Chafe Protection

Chafe Protection in Storms I un Ili t Member in Miell Ilk Highlands. New Jersey. wrote .Moue wan awhile ago about a near cata- stroithe he emx•nenced with chafe on his -JO' sailboat's mooring line. A gale had swept through the area with 55.mph winds, sinking seven boats at his Atlantic High- lands Yacht Club and beaching eight others. In all but one of the losses, the cause was a laded mooring pennant. Chip's boat survised, but barely. He'd used two :VI" nylon pennants, each three months old, with two feet of clear PVC tub- ing to guard against chafe. When the winds let up briefly. he motored out to the boat to inspect the fines: 1 went pale. Both plastic host% had smite sheers cracks and both lines had chafing failure inside the hoses. Iwo art the three main strands were worn through turd cud) u few mini strands of the dent weir still holding If the winds had hosted another d0 IlfintileS, my boat would lune been an the rocks' the letter. with one of Chip's chafed pen- Hams enclosed. sat around the Seaworthy naives lin stiany months, nal because the topic isn't important—it is extremely impor- tant—but because answers have been so elusive. Nylon, because it stretches and absorbs shock, has been the line of choice lot mooring pennants. And a lot of experi- Piteed professionals once thought whitened PVC tubing was the answer to chafe; it is Ilexibt rugged. and comes in ail xnl ,un ler Nth. With each passing north- ,•astei. honest% it I wcaine apparent that nylon and PVC are vulnerable in a storm, mow vubwrable than other types vl line and chafe protection. Huainan Klopman. a marine surveyor in Marblehead. Massachusetts. sent Seatuor- tin ,minter chilled nylint pennant that had been "protected" lry PVC tubing until it part- ed in a northeaster. PVC, he said, might be t K (or nxilinv chafe in mild weather, but it is clearly vulnerable in a storm. Learning from Past Hurricanes After hundreds of boats dragged their moor- it lg. ashore in Hurricanes Gloria and Bob. many harbormasters replaced their mush- Mull and deaths-eight moorings with helix alit hills which tun be screwed deep into the bottom of the harbor. Helix anchors have proven, over and over, that they have far greater holding power than anchors that sit on or near the surface (Seaworthy, July 1993). Another Innovation, the Hazelette pennant, was developed to absorb shock and reduce a boat's sailing back and forth on its pennant. The Hazelette, which is meant to be used with longer conventional pennants in a storm, absorbs shock and reduces wear on the fittings, mooring anchor, and lines (Seaworthy, October 1996). As (or chafe, the two massive hurricanes also prompted the Massachusetts Institute of Technology to do a study—"Wear and Fatigue of Nylon and Polyester Mooring Lines"—on why pennants fail. While the study didn't recommend any specific type of chafe protection, it did gives clues, valu- able clues, as .to what could be done to reduce mooring line failures. Some of what the study found: • Under heavy loads, the constant cycling— stretching and contracting—builds up heat, due to the frictional interaction between yarns. The line wears internally. rhis is especially true of nylon, which can stretch to about 40% of its length vs. only 8% for polyester (Dacron)1 • Polyester Is more abrasion-resistant than nylon under heavy cycling loads. When the polyester and nylon rodes are wet, the dif- ference in abrasion resistance is even greater. • Under heavy cycling loads, wet nylon yarn is more abrasion-resistant than dry nylon. Under light loads, the reverse is true—dry nylon yarn outlasts wet nylon. Heat builds up because of friction between the fibers and also because of internal mol- ecular friction. In a storm, then, wet nylon would last longer than dry nylon because the water would provide additional lubricity (good marine nylon line typically already has a finish that helps to reduce yarn-on- One of Chip Del Ciiro's tors were starting to split, but the line failed internally from hen. lack of external abrasion on the liney yarn friction) as wen as coos the sky...-. fibers. When examined closely. tlw failed rn lei pennant sent to Sewtonln In Chip lie Coro had small welds—Windy lumps—.:- the ends of wine ul the tailed ',hands which indicated that the law had tail..: internally. Funherinow. me broken showed no signs of emernof that had become -turty- over a wide are.: after mbbing against the chock. Stine). Klupman also noted that with hues examined that had failed inch' were typically ••nticro welds" ad the ends • • the failed strands. PVC: A TI ivory Could it be that PVC. bv keeping the lie, dry and providing insulation to roam hr.,: in a storm. hastens the . nylon line it is supposed "It sounds mason:dile." say. Sklit.t. Backer. one of the authors at the study. One of Backer's associates. \tn . Duelling, itte former Assisuan bare. MIT Sea Grant. says Ow saner P. increases the eller:Ilse bendaiN roam, the chock, which has the brnelil reducing heat, but he too worries that long run of PVC tubing might also ploy:: water from reaching the stressed mi. fibers. Both Backer and Doe lling Nut's's. NJ:L c-a., that the best way lo assure a line won : is to use polyester rather than 111111.11t the deck cleat out past the chuck isys- next page). This provides increased protection on deck while also prcivida.. elasticity to absorb shock (Duelling. ts:,‘ keeps his 38' sailboat on a mooring. sa.• that chocks with sharp edges should .i.s, be replaced with rounded shocks ) 6 SN7wOrrity Jury. UN,. EFTA01089549 Polyester line may be more chafe-resistant than nylon but tests have found that It too builds up heat. although far less heal than nylon, and is subject to internal as well as external chafe under heavier storm loads. Is there a material that pro- tects the line from abrasion while also keeping II cool Internally? Seaworthy called several boatyards to see what was being used. Some are still using PVC while others have returned to leather, even though leather chafe protection had often failed during Gloria and Bob (Seaworthy, July 1992). Jono Billings. who owns a boatyard in Jamestown. Rhode Island, says he has been using a canvas-like tubing made by Perimeter Marine Products to protect the outside of the line from abrasion. Billings said he's never had a line fail that was pro- tected with the material, and that Includes lines that have been through some strong northeasters. Aside from protecting the line from external chafe, the material wicks water, which helps reduce heal buildup inside the line. And what Is this newfangled chafe protection made of? Polyester, the same material that the MIT tests found is resistant to chafe. A Simple, Inexpensive Method forOk Strengthening Mooring Pennants A simple way of providing durability is to make up41?i of polyester line the same diameter as your eats,, line. According to Norm Doelling (Seaworthy, ARth should be at least six feet long and can usually ' feet long. Make an eye splice, leaving a large eye about sure to have at least five, and preferably t splice. The polyester line can be passed ing nylon line in an eye-to-eye fashion,a,s; illustration. This gives a dock or tures of both types of ropes—nylon' abrasion resistance. . Doelling said he keeps two p stowed aboard his boat so that or ready to go, should they be,needed.!. Will the Boat Be There After the Storm? The strain on a line in a storm can be severe, almost beyond comprehension. Joe Schorle, a BOAT/U.S. Member in New Jersey watched the bow of his 38' sailboat being tossed high in the air by an especially fierce northeaster that came through the area two years ago. The boat survived the storm, a feat he attributes more to a redun- dancy in lines—he used four, $8" braided nylon lines—than to the short pieces of rubber tubing he used for chafe pro- tection. '1Wo of the lines that were used had been reduced to a few strands and two remained intact. He too has since changed to the polyester Perimeter chafe protectors, which he feels will do a better job of protecting lines. Chafe at a Dock Chafe can occur anytime. anywhere. even when the weather has been fair and the boat is kept in a well protected slip. %%liter. This Wisconsin boat which was protected from Lake Michigan only by a bridge, had its mooring line chafe through alter being rocked by a late season storm. The line didn't appear to have any chafe protection. Note the distance from the boars port side to the outer piling. Longer nylon docklines stretch more and can be more vulnerable in a storm (Claim /9708587A). While there are certainly no guarantees in a storm, the Idea of redundancy, using three or four mooring lines, is a technique that has been used success- fully by skippers for centuries. And MIT's research makes a strong argument for using poly- ester lines from the cleat through the chock to reduce abrasion failure. As for protecting the polyester lines from chafe, using the same material—polyester--is a promising solution. Will all of the lessons learned in Gloria and Bob mean that boats will be better protected in the next category three or four hurricane? As one harbormaster said, "Whenever we've had a bad storm up here, we've always found out what doesn't work." With the introduction of the helix mooring, ilazelette pennant, better chafe protection, combi- nation nylon/polyester bridles, as well as more and larger lines, it could be that after the next hur- ricane we may finally get a better idea of what works. wind, and tide will keep the boat in con- stant motion, which means a line that rubs against a metal stanchion or chuck, even slightly, day after day, week after week. will be vulnerable to external abrasion. Salt crystals and din in the fibers accelerate wear, but any line that rubs against a hard surface—metal, wood, or fiberglass—will chafe if it isn't protected. With most docklines. a shod piece of chafe protection at potential trouble spots will prevent abrasion and keep the line healthy. Three things that may warrant using polyester line from the cleat to the chock and/or adding beefed-up chafe pro. tection on a dockline: longer runs of line. over about 12'; lines that pass over sharp angles; and boats that are kept in slips that aren't well sheltered. The longer the line, the more its. •ill stretch. which builds up additional heat and increases its vulnerability at chafe points. typically a chock. A line attached to a cleat that is several feet away from the chock is more vulnerable than a line that is secured next to a chock. When the line passes over the chafe point at a sharp angle, it is even more vulnerable. And if the boat Is kept at an exposed location, the probability of a line failing is that much greater. A boat In Wisconsin (above), for example. kept at a slip that was protected from Lake Michigan by a bridge, had its mooring line chafe through after being rucked b) a late season storm. The line didn't appear to have any chafe protection (Claim 41970358M). II Seaworthy Jury 2990 7 EFTA01089550