Most of the time I have made do by careening, which is to let the boat lay over on its side as the tide drops and, if necessary, heeling her over even further by hauling on a halyard connected to a secure point on shore. But this means that only one side of the boat is accessible at a time. Safe careening requires a firm, smooth shoreline, such as a sloping sandy beach. Even so, the hull is vulnerable to damage from pounding against the bottom if an unexpected swell or wake from a passing boat should arrive. It is also extremely uncomfortable to live on the boat while it's laid over at a crazy angle. And getting up in the middle of the night at high tide to move the boat out or to turn it onto the other side is no fun either.
While in Madagascar, I even experimented by standing Atom bow-on to the beach with an anchor set out to each side connected to halyards at the top of the mast. This system sounded fine in theory, and may even have worked if I had not upset the balance by stepping off the side of the boat, causing one of the anchors to move slightly from the increased load. Moving in slow motion, Atom rolled gracefully and unstoppably over on her side. Fortunately, the only real damage done was to the skipper's pride, as witnessed by a group of curious local fishermen who gathered around.
While on that six-month cruise around Madagascar a few years ago, I began to seriously consider designing some type of dry-out legs. Besides keeping the boat upright for maintenance work, I wanted a method where I could enter shallow coves and tidal rivers at high tide, drop my anchor, set up the legs and let Atom look after herself as the waters receded. Some European sailors who keep their boats on moorings where huge tides turn the bays and estuaries into narrow channels and vast mud flats use what they call dry-out legs. However, the only types of legs I had seen in use were bulky and difficult to stow. Most of them lacked any height adjustment and I didn't care for the way they were attached to the hull, requiring special fittings and reinforcements.
Eventually I came up with a design using two sets of adjoining stainless steel pipes connected together with a standard pipe coupler and attached to the existing shroud chainplates. Their height and angle of inclination are fully adjustable and the plywood feet that I designed for them pivot in order to be used on an uneven seabed. Because they attach to the existing chainplates, they do not require any modifications to the boat at all. In addition, the chainplates are better designed to take heavy loads than most fittings that you might add on later. When not in use, the legs disassemble and stow easily in the bottom of a cockpit locker. An added benefit of these legs being fully adjustable and attaching to the chainplates is that I can loan them out to friends with boats of similar size and draft.
The feet are made up from one-and-a-half-inch thick, epoxy-laminated and sealed, pieces of scrap marine plywood. I was initially unsure as to what size would be best for the feet, wondering if I might even need a second set of wider feet for muddy bottoms. To calculate the correct foot size I began with the rough calculation that my full-keeled, 10,000-pound boat (fully loaded) would put, say, a maximum load of about 2,000 pounds on each leg. So I conservatively guessed that I'd need to keep the foot pressure load under 20 pounds per square inch, and I found that this could easily be handled by a surface area of 10 inches by 12 inches, or 120 square inches.
After testing, I was pleased to find that the feet do not sink in excessively, even in the muddy river bottoms of Brazil where I used them recently. In practice there is normally not much load on the legs, but they still should be massively overbuilt to withstand the possible shock loads from waves that arrive just as you are taking the ground or starting to refloat. On one of the legs I later added two small steps to facilitate getting on and off the boat at low tide.
|"To lessen the chance of pounding on the bottom it's prudent to choose a spot that is well protected from waves and wakes."|
I prefer to set up the legs while still afloat to avoid a panic trying to get them set up before the falling tide heels the boat. I begin by loosening the aft lower shroud turnbuckles and removing the pins. With the legs assembled on deck, I then lower each one over the side, and attach it to the chainplate. A rubber block slid over each leg protects the hull from scratches. The legs are clamped at a pre-marked position so that the feet are level with the bottom of the keel. Lines attached to the forward end of each foot are tied to the bow cleat, and then the aft lines are pulled tight and tied to the stern cleats. (I occasionally use the cockpit winches if necessary for final tightening.) These four lines tend to pull the feet inward at the bottom. To oppose this force, and to ensure that the legs will incline slightly outward, I pull a line tightly across the deck between the top of each leg.
The legs have proved a valuable addition to Atom's cruising gear, opening up shallow waters that were previously out of bounds, and making her a more versatile and self-sufficient boat. Even in areas where the tidal range is less than your boat's draft, setting up the legs can be useful when replacing a thru-hull fitting or the prop, or just cleaning the bottom. And, when you want to anchor in that enticing deserted cove that is just a little too shallow for your boat to remain afloat at low tide, the legs will make that possible.
|Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)|