A PRACTICAL GUIDE TO THE MOORING AND ANCHORING OF SMALL BOATS
A PRACTICAL GUIDE TO THE MOORINGAND ANCHORING OF SMALL BOATSPage 1
INTRODUCTIONIn recent years it has become increasingly obvious that the basic principles ofanchoring and mooring are often imperfectly understood. Inevitably this has led toequipment failures, either through poor system design or through the selection ofunsuitable components with consequent damage, injury and even death.It is all too common to find extremely expensive craft, the pride and joy of theirowners, put at risk through ignorance of a few simple rules. Even worse, wholefamilies can be put in danger through misguided economies by owners orcontractors. Surely a classic case of ‘spoiling the ship for a ha’porth of tar!’ Yet all itneeds is a little time spent understanding the principles and a little care inselecting equipment.This booklet has been produced in an attempt to guide you through the variousstages of design, selection, installation and maintenance. It contains practicalinformation for the owner and contractor alike. We hope that you will find it usefuland that it will help you to sleep sounder (and safer!) when the wind is whistling inthe rigging. 1987Bradney Chain & Engineering Co. Ltd.,Quarry Road, Dudley, West Midlands, DY2 0EBTel.: 44 (0) 1384 636233Fax.: 44 (0) 1384 634289Email: sales@bradneychain.co.ukWebsite: www.bradneychain.com
CONTENTSPage1. A HISTORY OF MOORING & ANCHORINGthe development of the marine anchor – the developmentof chain12. MODERN ANCHORStraditional anchors – stockless anchor – fisherman anchor –grapnels – lightweight high-efficiency types – ploughanchor – cruising anchor – mooring anchors – mushroomanchor – single-arm mooring anchor43. CHAINS AND OTHER COMPONENTSstrengths – grade 30 – grade 40 – grade 60 – grade 80 –stud link anchor chain – short link chain – long link chain –twisted link chain – calibrated chain – other components –shackles – swivels – rings, links and other fittings64. DESIGN CONSIDERATIONSforces exerted on moorings – wind drag – current drag –wave action load – snatch or shock loads – how anchorswork – holding power – the effect of increased loads95. PERMANENT MOORINGSsingle-anchor moorings – clumps – multiple-anchormoorings – trot moorings – pontoons, fish cages andsimilar structures – laying a mooring – maintenance –permissible wear126. ANCHORINGusing two anchors – tripping lines – safety167. CHAIN versus ROPEstrength – chafe – scope – connections – conclusions218. SELECTING CHAINS FOR MARINE APPLICATIONSproduct quality – corrosion and abrasion – materials forchainmaking – wrought iron – carbon steels – alloy steels –stainless steels – conclusions22APPENDIXsuggested sizes – anchoring – permanent moorings –approximate chain weights24NOTES26
1. A HISTORY OF MOORING & ANCHORINGTHE DEVELOPMENT OF THE MARINE ANCHORSt. Clement, the fourth Pope (88-97 A.D.), is the patron saint of anchorsmiths. Storyhas it that he was tied to an anchor and thrown into the sea – a not uncommonmethod of execution in those days.Egyptian tomb furnishings provide the earliest anchoring records. Ship modelsdating back to 2200 B.C. have been found equipped with conical stakes andpapyrus ropes for mooring the vessels to the shore. Later tombs, around 1600 B.C.,have yielded similar models boasting grooved or perforated anchor stones. KingTutankhamen’s tomb, 1400 B.C., disclosed anchor stones shaped like theletter ‘T’.Over the next thousand years this ‘T’ shaped stone developed into arudimentary stockless anchor or two-armed hook. The design graduallyimproved and it was made in various materials. Sardinian anchors ofaround 650 B.C. are believed to have been made of iron. Bronze anchorswere cast in the island of Malta around 500 B.C. (Fig. 1). Greek writers ofabout the same period mention stone anchors fitted with iron hooks.Early wooden anchors known as ‘killicks’ were little more than crookedsticks or wooden frameworks weighed down with stones. Similaranchoring methods are still used in a few remote regions. The interestingpoint, however, is that some of these crude anchors had a rudimentarystock, which brings us to the next major development.Around 400 B.C., probably in Greece, a two-armed hook was fittedwith a stock (Fig. 2). The Greeks were apparently responsible forsignificant developments in anchor design as Greek coins of around280 B.C. indicate. These show iron anchors with stocks andrudimentary palms, which are recognizably similar to the Admiralty orfisherman patterns in use today.As would be expected, anchor development also shows the influence ofRome. Iron anchors of King Herod’s time, about 35 B.C., have clearlydefined palms and peculiar enlargements on the shanks. These arethought to be a throwback to times when cylindrical perforated stoneswere tied to anchor shanks. When Lake Nemi, near Rome, was drained in1929, two 1800-year old Roman anchors were discovered. One was aniron-tipped oaken anchor with a heavy leaden stock belonging to theEmperor Caligula’s ship of about 40 A.D. (Fig. 3). The second was awood-sheathed iron anchor with a removable stock for easy stowing. Thisinvention was lost to the world until it was ‘re-invented’ some 1700 yearslater!In fact, anchor design changed little over those 1700 years. The samevariety of materials – stone, wood, bronze and iron were all used,proportions varied and palms became somewhat more pronounced. By1700 the prevalent anchor was the ‘kedge’ type with a long shank, straightarms at 50 degrees, and of iron construction with a fixed wooden stockthe length of the shank or longer (Fig. 4).The 19th century was one of innovation. At the beginning of the centuryiron stocks began to be seen, anchor shanks were tending to becomeshorter and arms more curved. In 1807 the Royal Navy permitted the use of ironstocks for smaller sizes of anchors. Over a hundred ‘improved’ anchors werepatented in rapid succession, practically all of which are today regarded as freaks(Fig. 5). Anchors were introduced with cant palms, tripping palms, stockless shanksand tumbling flukes, but all struggled to win general acceptance. By 1840 thePage 1
Hawkins patent tumbling fluke stockless had developed into a formsimilar to most of today’s stockless anchors. Major purchasers, however,were conservative of change and it was 1846 before the Royal Navy fullyaccepted the iron stock and sanctioned the use of the anchor now knownas the Admiralty pattern (Fig. 6). Although slowly gaining favourstockless anchors were still in the minority. It was not until the 1880’s thatthe great benefit of a stockless anchor was generally realised. All otheranchors were very awkward to stow on board, having to be catted intothe ship’s cathead just aft of her bows. The stockless anchor will stow in aship’s hawse pipe and for this reason it remains today practically theonly type of anchor used on ships of any size.Two other significant developments took place during the nineteenthcentury. In the 1850’s the mushroom type of anchor appeared. This was,and remains, especially suitable for certain types of permanent mooringsand has been widely used for lightships and naval moorings. Late in thecentury there was a revival of the ancient practice of putting the stockthrough or near the head of the anchor. ‘Head stocked’ anchors have theadvantage of high holding power, especially in soft bottoms. The cruising(Danforth) anchor is an example of this type still very popular today.Modern small boat anchors have all been developed to dig into theseabed when subjected to a horizontal pull. Designs are available whichoffer enormous holding power for their weight – but they must still havesufficient weight. Below about 7.5kg the scale-effect starts to rob them oftheir effectiveness. Some of the more popular types of modern anchor arediscussed in Chapter 2.THE DEVELOPMENT OF CHAINThere is ample evidence that prior to the eighteenth century metal chain was usedin building, as jewellery, and for prison fetters. Surprisingly, there is only a littleevidence of chain being used to anchor or moor vessels.Somewhat less surprisingly, the first record of anchor chain comes from China,whose civilisation was far in advance of the rest of the world. Around 2200 B.C. thefabled Emperor Yu is reported to have used “iron chains, two fore and aft, whichwere thrown overboard to steady and stop the vessel”. Hebrew legend tells us thatHiram of Tyre supplied chains for King Solomon’s ships (950 B.C.). These may wellhave been brass, as the Bible tells us (I Kings vii) that “Hiram was cunning to workall works in brass”. Aristophanes (400 B.C.) informs us that the cables of theAthenian navy were sometimes made of iron. In 322 B.C. Alexander the Greatequipped vessels with iron chain so that the enemy could not swim outand cut his vessels adrift. This was obviously an accepted benefit inthose days, as Caesar (56 B.C.) found the Veneti tribes using iron chainfor the same reason.There is little or no mention of anchor chains from Caesar’s time until the13th Century. From 1200 A.D. to 1600 A.D. there are occasionalreferences, but it is clear that anchor chains were seldom used. In 1634Philip White patented in England a method of making iron chains forships and chain began to be used as a viable alternative to rope.Although George Washington implemented his idea of a barrier chainacross the Hudson River to impede the invading British fleet, most chaindevelopments were taking place in England. In 1783 George Matthewsmade cast malleable chain for ships, an innovation well ahead of its time.It was not until World War I that cast chain was fully developed. In 1808Robert Flinn of North Shields became the first man to produceconsistently good quality anchor chains and these won wide recognitionand were an outstanding success. At the same time Samuel Brown tookout patents for twisted link chain (Fig. 7), joining shackles and swivels.The change from hemp to chain was gathering momentum.Page 2
Studs to stiffen the links and to prevent the chain from tangling appearedin 1812 (Fig. 8). In 1816 the Royal Navy standardised on iron chaininstead of hemp for all new warships and in 1830 decided to equip allnew and existing vessels with iron chains. Testing machines had beendeveloped to prove the quality of the chain and by 1836 the use of ironchains was general and their superiority accepted. Underwriters ceasedto charge a higher premium for merchant vessels using iron chain.In 1846 Lloyd’s Register of Shipping changed their rules to demand thatall chains for classified vessels be proof tested and marked accordingly.In 1835 they had demanded that test certificates should be produced forchains and in 1858 issued rules as to the length and size of chain cable.These moves eventually resulted in the Anchors and Chain Cables Act of1899, which remains the basis of present-day testing procedure.As with anchors, experiments continued into various ways of making chains. In1902 an English manufacturer produced solid weldless chain by taking a bar ofcruciform section and rolling it between specially shaped horizontal and verticalrollers. These rollers produced the general shape of a chain which was thentrimmed and pressed to size. Also in 1902 a patent was taken out for a spirallywelded chain. This involved coiling thin flat bars and pressing the coil at weldingheat to form a square-sectioned ring. Each ring was subsequently formed andtrimmed to the shape of a link.However, at the start of this century, virtually all chain was wrought iron made bychainsmiths on open hearths, with steam hammers to assist on the larger sizes.During World War I there was a serious shortage of chain mainly due to aninsufficient supply of suitable iron. This led to attempts to produce steel chain byfirewelding, which were, in the main unsuccessful. Cast steel chain proved to be aviable alternative, however, and had the added advantage of being of highertensile strength than iron. These factors acted as a major incentive to find adifferent method and led to the successful production of electrically welded steelchain.Modern chainmaking has made tremendous advances in recent years, both inquality of steels and in manufacturing methods. Sophisticated high-speedmachines incorporate the latest in mechanics, fluidics, electronics and microchiptechnologies. Chains themselves come in various grades of steel for differentapplications, some being many times the strength of wrought iron.Page 3
2. MODERN ANCHORSAnchors currently in popular use fall into three broad categories – traditional,lightweight and mooring anchors – while within each category there are numerousdesigns. Each category of anchor is based on a slightly different design conceptand is in consequence more suitable for certain applications than others.TRADITIONAL ANCHORSHistorically, these anchors reflect the experience of mariners for the past 2500years, in that they are a compromise between pure dead weight for hard bottomsand the ability to bite and hold in soft bottoms. The following designs remainpopular today, for very sound reasons.Stockless Anchor (Fig. 9)The stockless anchor retains its popularity for the very simple reason thatit will stow in a hawse pipe. However, most types rely almost entirelyupon weight, and that fact makes them unsuitable in small sizes forpleasure boats. For larger vessels they are ruggedly built, handle easily,and without a stock readily disengage from sea bottoms and submergedwreckage. In small sizes they will hold as a rough approximation 2 to 3times their own weight, and about 5 times in ships’ sizes.Fisherman Anchor (Fig. 10)The fisherman anchor has changed very little over the years. It will hold 3to 8 times its own weight, far less than the modern lightweight patterns,but in spite of this has its uses. It will sit well and remains a favourite onrocky shores or in kelp where other anchors often fail to get a grip andconstantly develops its maximum holding power with less chain laid outthan is required for the lightweights. Its disadvantages are that its palmslack sufficient area to hold well in mud or sand, and if the vessel isallowed to swing round, the chain may become wrapped round the otherfluke – the one sticking up out of the bottom. The result of such fouling isto turn the anchor chain into a trip line.Grapnels (Fig. 11)Much that has been said about the fisherman anchor is equally true ofgrapnels. The folding type, particularly in smaller sizes, remains popularfor very small craft where its ability to stow neatly, easily and in a verysmall space is a significant advantage.LIGHTWEIGHT HIGH-EFFICIENCY TYPESThis century has seen the introduction of various lightweight high-efficiencyanchors which will, under certain circumstances, hold as much as 100 times theirown weight. Most are recognised by Classification Societies and in view of theirhigher holding power, they are allowed to be of significantly lighter weight.Holding power is proportional to fluke area (or, more correctly, to aspect area) andthey set very well except on bottoms having large amounts of seaweed or rocks. Inthese latter circumstances they tend to skate along the bottom rather than dig in. Itis important to bear in mind that although with lightweights the increased holdingpower of a bigger anchor comes primarily from the increase in fluke (blade) area,not weight, it must have weight to penetrate. Too small an anchor will beineffective. There are two basic types with a number of variations and at least onepatented design which is an amalgam of design features from the two.Page 4
Plough Anchor (Fig. 12)Developed in 1933, the stockless plough anchor is remarkably effectiveand in its heavier sizes penetrates kelp and seaweed, shell and overlyinggravel better than most lightweights. It is, like all lightweights, extremelyefficient in mud and sand, and once buried will remain so even thoughthe direction of pull changes with wind or tide – thanks to the angledhinge on the shank.Cruising Anchor (Fig. 13)Anchors generally known as cruising anchors are all variants on theoriginal 1939 Danforth design. With its wide, flat and sharp flukes thistype of anchor readily digs itself into mud and sand when it is heavyenough. It has a stock located at the head (‘crown’) which gives initialstability and alignment to help it dig in. Crown design is such that itoffers little resistance both during the burying operation and also when itis being broken out again. It has the advantage of folding flat for deckstowage.MOORING ANCHORSAlthough the types of anchors described previously are often employed forpermanent moorings, an anchor specifically designed for the job is a far betterproposition. In general it will be cheaper, more ruggedly built, and with few if anyprojections which can be fouled. It is far more efficient than a concrete block, whicheven when buried will only hold about its own weight, and of course it is mucheasier to handle.Mushroom Anchor (Fig. 14)The traditional mushroom anchor has been popular for many years foruse on a mud bottom. It takes a firm hold and remains fixed underadverse conditions. The design is such that when successive strains areapplied it oscillates and creates suction, thus continuing to bury itself inthe mud.Single Arm Mooring AnchorA single arm mooring anchor prevents fouling of other vessels at lowtide and should have a shackle or hole at the crown to facilitate removaland for securing a marker buoy when desired. The most basic is in effecta one-armed fisherman anchor, and suffers from the fact that its palmlacks sufficient area to hold well. The A.M.12 is a single fluke anchordeveloped by the Admiralty for permanent Navy moorings. It has provento be highly successful, combining weight with a reasonable fluke areaand has led to a number of cheaper variants, often sold as proprietorydesigns. The Bradney mooring anchor (Fig. 15) is a high-efficient typewith a particularly large fluke area generating very high holding power. Itdigs in well but like all lightweights, unless it can be inserted manually itneeds a reasonable weight for the initial penetration.Page 5
3. CHAINS AND OTHER COMPONENTSToday the range and variety of chains and fittings is probably wider than everbefore and to compound the selection problem almost all components areavailable in various grades. Different strengths for otherwise identical items areachieved through the use of different steels and heat treatments, some more suitedto the marine environments than othersSTRENGTHSChains and fittings are manufactured in different strengths for specific applications,and the strongest component is not necessarily the best for the job in hand. Itcould be unsuitable for galvanising, or made from a steel which corrodes morerapidly, and it may be disproportionately expensive. As will be seen later, weight isas important as strength in moorings and the lowest and cheapest strength gradeusually offers the best combination of properties. Internationally, there arestandards covering chains and most fittings and these recognise the followinggrades: Grade 30 (3 or L)This is the lowest grade with components made from mild steel without heattreatment and strength approximating to that of the now virtually unobtainablewrought iron.Grade 40 (4 or M)Normally manufactured from plain carbon steels and heat treated, this is thelowest grade recommended for lifting applications.Grade 60 (6 or S)This grade has been largely superseded by grade 80 and is likely to be withdrawnfrom the International Standards series.Grade 80 (8 or T)The highest strength in normal use; components are usually made from alloysteels and hardened and tempered.Chapter 8 provides more detailed information on these various grades and theirsuitability for marine applications.CHAINSWith the exception of stud link chain cable, chains are generally supplied in thegrades detailed above. Stud link chain is normally supplied in grades mild steel U1,special quality U2 and extra special qualit
(Danforth) anchor is an example of this type still very popular today. Modern small boat anchors have all been developed to dig into the seabed when subjected to a horizontal pull. Designs are available which offer enormous holding power for their weight – but they must still have sufficient weight.
May 02, 2018 · D. Program Evaluation ͟The organization has provided a description of the framework for how each program will be evaluated. The framework should include all the elements below: ͟The evaluation methods are cost-effective for the organization ͟Quantitative and qualitative data is being collected (at Basics tier, data collection must have begun)
Silat is a combative art of self-defense and survival rooted from Matay archipelago. It was traced at thé early of Langkasuka Kingdom (2nd century CE) till thé reign of Melaka (Malaysia) Sultanate era (13th century). Silat has now evolved to become part of social culture and tradition with thé appearance of a fine physical and spiritual .
On an exceptional basis, Member States may request UNESCO to provide thé candidates with access to thé platform so they can complète thé form by themselves. Thèse requests must be addressed to esd rize unesco. or by 15 A ril 2021 UNESCO will provide thé nomineewith accessto thé platform via their émail address.
̶The leading indicator of employee engagement is based on the quality of the relationship between employee and supervisor Empower your managers! ̶Help them understand the impact on the organization ̶Share important changes, plan options, tasks, and deadlines ̶Provide key messages and talking points ̶Prepare them to answer employee questions
Dr. Sunita Bharatwal** Dr. Pawan Garga*** Abstract Customer satisfaction is derived from thè functionalities and values, a product or Service can provide. The current study aims to segregate thè dimensions of ordine Service quality and gather insights on its impact on web shopping. The trends of purchases have
Chính Văn.- Còn đức Thế tôn thì tuệ giác cực kỳ trong sạch 8: hiện hành bất nhị 9, đạt đến vô tướng 10, đứng vào chỗ đứng của các đức Thế tôn 11, thể hiện tính bình đẳng của các Ngài, đến chỗ không còn chướng ngại 12, giáo pháp không thể khuynh đảo, tâm thức không bị cản trở, cái được
Le genou de Lucy. Odile Jacob. 1999. Coppens Y. Pré-textes. L’homme préhistorique en morceaux. Eds Odile Jacob. 2011. Costentin J., Delaveau P. Café, thé, chocolat, les bons effets sur le cerveau et pour le corps. Editions Odile Jacob. 2010. Crawford M., Marsh D. The driving force : food in human evolution and the future.
Le genou de Lucy. Odile Jacob. 1999. Coppens Y. Pré-textes. L’homme préhistorique en morceaux. Eds Odile Jacob. 2011. Costentin J., Delaveau P. Café, thé, chocolat, les bons effets sur le cerveau et pour le corps. Editions Odile Jacob. 2010. 3 Crawford M., Marsh D. The driving force : food in human evolution and the future.
