CHAPTER 7ANCHORING, MOORING, AND TOWINGUpon completing this chapter, you should be able to do the following:1.Describe and identify anchors and their related appendages.2.Describe the standard methods for anchoring and mooring ships.3.Describe the procedures for rigging and unrigging for towing a ship and for beingtowed.State the basic rules for adjusting lines during the tow.4.Identify and describe the principal types of salvage.LEARNING OBJECTIVESINTRODUCTIONFederal Supply Catalog lists standard sizes from 3/4 toIn chapter 4 we discussed the procedures involvedin tying a ship up to a pier.In this chapter, we discusshow to anchor a ship and moor it to a buoy.We alsobriefly cover towing and salvage.4 3/4 inches.Wire diameter is measured at the end and alittle above the center line of the link.The length of astandard link is 6 times its diameter; its width is 3.6times its diameter.All links are studded; that is, a solidpiece is forged in the center of the link.Studs preventANCHORSthe chain from kinking and the links from pounding onadjacent links.Although several types of anchors are in use aboardNavy ships, mine countermeasures ships use alightweight-type (LWT) anchor called the Danforth(figure 7-1).IDENTIFYING ANCHORSEach anchor of over 100 pounds ordered by theNaval Sea Systems Command is assigned a serialnumber, which is cast or cut into the anchor before it isdelivered.Serial numbers are found on the shank oflightweight anchors.
These numbers must be recordedin the ships anchor log.If you receive a new anchor, becertain to record the proper numbers.Do not confusethese numbers with other figures, such as the weight ofthe anchor.CHAIN AND ITS APPENDAGESAll Navy ship anchors are connected to some lengthof anchor chain.
Modem Navy anchor chain is made ofdie-lock chain with studs.The size of the link isdetermined by its diameter, called wire diameter.TheFigure 7-1.Lightweight-type (LWT) anchor.7-1Heavy-duty and high-strength die-lock chains arephysically similar to some of the smaller sizes ofstandard die-lock chain but have higher breakingstrengths.
Size for size, the links fit the same wildcat(windlass drum).Chain NomenclatureA chain is made of many parts besides links, and avariety of equipment is used to maintain the chain.Thefollowing paragraphs describe a chain and its associatedhardware:STANDARD SHOTS.The lengths of chain thatare connected together to make up the shipsanchor chain are called shots.
A standard shot is15 fathoms (90 feet) long.Each shot of chainusually bears a serial number, either stamped orcut at the time of manufacture, on the inner sideof its end links.If an end link is lost or removedfrom a shot, this identification number should beeither cut or stamped on the inside of the new endlink of the altered shot.DETACHABLE LINKS.
Shots of anchorchain are joined by a detachable link, shown infigure 7-2.The Navy type of detachable linkconsists of a C-shaped link with two couplingplates, which form one side and the stud of thelink.A taper pin holds the parts together and islocked in place at its large end by a lead plug.Detachable link parts are not interchangeable, somatching numbers are stamped on the C-link andon each coupling plate to ensure identificationand proper assembly.
You will save time andtrouble trying to match these parts if youdisassemble only one link at a time and clean,slush, and reassemble it before disassemblinganother.
When you reassemble a detachablelink, make sure the taper pin is seated securely.You can do this by driving the pin in with a punchand hammer before you insert the lead plug overthe pins large end.Detachable link toolbox setscontain tools and parts, including spare taperpins and lock plugs, for assembling anddisassembling links and detachable end links.Figure 7-2.Detachable link.7-2Figure 7-3.Chain swivel.BENDING SHACKLE.A bending shackle isused to attach the anchor to the chain.CHAIN SWIVEL.
A chain swivel (fig.7-3) isfurnished as part of the outboard swivel shot.
Itminimizes kinking and twisting of the anchorchain.OUTBOARD SWIVEL SHOTS.Standardoutboard swivel shots (fig.
7-4), also termedbending shots, consist of detachable links,regular chain links, a swivel, an end link, and abending shackle.
They are fitted on most vesselsto attach the anchor chain to the anchor.Theyalso make it possible to stop off the anchor andbreak the chain between the windlass and theanchor.The taper pins in the detachable links inthe outboard swivel shot are additionallysecured with a U-shaped, stainless steel, wire-locking clip (sometimes called a hairpin).
Thishairpin, inserted in holes drilled through thecoupling plates, engages a keyway or groove onthe taper pin.(See figure 7-2.)RIDING, HOUSING, AND TOWINGCHAIN STOPPERS.Chain stoppers are usedto hold the anchor taut in the hawsepipes, to rideat anchor, or to hold the anchors when the anchorchain is disconnected for any reason.Riding andFigure 7-4.Outboard swivel shot.7-3Figure 7-5.Chain stopper.housing chain stoppers (fig.
7-5) consist of aturnbuckle inserted in a short section of chainwith a slip or pelican hook attached to one end ofthe chain and a shackle at the other end.Thehousing stopper is nearest the hawsepipe, theriding stopper is farther aft.These stoppers aresecured by the shackles to permanent pad eyeson the vessels deck.When in use, a stopper isattached to the anchor chain by straddling a linkwith the tongue and strongback of the pelicanhook.Special housing chain stoppers, such asthe devils claw or the paw1 type of stoppers,normally are used with horizontal windlassesand where space limitations do not permit use ofNavy standard stoppers.
Although stoppersalone are more than adequate for holding theanchor, they should be backed up with thewildcat brake.Upon anchoring, you should firstset the wildcat brake band, then set the stopperstight, making sure you equalize the tension onthem, so that one is not loaded more than theother.The wildcat should be left disconnectedfrom the windlass.
A Navy standard chainstopper is shown in figure 7-5.Towing chain stoppers are similar to riding andhousing chain stoppers, except that towing chainstoppers have locking plates added.(See fig.
7-6.)These locking plates prevent the towing chain stopperfrom unscrewing when subjected to the shock loadingFigure 7-7.Mooring shackles.Figure 7-8.Mooring swivel.of the towing hawser.
Towing chain stoppers should beused whenever the ship is being towed.MOORING SHACKLES.Mooring shacklesare forged steel shackles (fig.7-7) that are usedto attach anchor chains to mooring buoys.Allmooring shackles, regardless of size, have astandard mortise (opening) of 7 inches.Mooringshackles should not be used for any otherpurposes.MOORING SWIVELS.Forged steel swivels,with two links attached at each end (fig.7-8, areused to moor with two anchors.They areinserted in the chain outboard of the hawse andkeep the chain from twisting as the ship swings.Mooring swivels should be attached in the chainFigure 7-6.Anchor chain stopper modified for towing.7-4sizes of chain.wrapped securely around each stud.At the 30-fathomThe bitter end of the anchor chain is secured to a padANCHORINGThe ships First Lieutenant is in charge on theforecastle while the ship is anchoring and weighinganchor.
Aboard most ships, the First Lieutenantsassistants are the ships Boatswain and ChiefBoatswain.In their absence, the senior PO of thedivision responsible for the ground tackle is the FirstLieutenants assistant.An EN (Engineman) is present tooperate the anchor windlass, and an EM (ElectriciansMate) must be in the anchor windlass room to take careof any electrical failure.The First Lieutenant has atelephone talker, whose duty is to relay orders andinformation between the forecastle and the bridge.
ThePO in charge of the anchor detail musters the detail andensures that all necessary gear is available.SeveralSeamen, whose duties are discussed later, are alsorequired.Necessary equipment is as follows:Detachable link toolbox setChain stopper wrenchChain cable jack or anchor barMaulAnchor buoy and lineOn ships with two wildcats, both anchors are madeready for letting go.
While this is being done, thetelephone talker receives from the bridge suchinformation as the anchor to be used, depth of water,type of bottom, scope of chain to be used, and any otherinformation pertinent to the operation.The exact procedures for making the anchor readyfor letting go may vary, but the following tasks must beperformed: The First Lieutenant or the petty officer incharge must give a safety briefing.All personnelinvolved in the anchoring evolution must be in theproper uniform; that is, with trouser legs tucked in andwearing safety goggles and hard hats with chin straps.Only necessary personnel may be allowed on theforecastle.The Seaman tending the lead line, inaddition to wearing a hard hat, must wear a safetyharness and life jacket.All personnel should be quizzedabout their jobs, and they must be exact in their answers.The windlass is tested; the anchor in the hawse isfreed.The anchor will be walked out if the ship isanchoring in deep water or if the bottom is rocky;otherwise, the brake is set and the wildcat is disengaged.All but one stopper is taken off, and the anchor buoy isshackled to the chafing chain or pendant.The chainlocker is checked for any loose gear that may becomewedged in the chain pipes or come flying out,endangering the personnel on deck.While the anchor detail gets the ground tackleready, the Quartermasters on the bridge take bearings,and the navigator plots the bearings on a chart andadvises the conning officer of the ships position
.Distances to the anchorage are relayed to the forecastle.In letting go by the stopper, the weight of the anchormust be on the stopper.
The brake will be released onthe command STAND BY.In letting go by the brake, the weight of the anchorwill be on the brake and the stopper with the windlassdisengaged.The stopper will be taken off at thecommand STAND BY.At the command STAND BY, the personnel onthe forecastle are alert and ready, awaiting the nextcommand.When letting go by the stopper, two Seamantake stations at the stopper.
When the command LETGO is given, one Seaman pulls the pin from the stoppertongue.The other Seaman, with a maul, knocks the bailoff the tongue of the pelican hook and steps clear, andthe chain will pass through the hawse with a roar.If the anchor buoy was not stopped off with sailtwine, the Seaman tending it must let it go exactly at thecommand LET GO.On the bridge, the anchor ball ishoisted.The flag is hauled down from the truck, and thejack and ensign are hoisted smartly fore and aft.You will notice that the ship is moving (usuallybacking) when the anchor is dropped.This keeps theanchor chain from piling on itself, damaging the chain,or piling on or fouling the anchor.When the anchor is dropped and hits bottom, thebrake should be set to help prevent piling.Reports aremade to the bridge informing them on the initial statusof the anchor, how much chain is out, what position ittends, and what strain it has on it.The bridge is alsoinformed of whether the anchor buoy is watching.(Thismeans that the buoy has surfaced and marks the locationof the anchor.) As the ship gains sternway, the anchorchain is veered out by the brake about a shot at a time tocontrol the speed of the chain.This is continued untilsufficient chain is out to ensure that the pull on theanchor is horizontal on the bottom.
The brake is nowapplied, and the anchor is set by the ships backing downand riding on the chain.Once the anchor is set and7-7and the stoppers are applied and evened up.The brake istaken off; then the chain is slacked between the windlassfouled, or shod (meaning caked with mud and bottom).or more trolleys should be used, and it is a good idea tothrough the bow chock.A typical arrangement is shownFigure 7-13.Typical bow chafing chain arrangement for being towed.which is used for dropping the tow in case ofemergency.
The other end of the chafing chain is fair-led through a closed chock on the stern.A typicalarrangement is shown in figure 7-14.Since it is logicalto assume that the reason a ship has to be towed isbecause it has lost power, the rigging arrangementaboard the ship to be towed must be laid out so no powerassistance is required.Therefore, practice operationsshould be performed with the towed ship using nopower equipment.Towed-Ship Rigging ProcedureThe towed ship rigs for being towed by breaking theanchor chain inboard of the swivel shot.
The anchor notin use is secured in the hawsepipe by a chain stopper anda preventer made of wire.
The wildcat brake is set up.When the chain pipe has a compressor, it is used to keepthe chain from falling back into the chain locker; whenthere is no compressor installed, a bar through the chainand across the chain pipe can substitute for thecompressor.The chain is then moved over in alignmentwith the bow chock It will be hauled through the bowchock later by the towing hawser as a strain is taken onthe hawser by the towing ship.
The connector fittingsare standard rigging and detachable links of the size ofchain being used.
The towing hawser is either wire,whose size and length satisfy the ships plans, orsynthetic hawser 600 feet long.Attached to the hawseris a messenger made up of 100 fathoms of 3-inch lineand 50 fathoms of 1 1/2-inch line.(For a lo-inchcircumference or larger hawser, use the 4-inch in placeof the 3-inch.) Two 100-fathom lengths of 6-thread or9-thread line are attached to the 1 1/2 line and runoutboard on both sides of the ship.
Then the 6-threadline is attached to the shot line, reducing the weight onthe shot line while the messenger is passed to thereceiving ship.
The hawser and messenger are faked outand stopped off to a strongback, with turns of 21-threadline running over a chop block to provide constantcontrol while the hawser is paid out.These stops are cuton command as the hawser pays out.
A retrieval line isconnected to the anchor chain end of the towing opera-tion to retrieve the towing hawser.The same procedureis followed on the towing ship, except that the pelicanhook is rigged to the hard point, and the chafing chain tothe pelican hook, fair-led out the stem chock.You willnotice that we have referred to the ship to be towed asbeing the provider of the rig.
Which ship ultimatelyprovides the initial hawser is a command decision, andcircumstances will be different in each case.Figure 7-14.Typical stern chafing chain arrangement fortowing.When both ships hawsers are used to increase thelength of the tow to 1,200 feet (fig.7-15, one ship willtogether with a pear-shaped detachable link, then payout the hawser as the other ship goes ahead, taking upthe slack as it goes, until all the hawser is out.Whenonly one ships hawser is, the ship receiving the othershawser connects it to either the anchor chain, brokenforward, or the chafing chain, rigged aft.The messenger is secured to the towing hawser asshown in figure 7-16, view A; or if a wire hawser is to beused, it may be modified as in view B.
If desired, a thirdextension to the messenger, and a shackle used to makethe connection between the messenger and strap, whichis secured to the hawser as in view A.Approaching the TowThe position the towing ship takes in relation to thetow during the approach depends on which vessel driftsfaster.When the towing ship drifts faster than the tow,the towing ship takes position forward and to windwardWhen the tow drifts faster, the towing ship takesposition ahead and to leeward.
The idea is that one shipdrifts past the other, allowing more time for passing andhooking up the towline.The towing ship alwaysensures there is plenty of room to maneuver.
If a normalclose approach cannot be made, because of seabuoyed with life jackets and floated down to the tow.Often, however, the approach is close enough to useheaving lines, so there should be three or four heavinglines on deck, as well as a line-throwing gun and bolos.Figure 7-15.Towing hawser arrangement.7-12Figure 7-16.Method of securing messenger to towline.Passing the RigThe end of the towline messenger is passed as soonas possible to the towing ship.During the approach,personnel on the towing ship are stationed at intervalsalong the deck to receive the towline messenger.Oncethe messenger is received, the end is led through thestem chock and run forward.
You may take themessenger to a capstan, but this method is much slowerthan heaving it in by hand until a heavy strain is taken.The final hauling of the towing hawser is usually doneby the capstan.
Once the end of the towing hawser isaboard, the seizing that secures the coupling to themessenger is cut, and the towed ships hawser isconnected to your hawser.A stopper is bent onto thehawser; the messenger is removed; and the towlines arehooked up but not yet deployed.The towing ship putson turns sufficient for steerageway and continues at thissteady speed until the towline is completely taut.Thisslow speed deploys the towline off the towing ship, in aslow orderly fashion, until all the faked out line is off thedeck and the chafing chain has been hauled through thestem chock.The added tension hauls the remaining towline offthe towed ship until its anchor chain comes taut.
At thispoint, the bar is removed from the chain over the chainpipe and the brake on the wildcat is slackened.Thechain is permitted to be hauled out until it clears the bowchock by 6 or more feet.The brake is applied and twotowing chain stoppers are passed onto the chain.While a ship is towing, an emergency releasecapability is required.The chain is veered out to the firstdetachable link and the stoppers are passed forward ofthe detachable link.This will provide access to the linkin case the tow must be released.Getting in StepWhen a ship is towing with synthetic line, nocatenary (line droop) is required.It is not uncommon tohave the hawser completely out of the water; in fact, it isdesirable because it lowers the towing resistance andprevents the line from being damaged by bottomfouling or objects in the water.When heavy seas areencountered, the rule is slow down.At this point, it isimportant to keep the ships in step to lessen the surgeloads.To do this, cast off the stoppers, and adjust thescope to get the vessels in step.The tow must ride sothat it reaches the top of a crest at the same time thetowing ship does.If not, the towing ship might reach thecrest while the tow is in a trough, whipping the towlineout of the water and subjecting it to unnecessary and7-13dangerous strains.(See fig.
7-17.) When the scope isadjusted properly, the chain is secured in the same wayas before.Dropping the TowWhen the ships are dead in the water and the order isgiven, the tow engages its wildcat, casts off the stopper,and heaves in on the chain.When the end of the towlineis aboard, the messenger is bent on the towline.Turnsare taken around the capstan with the messenger, andthe chain is walked out until the strain is on themessenger.
Then the towline is unshackled and easedout.Personnel on the towed ship run in the towline bycapstan or hand.Care must be taken on the towing shipthat the catenary does not become too heavy for thecrew on the towed ship to handle.When a recovery line is rigged on the towing ship,the end of it is led through the towing chock fromoutboard to inboard and hauled in by hand (or, ifne
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