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A brief guide to 3-strand rope splicing. 

Having a permanently fixed loop (eye splice) on a rope-end removes the need to tie and then untie a knot each time you wish to use it. Splicing is a very strong method of fixing a loop eye; as the rope is pulled tighter so the spliced strands become more and more squeezed and locked in place. Splicing removes the worry of a knot becoming undone and a spliced eye is less bulky. You can buy 3-strand rope (and 8-strand) with an eye already spliced in by the supplier or you can make your own.

Now start to pull all 3 strands through the rope evenly. Note how they are all aligned along the rope (the red is hidden at the back).

Its crucial to get the first weave correct so that all following weaves lay correctly.

Pull the three strands tight.

Now continue to weave by threading each strand through one coil in turn. Do this by passing the strand over a coil and then under the following coil.

Once each strand has been threaded once, pull the weave tight by tugging on each strand in turn. Keep them as tight as possible.

This picture shows the blue strand starting its second weave with the red strand already threaded twice.

Continue weaving. Remember to keep the strands tight.

This picture shows 3 weaves completed for each strand with the red strand starting its fourth by passing over and then under a rope coil.

Weaving is now complete. You need a minimum of 5 weaves for each strand, I've completed 6.

Trim each strand by leaving a stub of 25mm or so. I wrap mine with tape and then heat seal the end with a cigarette lighter to keep it neat and to prevent it from separating.

The finished article.

Please note, the guidance contained in this web page has obvious limitations. It is recommended that you obtain proper instruction from a relevant training provider before using spliced ropes for serious applications.

1. Pass the line once around the post.
2. Pass the line around again, this time going over the original line.
3. Tuck the line under the crossing.
4. Tighten it.

1. Pass the line through a block, or a cleat.
2. Make an overhand loop with the free end.
3. Twist the line around the standing part, making a second loop.
4. Pass the free end down through the original loop.
5. Tighten it.

A Stormy Night on the Hook

By Gregory Walsh

A vessel far from home can’t avoid stormy nights at anchor. They are part of the cruising life - something to be endured and, one hopes, survived without mishap. Endurance is psychological, but survival, in this case, is a very practical matter. Getting through a howling night at anchor is a matter of physics, luck, and attention to the details of seamanship. After that it may be a matter of catching up on sleep the following day.

Factors involved include the nature of a boat’s motion, the power of the wind, the nature of anchor rodes and anchors, bottom characteristics, and the duration and direction of high wind forces.

Who hasn’t spent a tense night at anchor, keeping an anxious lookout in rising wind conditions and building waves, not knowing from one minute to the next when, or if, a boat might suddenly begin dragging and what the results of such a catastrophe could be? Who hasn’t sworn at such times that the boating life is just not worth the stress that can fall upon captain and crew? Nor can it be worth the risks involved in possibly losing such a huge financial and personal investment, not to mention the risks of injury or fatality that could result from a dangerous grounding. But then, as with so many aspects of life, there always comes the next morning’s hearty sunshine to chase away those thoughts of discouragement.

The anchor held, but was it luck or was it because the boat was fitted out with appropriate ground tackle and the knowledge of how to use it? In most cases, all three are involved.

Power of the wind

As wind increases, the force or pressure generated by the wind goes up by a factor of four. It is not a linear progression. For example, the dynamic pressure against a boat in a wind speed of 60 knots is actually four times that acting against the same boat in 30 knots of wind.

Force of wind, F, varies with the square of wind velocity, V^2, and the surface area of a boat, A, according to the following formula, in which the velocity of wind is calculated in miles (30 knots x 1.15 = 34.5 mph):

F = 0.004 x V^2 x A

Thus, a 30-knot breeze can generate 4.8 pounds of force on every square foot of boat exposed to the wind. If you consider that a large sail or powerboat might have 300 to 400 square feet of surface area, that would be approximately 1,500 pounds of force exerted on that boat (assuming it is bow into the wind), trying to pull it backwards, to break that anchor out of the bottom. That’s like having a small boat with a 150-hp outboard engine come along and lasso one of your stern cleats and pull backwards with full throttle.

Yaw and Swing

  When a boat swings its bow away from dead into the wind, its exposed surface area increases dramatically, as does wind force. For example, an Eastbay-40 power boat, which might be considered a typical 40-foot power cruiser, presents approximately 160 s.f. of boat, rigging, railings, Bimini covers, and side curtains to the wind when it is at zero angle to the wind, according to its designers at C. Raymond Hunt Associates, Boston. But when the same vessel swings its bow just 30° off the wind, the exposed surface area suddenly increases to 447 square feet. In that situation, wind force in 30 knots of wind would increase from 770 pounds to 2,146 pounds.

It is the same with any sailboat: As soon as the boat yaws, wind forces begin to increase alarmingly. Forces can, indeed, get out of control when a boat yaws to angles of 45° or 60° or more. When a boat begins to drag or when the weakest link of an anchor rode breaks, it usually happens when a boat has veered off to one side or the other. With this in mind, it should be clear that one of the keys to staying put at anchor is to eliminate or reduce yawing. Another important factor is to make sure that a vessel is equipped with anchor, chain, shackles, swivels, and nylon rode, all with sufficient strength to resist such forces.

There are several basic motions of a vessel at anchor: swinging, which is a circular movement around the pivot point represented by an anchor; surging, which is a forward and astern motion relating to the anchor’s position; pitching, which is a vertical motion of a vessel’s bow as it rides to its anchor in various wave conditions; and yawing, which occurs as a vessel’s bow is blown away from the wind. Of these, it is primarily yawing and pitching that can cause a vessel to drag anchor - yawing because of the forces involved, as we have already seen, and pitching because of its tendency to jerk on an anchor rode that has lost its curve or catenary.

Two important design factors are also involved in a typical anchoring situation: Center of Effort and Center of Lateral Resistance.

  Center of Effort is the point through which all wind forces tend to act on a boat. It is different for all vessels and it varies with conditions of sail, rigging, deck gear, cargo, and deck structures. It is, in effect, the total average midpoint of everything taken together on the boat above the waterline. An invisible finger pushing on the CE would simply make a boat heel directly over to one side. It is an important factor to consider when a boat is anchored in rising wind conditions.

  Center of Lateral Resistance is the geometric center of the bottom configuration. If one were to dive underwater and push on the CLR, the boat would theoretically move directly sideways. CLR can change as a vessel heels, but it generally doesn’t move much.

In most situations the CE and CLR need to be reasonably close for a boat to be balanced and handle properly. Strategy for boat anchoring is also a function of these factors. The CE usually is forward of the CLR, even for an anchored boat. This is because of the traditional shape of a hull without sails - there is more mass up forward. Different styles of boats have more or less mass forward of the beam.

A vessel’s tendency to yaw or swing is enhanced as the CE moves forward of the CLR. The more surface area there is forward of the CLR, or forward of amidships, the more yawing tendency will develop as winds and waves increase.

If the CE can be kept aft - or moved aft - a boat’s tendency to ride properly at anchor will be much improved. That is one of the great advantages of a yawl or ketch rig, or of a vessel equipped with a small riding sail flown from the backstay. These small, flat sails tend to move the CE aft and keep the boat weather-cocked up into the wind. (The sail must be completely flat, however, so as not to drive the vessel ahead.) Considering the awesome power of a gale of wind, any such riding sail or mizzen sail must be tough and very small, perhaps just a few square feet, so as not to be overpowered. Just as often, however, even the smallest riding sail must eventually be doused as the wind reaches the upper ranges of intensity. What may save a boat at that point are efforts the crew has already made to move the CE aft by reducing windage as much as possible forward of amidships (stripping sails, booms, excess rigging and equipment, etc.).

Yaw, of course, is difficult to avoid, since the force of wind and waves almost always strike the boat at some point forward of the CLR

The motions of yaw and swing seem almost inconsequential when anchored in light conditions. As wind increases, however, the tendency to yaw and swing can combine with catastrophic results. As soon as a boat’s bow blows off the wind (the boat turning on its vertical axis) it will begin to swing off to one side because of the force of wind on its side. As more of the boat’s side is exposed the tendency both to yaw and swing will increase. Before long, in the worst situations, a boat may be swinging back and forth like a pendulum at the end of its anchor rode, each time yawing so as to present a different side to the wind. The acceleration of swing in each direction can dramatically increase the forces involved, especially at the apex of each swing. All the work of stopping the swing, reversing the bow, and holding up to total wind force falls directly on the anchor and its gear. Total loading on the anchor gear consists of pure wind force per square foot, plus additional forces for acceleration or momentum of swing, surge, current, and wave action.

An important technique for eliminating or reducing yaw or swing is to drop a heavy weight or a spare anchor directly off the bow of an anchored vessel. This dragging device should be lowered just enough so that it stays close to the bow of the boat, perhaps 1.5 times the water depth. If it is heavy enough, or if it can dig into the bottom somewhat, it could make it difficult for the bow to move around. Care must be taken, however, not to let out too much scope nor to allow it to foul the primary anchor rode. Lacking an appropriate spare anchor, two or three cement cinder blocks tied together might make a suitable heavy weight for this purpose.

All-important Catenary

This is particularly true in the case of all-chain anchor rodes, which, without catenary, are no different than a long steel bar connecting the boat and its anchor. Since chain has no stretch, as soon as the bow pitches up because of a wave, it will directly jerk on the anchor if there is no catenary.

It is for this reason that nylon rode is so often recommended in all yachting applications. Nylon has legendary capacity to stretch, and it is stretch, in extreme conditions, that might keep that anchor from being jerked out of the bottom. Introduction of nylon may not increase catenary directly, since it is lighter than chain, but its ability to stretch is equally as important as the heavy weight of chain, which tends to build its own catenary. The ideal anchor rode for heavy wind conditions should be 50 percent chain and nylon. This is because nylon rope is known to be able to stretch as much as 40% of its length without breaking. At recommended working load, it may stretch as much as 25% of its length without damage.

An all-nylon rode, on the other hand, is too light and has no natural catenary by virtue of its own weight. Many voyagers also fear that an all-nylon rode will be prone to chafe as its lower half makes contact with the bottom. If a 50/50 mix of chain and nylon is not practical, then a voyager might endeavor to have an amount of chain equal at least to the weight of his anchor. (Specifications on weight and strength of chain are readily available from any supplier).

Ideally, a vessel should be able to set 200 to 300 feet of anchor rode to obtain sufficient scope in heavy-weather conditions. To attain 7:1 scope in 30 feet of water, for instance, it would be necessary to veer out at least 210 feet of rode. In light weather conditions, smaller amounts of scope are required, especially with mostly chain anchors. (In light to moderate weather, all-chain rode can safely use as little as 3:1 scope.)

Many voyaging vessels adopt the practice of using an all-chain rode and then attaching a length of nylon to the rode by use of a chain hook spliced into the end of the nylon. The chain hook can be attached to the chain rode wherever appropriate. By this means a vessel can pay out 100 feet or more of heavy nylon while also paying out an equal amount of slack or "lazy" chain. To benefit from such an arrangement, however, it is necessary to pay out a good length of nylon, not the nominal six feet or so that is often seen in a cruise around an anchorage. One hundred feet of nylon allows far more stretch than six feet of nylon.

There are problems with this technique, however. First, the hook typically is a rusty, messy thing, and it can and will fall out in an unpredictable way. More significant, a chain hook, by its nature, makes connection across a link of chain, and thus the full load of the rode will be applied across that link in an awkward way for which it was not designed. It’s an eccentric load, applied sideways to a single link. It might be better to shackle the thimble of a long length of nylon into the chain rode, but that requires large enough chain links to take a shackle pin—not very likely considering the small chain used by most yachts.

The solution in that case might be the use of an enlarged link inserted into the chain at a preselected length—say, after the first 75 or 100 feet of chain. Design and installation of an enlarged link requires a fair amount of preplanning, and this “storm link” would need to be inserted within the chain by use of detachable links, which are readily available at marine chandleries.

Yet another solution might be use of a flat plate of stainless steel with a slot cut into the one side large enough to accept a length of chain in a non-eccentric way. Such a plate will more likely take a fair and clean bite on the chain and is less likely to fall out. A plate would also require one or two holes on the opposite end for attachment by shackle to a long length of nylon. Even better, use of the plate technique would not require introduction of an enlarged storm link into the chain rode. Perhaps more practical would be use of a heavy steel (ideally stainless) “devil’s claw” type of chain grabber, which could also grab onto a chain link in a non-eccentric way and could easily attach to a nylon rode by a single shackle.

Use of a detachable length of nylon might only be required in a particularly nasty anchoring situation—that once- or twice-a-year storm. In most other situations an all-chain rode would have sufficient strength, durability, and catenary to carry a boat through the night, providing a sufficient amount of scope was deployed.

Use of a Sentinel

Location of the sentinel on the rode is important. To be most effective the weight should be set somewhere in the first half of the rode (closest to the anchor). The idea is to keep the initial section of rode weighted down as close to the bottom as possible.

How much weight is involved? A rule of thumb is that the weight should be a bit less than one pound for every foot of boat length. For a 40-foot boat, that would mean a sentinel of 30 to 40 pounds.

Use of a sentinel weight should be a standard tactic for the yacht skipper faced with deteriorating weather when at anchor. Others, as already discussed, include veering out more rode, increasing the amount of nylon in a rode, stripping the bow of a boat to move the center of effort aft, use of a small riding sail aft, and reducing windage in general.

Use of a Buoy

Use of Engine

Therefore, the priorities should be: 1) set a proper anchor with adequate scope; 2) stop yawing and swinging; 3) ensure there is catenary; and 4) maybe then use engine power, but not if it causes or exaggerates yawing or swinging.

Many a skipper has spent a night motoring into the wind while anchored. In many cases it is an effective technique. Motoring should obviously be initiated before a vessel begins to drag anchor. Motoring, if nothing else, can help to keep enough catenary in the rode to prevent the anchor from being pulled out.

Motoring can be extremely frustrating, however, especially for the person at the helm who may not have a good sense of the effect of motoring, not being able to observe the rode and not necessarily always aware of the extent of yawing. In a heavy rain and wind situation the helmsman may really be blinded, especially with cabin lights and sometimes spreader lights switched on in the night. It may help to have a person on the bow observing the effect of motoring and coordinating those observations with the man on the throttle and helm. Once motoring is initiated, however, crewmembers should be prepared to relieve each other regularly at the helm and lookout. A long, sleepless night is assured.

Use of a storm anchor

 A 150-pound Luke anchor (Paul E. Luke Co., East Boothbay, Maine) might just save the day for a 40-foot yacht preparing to anchor out in approaching bad weather in some faraway port. It can be dragged out in pieces, assembled on deck, and lowered over the side by a couple of crewmembers, even using a halyard if necessary. Such an anchor might also come in handy if a boat is to be left untended but anchored out for some period of time in a strange port.

Along with the storm anchor, a skipper might pull out a 20- or 30-foot length of heavy chain—say, three quarters of an inch—to attach to the storm anchor to beef up the weight of the rode and catenary. This is no extra trouble since the end of the rode is being reattached anyway, and the heavy chain can be stored away almost anywhere on the boat when not in use. It should be evident that a boat should always have a good supply of heavy galvanized shackles of all sizes for just this sort of work. And no matter what the situation, all shackle pins should be moused tight with wire before anything goes over the side. Chafe gear is also essential—leather, fire hose, or plastic tubing—especially where sections of nylon might be vulnerable.Setting the anchor

Last, it always helps to know that an anchor has been set properly before a storm. In theory, one might select an ideal spot within the anchorage and pilot one’s way precisely to that spot. Other boats, however, often tend to get there first and nab the best spots for themselves. When an anchor is first deployed, a yacht’s bow will likely fall off the wind, but once the anchor “catches” it will haul the boat’s bow right back up into the wind, hopefully to remain there. Once the anchor is set, one must remember to select objects for visual bearings during anchor watches, remembering that only a few of those will be visible at night.

If bad weather is expected or if a visit of more than one night is planned, then it might be wise to immediately deploy a full storm amount of scope—or close to it—so as to stake out one’s territory within the anchorage. If another vessel were to anchor close astern, then there may be no more room available to veer out a proper amount of scope when the wind begins to get really serious in the middle of the night. Boats anchoring too close should be politely warned away if a bad night on the hook is anticipated.

The use of an engine to set an anchor should be done cautiously. Sometimes, when this happens, the boat is backed down when the boat’s bow is still off the wind and before the anchor has caught. It may be better to back down gently after the anchor has caught and after the bow has swung up into the wind. Use of a backing engine too early may jerk the anchor chain or rode, actually discouraging it from setting properly. But once the skipper thinks it is set, he can test it by putting the engine in reverse—the boat should stay put, after most of the catenary has eased out of the rode. If it is not holding, the anchor chain may tend to come taut and then go slack, and to keep repeating that with a “jumping” motion while the boat is backing under power. This jumping can be easily felt with one hand on the chain or rode.

If the anchor is not holding and the engine is not backing, the vessel’s bow will simply never swing up into the wind. This is typically the surest sign of a dragging anchor—a vessel’s bow will fall off the wind and stay off the wind. In that situation, veering out more chain may solve the problem, but there is a good chance the vessel will have to haul back and reset the anchor.

If the anchor is holding, the boat may periodically slew off to one side as it yaws to a fresh breeze, but it will always come back to the wind, the rode will come tight, and bearings or ranges on shore won’t change.

It should be noted that in nasty weather a vessel can, indeed, drag its anchor straight back in the direction of the wind, just a little bit at a time, without having its bow blown off. In such cases the anchor would keep resetting itself. The only way to check for this is by observation of bearings abeam or close to abeam, or combinations of bearings and the use of radar or GPS to determine if the vessel’s position is changing. With an anchor dragging in this fashion, veering out another few fathoms of chain may very well correct the problem, assuming the anchor and its gear are sufficiently heavy.

All of this assumes that a vessel is setting up to anchor with a single anchor and the best possible equipment and rode. The use of two or more anchors can be considerably more complicated and might be best avoided, providing a vessel has a sufficiently large primary anchor. This is especially true in areas north of the tropics, including virtually all of the U.S., because the passage of cyclonic storms, as well as hurricanes, almost always involves dramatic wind shifts as a storm passes by. Wind shifts can make things awkward for a vessel that has two or more anchors deployed. In addition, the use of two anchors ideally requires two sets of nearly identical gear, something that might be difficult for most yachts to maintain.

Given a single large anchor with good related gear, a yacht should be able to ride out just about any night of bad weather. The trick is to have equipment ready and to plan all appropriate strategies, anticipating gradually increasing winds and increasing chop or waves in the harbor. Explain every planned step to crew and try to envision the difficulties of accomplishing the task in howling wind and driving rain, all while working on a bouncing deck with the anchor gear under considerable stress.

One final item: there’s usually no harm in exercising all possible tactics in advance if it’s a sure thing that the weather is going to get bad. There’s nothing to be gained by waiting until the situation is desperate!

© 1997 Navigator Publishing Corp.

Reprinted from Ocean Navigator magazine

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