the tape with shrink wrap heat gun and then shrink the patch. The cover will perform as good as new.
The final step is to ventilate the shrink wrap cover with self adhesive shrink wrap vents. There should be anywhere from 3 to 10 vents attached to the most vertical surfaces around the boat. By putting the vents around the boat you are causing cross flow ventilation to occur. This will help eliminate any moisture and mildew buildup. How to specify the number of vents to use.