Preparing your Boat for the 2016 Storm Season
Sep 01, 2016 /
No matter where you’ve decided to keep your boat -- in a marina, at a dock, in a canal, hurricane hole or on a mooring, there are several additional points to consider: chafe, cleats and chocks, and windage. Hurricane-force winds exert tremendous strains on boat’s hardware.
- Wind force, and the damage it causes, increases exponentially. A doubling of wind speed increases the force on your boat four times. For example, a 20-knot wind exerts a force of 1.3 pounds per square foot; doubling the speed to 40 knots quadruples the pressure to 5.2 pounds per square foot.
- Chafe protectors are essential on all lines, wherever you keep your boat. Unprotected lines will chafe and sever within minutes under the rigorous conditions of a hurricane. Boats on a mooring are particularly vulnerable because the boat is usually held in place using only two pennants; the enormous forces generated are concentrated on only two lines.
- Depending on your boat, wave surge may increase loading by 1.5 times the values shown. These same forces are transmitted to the mooring; make sure all eye splices have thimbles to reduce wear at the attachment point on the mooring.
- Nylon line is well known for its ability to stretch under loads. Under severe loading, however, friction from stretching increases the internal temperature of the line to the point of meltdown. Heat from increased chafe accelerates the wearing process. Normal chafing gear is totally inadequate under hurricane conditions. Chafe protectors must be strong and longer.
- Remember, you’ll be using longer lines, increasing the percentage of stretch over a given distance. You can make your own protectors using heavy canvas (rubber or neoprene hose may cause trapped heat to melt line). If your chocks will accommodate two layers, add a second layer over the first. Heavy-duty canvas can be purchased through industrial vendors. Check with your local fire department or Coast Guard station-- they sometimes discard used fire hose, which can be fabricated into high-quality, low-wearing chafe protectors. Secure the chafe protectors to the docking lines. Canvas protectors can be sewn or tied to the line in a similar fashion.
- Lines should also be larger in diameter to resist chafe and excessive stretching. Generally you should use 1/2-inch line on boats up to 25 feet, 5/8-inch line for boats 25 to 34 feet and 3/4 to one-inch line for larger boats. Double up on critical lines. Use chafe gear wherever the line comes in contact with anything such as chocks, pulpits, pilings or trees.
- Longer, larger and more numerous lines will require larger cleats and chocks. In addition, the extra forces exerted during a hurricane will require stronger attachments of the cleats to the deck. Determine the size of lines you’ll be using and, if necessary, add bigger cleats to accommodate them.
- Beef up your dock cleats by adding backing plates if your boat doesn’t already have them -- unbacked cleats may pull out of the deck under heavy loads. Use stainless steel plates. Make sure you use the largest size screws that will fit through the mounting holes in the cleats. Use cleats with four mounting holes for added strength. Don’t overload a single cleat -- two lines per cleat should be the maximum. If your docking plan calls for more lines than there are cleats available, install additional cleats. Check windlass mounting points as well. The windlass should be mounted solidly with appropriately sized hardware and backing plates.