to the lifelines cause a constant force, and in certain conditions, a significant force on stanchions and deck. The result is gel coat cracks, deck leaks, and fatiguing of the metal base, welds, and fasteners. A cruising friend in Mexico with a Valiant 40, was lamenting at the cost to fix a sheared off stanchion base. He explained that while docking, an overzealous dockhand attempted to slow the boat by pushing at the top of the stanchion. Though expensive, the owner agreed that it was good to find out the weakness at the dock instead of offshore. Force equals mass times acceleration, so the weight of a person (mass) falling (acceleration) against the top of a stanchion is already a huge force. If the stanchion is two-feet high, the force at the base is doubled and quickly gets to be thousands of pounds. As a rule, it’s a good idea to carefully inspect stanchions and pulpits at least annually. While on our recent 3,000 mile

passage from Mexico to Hiva Oa in French Polynesia, our most exciting gear failure was due to shock loads further magnified by a simple machine.

The failure was at the mainsheet to boom attachment point; a 3/8” stainless steel U-shaped eye. We were broad- reaching in little air, with very lumpy swells from two directions. To reduce slatting, the mainsail was reefed and held fast with the mainsheet, preventer, and vang tightened. Still, the slatting main caused shock loads that among other things, tried to roll the boom much like a flat hand can roll a pencil across a desk. As the U-shaped eye extends beyond the bottom surface of the boom, the wheel and axle machine magnifies that shock force. Fortunately, when the U-shaped piece sheared off, the light air, daylight conditions kept it from being difficult. Our prior mistrust of the connection

led me to have a webbing strop already in place around the boom making the repair simple. A webbing strop is a single continuous piece of webbing forming a circle with several layers sewn together. Strops are a strong, durable, and inexpensive alternative to a metal eye or shackle. And, in the case of the mainsheet to boom attachment, the strop allows the upper

mainsheet block to naturally rotate to a position, eliminating the wheel and axle machine. From fire extinguisher handles

to winch handles, so many examples of simple machines exist that we take them for granted. Worse is being unaware of common features that can cause a small force to grow significant, like our friend on the Valiant. Take some time now and again to identify simple machines that can cause not so simple problems. You may be frustrated by not being fully comfortable with sailor speak so that the call of, “The damn lazy guy is wrapped around the sheet,” sent you below to wake up your husband. The crews’ levity at your expense may be short lived when, at the dock, you remove all the fenders that they attached to the lifelines and reattach them to the stanchion bases, explaining about negative affects due to the misapplication of leverage.

Our radio stopped transmitting about

halfway across the Pacific. We’re doing fine here in the Marquesas but hamstrung for email transmission. This is coming to you from our friends on the sailboat “IO”.

Master ocean voyaging, with instruction, in the South Pacific aboard Mahina Tiare III, a Hallberg-Rassy 46.

With a combined experience of 526,000

miles and 67 years, John and Amanda Neal’s curriculum offers you a unique hands-on learning experience.

www.mahina.com • 360.378.6131

48° NORTH, JUNE 2010 PAGE 41 Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98