September 2003 Issue
Securing At The Dock
As we approach hurricane season, I would like to add a few observations toNick Nicholson's timely article, "Fit to be Tied" [July 1] about securing boats at a dock. Based on our BoatU.S. insurance claim files, nylon lines often fail internally during a storm. Nylon stretches up to 40% of its length (vs. 8% for polyester). Under heavy loads, the constant cycling—stretching and contracting—creates tremendous heat due to frictional interaction between yarns. A line that has failed internally will have small lumps of melted nylon at the ends of the broken strands. These lines typically show no sign of external failure—fuzzy yarns over a wide area after rubbing against a chock.
One predictor of potential heat build-up (and failure) is the distancebetween the cleat and chock: the greater the distance, the more the linewill be stretched as it works back and forth across the chock. The secondpredictor is the angle from the chock to the dock cleat or mooring ball. Thesharper the angle, the more heat that will be generated. The ideal remedyfor this, found on many newer sailboats, is to locate cleats at the rail sothat a chock is no longer necessary.
The other remedy is better chafe protection. An important observation on nylon line (based on a study by MIT Sea Grant, "Wear and Tear of Nylon and Polyester Mooring Lines"): Under light loads, dry nylon outlasts wet nylon. Under heavy cycling loads, the reverse is true—wet nylon yarn is more abrasion-resistant than dry nylon. Water provides additional lubricity to the strained nylon fibers. This is one reason that lines protected with (healthy) PVC tubing are likely to fail in storms—long lengths of tubing will be keeping the line dry.
Several years ago, I called marina owners and harbormasters to see what type of chafe protection they recommended. There was no consensus, ofcourse, but one New England marina owner noted that he had been usingpolyester tubing for several years to protect boats on moorings and, despite several intense storms, had never had a line fail. That's not surprising. The MIT study found that polyester is more abrasion resistant than nylonunder heavy cycling loads. When the polyester and nylon lines are wet, thedifference in abrasion resistance is even greater. One other plus is thatthe polyester sleeves wick water, which further protects the nylon internally.
Norm Doelling, the former Assistant Director of MIT Sea Grant, went a step further. He devised a technique using polyester line from the cleat through the chock that is then attached to a nylon line that is extended to the dock cleat or mooring ball. Rather than joining the two lines with knots, Doelling uses loops spliced at the ends that are then looped together in an eye-to-eye fashion. The polyester line provides protection from chafe while the nylon line absorbs shock. He used the set-up on his 38' Hinckley inMarion Harbor.
BoatU.S. Marine Insurance Publication
Good article and needed reminder to all. But...I have had a boat during the season at Miami Beach Marina, towards the south end, for about 15 years. There is almost constant wave action from Government Cut andfrom passing traffic. The after-effects of a major North Atlantic storm resulted in breaking waves in the marina. The dock is concrete, short and is supplemented with four pilings, two stern and two midship, limiting tie points.
My best solution has been reinforced plastic hose—the kind usedfor pressurized water. The solution to positioning is to use oversize lengths, in some cases long enough to pass around the cleat. In fact, the combination of concrete dock and cast cleats mandates that at least the first turn requires chafe protection.
I have been able to get three to four years from a single piece of hose, so ultraviolet degradation is not a problem.
I have tried leather and canvas chafe guards. They wear out and shift. At the key southeast and west corners of my boat, I use winches as I feel that they can carry a larger load than a heavy, well-mounted deck cleat.
Knock wood, neither of my boats (Fisher 34; 22,000 lbs. and Cheoy Lee PHMS; 34,000 lbs.) has suffered damage. I also use a spider web of lines—four bow, two forward springs,one after spring, and four stern lines.
Three-Legged Rope Mooring
The item "Rope Instead of Chain?" in PS Advisor, June 2003, caught my attention. As I have moored my boat continuously since August 1995, my experience may be helpful. I will try to be brief.
Economics was the driver in using this mooring system, but closely behind that was my belief that sailboats are not designed to suffer the bump and grind of being hog-tied to a dock. But in taking this approach I would only warn that I don't see favorable economics in going on the cheap with an expensive boat hanging on the pendant. The marine environment is rough and the only answer is the old Maine proverb, "Nothing too strong ever broke!" For me, that means redundancy.
Location and Local Conditions: Days after purchasing my 1978 San Juan 28 I deployed a three-legged mooring system on the north side of Raft Island in Henderson Bay in South Puget Sound, Washington. The prevailing winds are from the southwest except for strong Canadian northerlies during January and February. The tidal current is roughly 1/2 knot maximum, with a range of -3.8' to +15'. The bottom is mud. The west and east leg anchors, running along the shoreline, are deployed in 10' of water at zero tide. The north leg was deployed in 66 feet of water, and the boat was allowed to idle forward to remove all slack from the system before this final anchor was released over the side. The buoy rests in 30' of water at zero tide, about 125 yards off the island's shoreline.
The Mooring Rig: From anchors to buoy, each of the legs currently consists of a Danforth S1600 anchor (the original Danforth S2000 remains on the east leg), 8' of 3/8" chain, and 300' of 1/2" three-strand nylon. All three legs are bridled onto a single 8' x 3/8" chain, which runs up through a 1/2" eye & eye swivel, and then to 2' x 3/8" chain running through a Taylor 24" (#46374) buoy with 240 lbs. buoyancy, and a 4" ring. All metal is galvanized, and all shackles are 7/16". (Boat/US insurance was happy about the use of 3/8" chain.) Plastic cables ties are used on all shackles pins and nylon line ends. Two 1/2" braided nylon pendants are used, and securely "knotted" to the bridle swivel via a 5/8" shackle. This 5/8" shackle was necessary due to the space required for the line knots.
The pendants are prevented from wrapping around the bridle during tidal changes by a four foot wooden 2x2 strapped to the pendants at the buoy with shock cord. This provides a standoff distance from the buoy and leverage in turning the swivel.
The system was initially inspected annually to assess component wear. Maintenance consisted of winching up the buoy and bridle via a snap shackle off the bow pulpit. (Additional support to the pulpit was provided by the spinnaker halyard.) Items were replaced as required. Annual inspections ceased after the first leg failure, as enough experience was acquired for system management. Maintenance and repairs are now completed only upon a leg failure or every three years, whichever comes first.
Lessons Learned: The first thing I learned was to use the largest size shackle possible commensurate with the system; a 3/8" shackle would last only one year. I am now using 7/16" shackles, the largest possible, on 3/8" chain. The weakest point on a shackle is the threaded area, so the pin must be secured. I recommend plastic cable ties rather than galvanized wire, which will be eaten through in less than a year.
The mooring system has had three legs fail since initial deployment; twice on the north leg and once on the west leg. (These are the legs experiencing the greatest wind pressure.) The East leg remains on the initial rig (7.8 years). After each failure I inspect the system to determine what failed and make adjustments. Significantly, all three failures occurred at the bridle where most of the system movement (chafe) takes place. Two of the three failures occurred because of nylon eye splice failure and once due to a shackle failure. In lieu of an eye splice I now use a Fisherman's Bend, also called an Anchor Bend, and cable tie the end for good measure. I have not experienced this type failure thus far.
A few other tidbits I have learned include the importance of using galvanized thimbles rather than nylon; I have found some nylon thimbles worn more than 50% through. Additionally, I was taken by surprise at the rapid marine growth that accumulated on the legs after just two years. The initial buoy (18" with 90 lbs. buoyancy) was replaced primarily because it could no longer hold up the center bridle under the accumulated weight (nature's sentinel). It was slowly sinking.
Also, as PS pointed out in its article, the metal rod through the buoy did not have much life left. Last, I now use only braided nylon line for pendants. My experience with three-strand nylon proved that this type of line does not hold up under the constant twisting caused by tidal and wind shifts. Strands that twisted out of shape would never return to their original state (this was good New England Ropes line).
Overall, I have been very happy with the three-leg mooring system concept. The boat is "anchored" to the bottom on a 7:1 rode with triple redundancy. The boat stays put with absolute minimum swing; even at night or in a fog I know where to look for her. The stretch of the long nylon line minimizes any shock impact; the system has withstood a 60-mph wind. There is minimum chafe on the bottom as the line is elevated off the bottom toward the bridle. The system is very easy for just one man to deploy and took one hour after setup—the heaviest single items were the anchors. The triple redundancy lets me sleep at night and I no longer worry about maintenance until one leg fails because I have two more left. Best of all, the initial payback period was only 5.1 months at local marina rates and my total cost has averaged only $20.59 per month over the life of the system.
Gig Harbor, WA
A mooring that lets a boat swing to conditions is certainly preferable to a dockside arrangement, especially in heavy weather, but marina docking is a fact of life for most sailors without private access to the water, and it has its many conveniences.
This is an interesting system, not often seen for a permanent mooring. It's made of relatively inexpensive parts, doesn't require a muscular mooring-setting boat and crew, and offers redundancy in the event of a failure. Clearly, it requires watchfulness and maintenance—but so does any mooring system. You might consider using stainless steel mousing wire rather than nylon cable ties on the shackle pins, or a Crosby-type bolt shackle with a cotter pin for security.
I looked forward to reading your "Integrated Instrument Systems" article [July 1], as I have been contemplating buying a system for my boat. But I was disappointed to see that you omitted any mention of Tacktick's new Micronet line of instruments. They have the same features as the other brands, but have the added benefit of being solar-powered (with battery backup for nighttime use) and wireless. Thus you can install the wind sensor without running any wires up the mast, and you can move the displays without rewiring. In my opinion this is a major step forward in instrument design. So why no mention of it?
Tacktick instruments were mentioned briefly in the editorial of that issue, "Watching The Flashers," because we have some Tacktick instruments on our test boat—and like them, so far. We didn't cover them in the review because we received no feedback about them from the instrument installers we talked to. The newest Tacktick system, to which you refer, is too new for there to be much of a track record among the pros. There's a concise and well-written overview of the system by Tony Bessinger in the July/August issue of Sailing World, including a sidebar on the 802.11b frequency used to transmit data around the boat.
Those Moorings Pros
Enjoyed Tim Cole's recounting his bareboat charter on a Moorings cat in the waters off Belize [May 15]. My wife and I had our first charter experience this past May on a Moorings boat out of Tortola. His characterizaton of the quality of the Mooring's staff was dead-on. Even though I've been racing and daysailing for most of my 55 years, I felt it prudent to hire on a captain for our charter, someone intimately familiar with the local waters. I wasn't about to gamble with someone else's 750K boat.
From the receptionist who greeted us to the dock hands, everyone was friendly, helpful and eager to please. Our captain, a 26-year-old ex-pat British fellow, was professional and personable. His briefing was casual, but informative: "I don't lay down a bunch of rules. Just use common sense and your past experience. If you're about to break my boat, I'll tell you!"
One of our guests is an avid SCUBA diver. Turns out our captain was a certified diver, and having read the brief CVs we'd submitted ahead of time, brought along his gear and buddy-dived with my friend. Our guest was thrilled.
When you're spending large sums to get to an unfamiliar island and boarding a boat you're unfamiliar with, the professionalism exhibited by people like the Moorings staff goes a long way to making one's experience that much more wonderful. We've already plunked down a deposit to return next year.
...Where Credit Is Due
To Wilcox Crittenden, Middletown, RI:"I was having two problems with Wilcox Crittenden fittings that were installed on my Creekmore 37 sailboat when it was built 40 years ago. The bronze deck fill fitting for diesel fuel was leaking rain and seawater, and so were the fittings for the freshwater tanks. One of the seacocks leaked, but if you took up on the gland nut to stop the leak, you couldn't close or open it—a safety problem. I e-mailed Wilcox Crittenden but was told they no longer made these fittings. However, I was invited to call their toll-free number if I had more questions. Taking them up on the invitation, I asked diplomatically to talk with someone who worked for them in the days when they made these fittings. I was put through to Kirk, who advised me about the size and thickness of the O-rings that should be on the deck fitting caps. He asked for specific dimensions of the seacock and we figured out that it leaked because the flange on the spindle shaft is the wrong size. How that came to be is a complete mystery. Kirk found a flange of the correct size lying around and mailed it to me. No charge.
"Kudos to Wilcox Crittenden and to Kirk! Advice to marine manufacturers: Don't get rid of the 'seasoned' workers who know how the equipment you used to sell goes together."
-Ed Douglass, Sturgeon Bay, WI
To Adler/Barbour, Clinton, CT: "Recently I decided to revamp our refrigerator and freezer for more extensive cruising. This entailed adding insulation and completely changing the mechanicals. I decided on separate compressors and evaporator plates for the refrigerator and freezer. Unfortunately, the design called for some fairly complex custom work for the evaporators. For quality reasons, I wanted to use Adler/Barbour, but since it was the industry leader, I was concerned that they might be too impersonal to take care of my special needs.
"Nothing could be farther from the truth. Scott Tucker at Adler/ Barbour worked with me over several weeks to get exactly what I needed for the refrig and for the freezer. He offered advice, offered an 'off-catalog' item that better fit my boxes, and was generally very helpful—all at a fair price. The second unit was shipped within 24 hours of my order—and this for a custom-made unit!
"Hats off to Adler/Barbour. They may be the industry leader, but they have not forgotten how to help customers."
-Mark Cain, Tampa, FL
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