WHOI MOORING OPERATIONS TECHNIQUES OF THE BUOY PROJECT AT THE WOODS HOLE OCEANOGRAPHIC INSTITUTION. Robert H. Heinmi11er, Jr.

Transcription

1 WHO )' MOORNG OPERATONS TECHNQUES OF THE BUOY PROJECT AT THE WOODS HOLE OCEANOGRAPHC NSTTUTON by Robert H. Henm11er, Jr. ~" co ft co.. Õ ru :~ cr :: 3: c: c: == ld-,-c,. ft c: -C WOODS HOLE OCEANOGRAPHr'C NSTTUTON Woods Ho 1 a, Massachusetts August 1976 TECHNCAL REPORT Pr?pared for the Offce of Nava Research under Contract N00014-?4-C~0262; NR and the Natona Scence Foundaton~ Offce for the nternatona Decade of Ocean Exporaton~ under Grant OCE? Reproducton n who e or n part s pep tted for any purpose of the Unted States Governent. n ctng ths manuscrpt n a bblography~ the reference shoud be foowed by the phrase:' UNPUBLSHED MANUSCRPT. Approved for pubc reease;dstrbuton unlmted. Approved for Dstrbuton r-~. Va ent ne Worth ngton, Depa rtment of Phys ca 1

2 Table of Contents Page ABSTRACT... NTRODUCTON. THE MOORNGS. Moorng Confguratons. Computer Desgn.... Hardware nterconnectons. Qualty Control. MOORNG DEPLOYMENT.. General Consderatons Deck Equpment.... Pre-deploymen t Procedures. General Payout Procedure.. ntermedate Moorng Deployment. Surface Moorng Deployment.. Bottom Moorng Deployment. Anchor-Frst Launches... Post-Deployment Procedures. MOORNG RECOVERY General Consderatons. Deck Equpment..... Release of Anchor... General Recovery Procedure ntermedate Moorng Recovery. Surface Moorng Recovery Bot tom Moorng Recovery. Backup Recovery Post-Recovery Procedures. DOCUMENTATON AND RECORDS :' Moored Staton Log.. Eng neer ng Bo log ca 1 Depth Records.. Computer Records Schedulng.. Form ACKNOWLEDGEMENTS.. 61 REFERENCES APPENDX - nstructons for Completng Moored Staton Logs.,/lPPENDX - Glossary..... '". '" '"... t '"

3 ~ 1 ABSTRACT Ths report covers the technques of deployng and recoverng the moorngs used by the Buoy Project at Woods Hole Oceanographc nsttuton. A bref descrpton of the moorngs and assocated hardware s ncluded. Deck equpment s dscussed. Step by step descrptons are gven of the procedures for handlng of the moorng gear at sea durng settng and recovery. Documentaton and qualty control are also dscussed. ~

4 ~ ~ 2 NTRODUCTON Ths report s a detaled descrpton of the technques developed over the years for deployng and recoverng the deep-sea moorngs of the Buoy Project at the Woods Hole Oceanographc nsttuton. These technques are the result of twelve years of evoluton. Although the process of change, of course, wll not stop wth the preparaton of ths document, ths report s an attempt to summarze our operatons technques at the tme of wrtng. t s hoped that t wll be of use to others usng deep-sea moorngs, of the Woods Hole type or any other desgn. Deck operatons are descrbed n consderable detal for those who are not famlar wth the standard methods of workng at sea. n add ton, a glossary of terms s provded n Appendx. For those already famlar wth rggng operatons at sea, the report should serve as a general outlne of the procedures used by the Buoy Project at Woods Hole for moorng operatons. These procedures have been developed to meet the problems of settng and recovery of our own moorngs and are talored to our equpment and our shps. However, the basc approach s adaptable to other moorng confguratons and for use on dfferent vessels. Although the general form of our moorngs wll be outlned, the reader nterested n a more detaled descrpton should consult other 1 Recent desgn changes are ncorporated n the drawngs publcatons. n ths report and dscussed n the text.

5 3 - ~- --" SEA SURFACE ~----- ~~~?-~~~'~~-=-l~~ ~'~~ ~~~~~~~~ TYP.500m. RADO, LGHT, a -l,y RADO FLOAT WRE 20m, WRE 1/211 CHAN WRE (TYP. 20m) TOP BUOYANCY OR 1711 GLASS SPHERES N HARDHATS ON CHAN (TYP. 20 SPHERES). NSTRUMENT WRE WRE 20m. NTERMEDATE BUOYANCY (TYP. 10 SPHERES). WRE WRE 20 m. NTERMEDATE BUOYANCY (TYP.6 SPHERES). WRE : WRE BACKUP RECOVERY BUOYANCY (TYP. 15 SPHERES). RELEASE 5m. CHAFE CHAN : 1:. FG. 1 NTERMEDATE MOORNG

6 4 THE MOORNGS Moorng Confguratons Moorngs used by the Buoy Project fall nto three general confguratons. The ntermedate moorng, shown n Fgure l, s a subsurface moorng wth buoyancy sectons at several depths. The lowest buoyancy secton provdes backup recovery n the event of moorng falure. 2 The depth of the top of the moorng can vary up to w thn 200 meters of the surface or less. The deep-sea surface moorng s shown n schematc form n Fgure 2. A varety of floats has been used. The weght of the anchor vares wth the expected current profle. A sngle cluster of glass spheres near the bottom makes up the backup recovery secton. Some recent desgn changes have been made n the ntermedate and surface moorngs. A twenty-meter wre shot s now placed between a glass-sphere secton and any nstrument or release drectly below t to ease handlng at launch and recovery. On the surface moorngs, the backup-recovery secton s glass spheres nhardhats on chan, nstead of n nets on nylon lne as before. Ths elmnates the need to test spheres because the moorng wll not be endangered f a sphere mplodes on chan. Bottom moorngs, shown n Fgure 3, are used to make near- bottom measurements and for transponder placement and are usually 200 meters or less n length. They have no backup recovery secton and typcally carry only one or two nstruments. Computer Desgn ntermedate and bottom moorngs are desgned usng a computer program. The program s wrtten to be used on the Hewltt-Packard computers avalable on each of the WHO vessels. A smlar computer s avalable ashore. The program, called NOYFB, 3 allows the operator to model any confguraton of subsurface moorng n a wde range of envronmental cond tons. Varous output formats are avalable. For the purposes of ntal moorng desgn, a format s used whch lsts' the depth and tlt of every component of the moorng n a gven current profle. The program s very flexble and allows the operator to rapdly test a seres of moorng confguratons n a varety of current profles. Buoyancy sectons and other moorng components must be adjusted untl the moorng desgn performs wthn specfcatons n the maxmum expected current. The essental parameters are nstrument depth and tlt. For each experment, the scentst specfes a maxmum varaton :

7 5 ~ -. ~ v \1/ ýllght, RADO, a FLOAT ~~-"'~~ :S""'l --~~_ '7~~ - ~~~,~~~ ~-_ ~ SEA SURFACE CHAFE CHAN (TYP. 10m) WRE.. NSTRUMENT WRE.. NSTRUMENT NSTRUMENT WRE ~.. WRE TO 2000 m. NYLON NSTRUMENT NYLON -!, WRE 20m :: CHAFE CHAN 5m ~ NSTRUMENT BACKUP RECOVERY SECTON 1611 OR 1711 GLASS SPHERES N HARD-HATS ON CHAN (TYP. 35 SPHERES) ACOUSTC RELEASE :: ANCHOR TAG LNE - NYLON- TYP. 20m. -- CHAFE CHAN 3m - -, = - FG. 2 SURFACE MOORNG

8 6 ~~~~: ~~X~~5~~ SEA SURFACE ALTERNATE BUOYANCY PACKAGE RADO LGHT, RADO. FLOAT CHAN 4m. BUOYANCY 1611 OR 1711 GLASS SPHERES N HARD-HATS ON CHAN (TYP. 10 SPHERES) CHAN~ FBERGLASS, FRAME WTH 8 SPHERES OR SYNTACTC FOAM FLOAT 11 NYLON, DACON, OR WRE. TYP. 200m... NSTRUMENT ~ NYLON, DACRON, OR WRE. ACOUSTC RELEASE CHAFE CHAN 5m. ANCHOR TAG - NYLON (TYP. 20n8 CHAFE CHAN 3m. ANCHOR (TYP. 1000#) FG.3 BOTTOM MOORNG

9 ! ~ 7 n the depth of the nstruments n profles varyng from no current to maxmum. A typcal specfcaton s for a maxmum of ten meters varaton n 5,000 meters depth. nstrument tlt must be kept low enough so that the calbraton s not affected, less than ten degrees n the case of Savonus-rotor current meters. The program s also used at sea to check last-mnute changes due to bottom depth varatons, etc. to nsure that they do not jeopardze the moorng performance. The program can produce a punched paper tape lstng the moorng confguraton and other parameters for easy access later. These tapes are used for analyss of moorng performance after recovery. Hardware nterconnectons All nterconnectons on the moorngs, between lne termnatons, nstrument bales, etc., are made wth standard hardware (wth the excepton of specal clevs lnks below the rado float and release, for corroson solaton). n order to facltate the launch and recovery operatons, attenton must be pad to the arrangement of these connectons. l ~ All nterconnectons n a moorng nclude at least one oval slng lnk (or master lnk) large enough so that there s plenty of room left after connectng two shackles. Ths slng lnk s used to releve the tenson on the wre, lne, or nstruments durng the deployment and retreval phases whle a thrd shackle or snap hook s beng nserted (stoppng off). Fgure 4 shows several typcal hardware connectons on moorngs. n each case a slng lnk provdes a convenent place to stop off durng launch and recovery operatons. Fgure 5 shows how the slng lnk s used to stop off between two wre shots. Fgure 5a shows the arrangement of hardware, under tenson as on a moor ng. n Fgure 5b, a snap hook on a pennant has been clpped nto the slng lnk. n Fgure 5c, the tenson has been transferred to the stopper, and the upper termnaton s slack for removal, as n Fgure 5d. ~ ~ Slng lnks should be used at vrtually all connecton ponts, ncludng both above and below the nstruments for use n stoppng off. f two nterconnecton pontp are separated by one-half meter or less the slng lnk may be omtted, especally f t would add extra unwanted length between components, snce the stopper can always be attached a half~meter hgher or lower wthout nconvenence. Qualty Control ~ All components used n our moorngs are standardzed. A contnuous program of testng s carred on to nsure that wre and hardware meet specfcatons as to materals, rated breakng strength, and qualty.

10 8 WRE ROPE. BOOT WRE ROPE TERMNATON SLNG LNK 1/2" COTTER PN 316 S.S. BOOT WRE ROPE TO CHAN CHAN 3/8" WRE ROPE WRE ROPE TO WRE ROPE NSTRUMENT SHACKLE 1/2" SLNG LN K 1/2. COTTER PN 316 SS THMBLE SYNTHETC ROPE 3/8" BOOT WRE ROPE D WRE ROPE TO NSTRUMENT SYNTHETC ROPE TO NSTRUMENT ;; FG. 4 TYPCAL HARDWARE NTERCONNECTONS

11 9 Termnatons wth Shackles and S lng Lnk Stoppng-off Hook ::.. :: Hook Engaged Fgure 5 Stoppng Off Tenson on Stopper - Wre Shot Unshackled

12 ~ lo Wre s purchased n bulk and termnated n-house. All termnatons are tested to 60% of rated breakng strength on a test rg as shown n Fgure 6. Wre s nspected durng the measurng and termnatng process for defects n the jacket, etc. Hardware must be nspected after each recovery, ncludng chan, shackles and slng lnks. Any hardware whch has lost most of ts galvanzng must be regalvanzed or dscarded. stanless-steel hardware must be nspected before use to make sure that t s the correct alloy. n some batches of stanlesssteel cotter pns n partcular mld steel pns wll have been ncluded. They may be sorted magnetcally. Supplers must be mpressed wth the mportance of provdng the alloy specfed. Wre samples are routnely cut from the ends of recovered wre. The termnaton and sx to eght feet of wre are saved. A new termnaton s put on the cut end and the sample tested for breakng strength. General Cons der a tons MOORNG DEPLOYMENT Most of our deployments are made by the anchor-last method. That s, the top of the moorng s pad out over the stern wth the shp movng upwnd at a speed of two or three knots. The lne and other gear s pad out under moderate tenson untl the bottom or lower end of the moorng s reached; Fnally, the anchor s attached and allowed to free-fall to the bottom. The anchor-last deployment has the advantage of puttng the least stran on the moorng lne durng most of the deployment. However, n order to place the moorng at a selected locaton careful selecton of the startng pont, lne tenson, and shp's speed relatve to the water depth and moorng length are requred. ~ ~ n general t has been found that for a moorng whch s of a length of from eghty to 100% of the water depth (such as near-surface ntermedate moorngs and surface moorngs) t s usually best to start a dstance of about one and one-half tmes the water depth downwnd from the moorng locaton. Selecton of a startng pont s, perhaps, more of an art than a scence and nvolves a knowledge of how the vessel wll be nfluenced by sea and wnd durng the launch perod. Because of ths, usng the same vessel consstently on successve cruses s an advantage.

13 11 TO PUMP HYDRAULC PSTON TENSOMETER TERMNA non ALUMNUM REEL BOLTED TO FLOOR- UPPER FLANGE REMOVED. FOUR TURNS OF WRE AROUND REEL :: :: - FG.6 SETUP FOR TESTNG OF WRE ROPE TERMNATONS

14 l2 The dstance the shp goes durng deployment wll also be affected by the moorng confguraton. f a moorng contans more components than usual or peces of equpment whch are lkely to be dffcult to assemble on the moorng, thus delayng the payout process, more dstance should be allowed. Conversely, f a moorng has one or more elements on t whch wll provde hgh drag, such as an unusually large surface float, the shp must proceed at a lower speed for a gven lne tenson durng launch and less dstance wll be covered. Of course, f the moorng s to extend through only a fracton of the water depth t wll be launched more quckly and wth shorter dstance covered. Surface currents along the drecton of travel wll generally provde a constant set whch can be easly allowed for. Allowance for all the other factors mentoned depends upon judgment ganed only through experence. A savvy shp's bosun or mate can be extremely helpful on an unfamlar vessel. f n doubt as to the dstance to be run t s better to err on the sde of a startng pont too far away. f the moorng s not ready to be dropped when the locaton s reached there s no turnng back wthout the danger of puttng knks n the moorng. Whereas, f the moorng s ready but the ste has yet not been reached the moorng strng can be smply towed nto poston. f t s desred to place the moorng at a partcular depth (as opposed to a partcular locaton regardless of depth) t may be desrable to move the shp along the approprate depth contour lne rather than upwnd. Steamng upwnd, of course, provdes the best control over the shp, partcularly at the low speeds nvolved. However, ths advantage may be offset by the dffculty of gettng the moorng at the desred depth as the shp steams across the contour lnes. Smlarly, f a strong surface current exsts n a drecton dfferent from that of the wnd, t may be desrable to move nto the current rather than upwnd. n many cases some compromse wll be made between combnatons of wnd, current, and depth contours. The drecton of the launch run may be nfluenced also by the necessty of avodng moorngs already exstng n the mmedate area. :: :; Correctons may be made n the drecton of the shp as the launch progresses and envronmental condtons change, or prevously unknown factors affect the shp's track, such as a set by the current. Course changes of up to nnety degrees may be safely made provded that adequate tenson s mantaned on the moorng. However, radcal changes may cause problems wth the lead of the lne aft and t s preferable to acheve large changes n small stages every several mnutes, f possble, allowng the moorng to come more nearly aft after each change.

15 13 The shp's speed wll vary durng the launch process. As more and more moorng gear s strung out aft, the speed wll slowly drop f t s not adjusted. Tenson on the lne as t pays out s the decdng factor. Tenson should be mantaned at 200 to 300 pounds to prevent the possblty of knkng or tanglng n a slack lne. Too hgh a tenson may cause damage to the wre jacket or to synthetc lne. Fgure 7 shows a calculated curve of tenson versus shp's speed durng launch for a typcal ntermedate moorng, along wth data from an actual launch. Durng perods when the payout of lne s halted, such as whle the nstruments are beng nserted, the shp may have to be slowed to avod the buld-up of excessve tenson. t s mportant to antcpate these perods snce there s a tme delay whle the shp s losng way. For a moorng 5,000 meters long, a typcal deployment wth ths technque takes about one and one-half hours. n general, a smooth and successful launch s the product of careful plannng and preparaton. Once the launch has started, any major delay may cause the moorng to be badly postoned and could resul t n a moorng falure. Those shp's crew and offcers partcpatng should be thoroughly brefed. All equpment and tools should be lad out beforehand, ncludng equpment to cope wth the occasonal crss. A checklst may be desrable. 4 Deck Equpment ~! Several tems of deck equpment have been bult or acqured at Woods Hole for the settng and recovery of moorngs. All of these peces of gear are nstalled aboard shp for a buoy cruse and removed for servcng between cruses. Although when necessary some types of permanent shp's gear such as trawl and hydrographc wnches and capstans have been used, t has been found that the extra expense and trouble of usng specalzed gear s offset by havng wnches and other equ pment well su ted to the job and n known good condton, ready when needed. t also elmnates the necessty for havng an addtonal member of the shp's crew avalable, on those vessels where shp's gear must be operated by shp s personnel. However, for a small moorng group havng specalzed wnches may not be possble or desrable due to the expense. The launch wnch s a smple arrangement of two shafts wth heavyduty brakes, facng aft. t has no power and s used only to payout the moorng lne under tenson, from reels mounted on ether shaft (Fgure 8). All wre and synthetc-lne shots are measured r termnated, and wound on small alumnum reels n the lab ashore. These reels, shown n Fgure 9, wll ft on the shafts of ether the launch or recovery wnches

16 RBS FOR 3/16" WRE -c 3000 ~'- ~ ~ l CALCULATED FOR MOORNG #488 FOR MOORNG #542 ACTUAL DATA 1000 ::.: :; FG WATER SPEED (KNOTS) 7 LNE TENSON VS TOW SPEED (From Walden, 19754) 6

17 "" u ~ 8 ~ :,0.(1 "'" ~j ~~~ -- ~g-q ~Ol.. '" N ~g-)( n'f!! :: / ~-.-:-_.-._. / ~."" o. 2" ~ ~ r~~ ~o" ~~ Q~ a: Q) ~ o.,- :.. u :.,- ~. :: ~ : = -

18

19 =\ l7 and have a separate secton on one sde separated from the man part of the reel by a flange. A wre taglne s passed through a hole n the core n ths separate secton and a fttng s swaged on nsde the core to permanently attach t to the reel. The outer end of the taglne has a swaged eye. To wnd a shot on a reel, the end of the shot s shackled to the taglne and the taglne, fttngs, and termnatons are wound on the core nsde of ths secton before the major part of the shot s passed through a gap n the flange to the man secton of the drum and wound on. n ths way the bulky termnatons are kept separate from the man body of the wre or synthetc lne and damage to the lne, wound under tenson, s avoded. A slng lnk s always used between the tag lne of the moorng shot. Occasonally a number of short shots must be stored. To save reels several of these may be connected together and wound on one reel. n ths case the termnatons wll be too bulky to all be stored n the extra secton. Termnatons and fttngs may then be wound on the drum proper but must be carefully padded by canvas wrappngs or layers of heavy rubber sheetng to prevent damage to the lne wound on top of them. f two adjonng shots are to be launched wthout any components (nstruments or buoyancy package) nserted between them, they may be connec~ed on the reel wth the safety anchor shackles used n the fnal moorng confguraton. The cotter pns should be left out, to avod cuttng synthetc lne or damagng wre jacketng, and nstalled later n the launch process after the termnatons have come off the reel. A slng lnk should be ncluded between the shots. A roller farlead s used at the stern to prevent damage to lne and nstruments durng launch. t conssts of a sx-foot long roller sx nches n dameter mounted horzontally at the stern. ts shaft fts n bearngs on brackets welded to the edge of the deck. At ether end, port and starboard, s a three-foot hgh vertcal stanchon to prevent the lne from movng to the sde off the roller. Both roller and stanchons are covered wth a soft materal. Fgure LO shows roller and stanchons n place. :: = Sheets of plywood are lad on the deck between the launch wnch and the stern roller and are held down wth round-head bolts to mnmze projectons. Ths plywood provdes a smooth surface for the nstruments,to slde on. t extends aft to almost touch the surface of the roller ånd an effort s made n mountng the roller to make the plywoodlroller transton as smooth as possble, wth the upper surface of the plywood and the top of the roller at the same level. Several types of tedowns and cleats are used for stoppers. f adequate permanent cleats are avalable on the vessel they are used. f they are not avalable, two or more portable cleats are used. These are standard cleats, welded to a plate whch s then bolted to the shp s

20 :: ::

21 ~ 19 deck n a convenent spot, usng the deck holddowns avalable on all of the nsttuton s vessels. An eye at the after sde of the wnch base provdes an attachment for a snatch block. A dacron lne wth a safety hook on one end s led from a cleat through the snatch block and aft, to provde a means of stoppng off between lne shots (Fgure ll). Avalable at the start of the launch are two dacron (to mnmze stretch) stopper lnes wth chan grabs on the ends, wth a cleat assgned to each, for payng out the glass-ball sectons of ntermedate moorngs. The lne through the snatch block may be used for one of these, wth the snap hook temporarly replaced wth a chan grab. Pre-Deploymen t Procedures The frst step n preparng for moorng deployment s to fnd a spot close to the desred ste wth an adequately flat bottom, partcularly f the depth s crtcal. A trade-off may be nvolved between poston, depth and ease of deployment. The basc moorng desgn s done ashore. However, n areas where the depth s not accurately known beforehand, an adjustable shot of synthetc lne may be desgned nto an approprate place n the moorng (usually below the nstruments). Once a ste has been selected and ts depth determned, a computer run s made to determne the fnal length of the adjustable shot. Ths shot s then cut and termnated wth an eye splce on a thmble. f the bottom s very flat and the depth was known beforehand, no adjustment may be necessary. A fnal workng drawng s prepared of the moorng as t s to be launched. 9 ~ A schematc dagram of the moorng should be avalable on deck at launch. Frequent reference to t wll nsure that all component tems are nserted nto the moorng n proper order. n addton, whle a secton s beng pad out the dagram can be used to antcpate and layout for deployment the next components. f enough personnel are avalable, t s mportant to assgn to one person the tasks of keepng the moored staton log sheet and callng out each succeedng component to be launched (see page 59 for detals on Moored Staton Log Sheet). All gear to go on the moorng should be at hand before the deployment s started. Smlarly, all deck gear necessary to the operaton should be readed. = Once preparatons are complete the shp proceeds to the startng pos ton for the launch run. 9

22 20 STANCHONS WNCH r~ ANCHORS VEW OF STERN FROM ABOVE FG. 11 DECK ARRANGEMENT FOR DEPLOYMENT

23 d 21 General Payout Procedure The followng procedures are used for the deployment of both surface and ntermedate moorngs. Specfcs for each type are dscussed separately. Lne s pad out from alternate sdes of the launch wnch. As the end of a shot s reached the wnch s slowed and the termnatons and taglne are allowed to pay slowly off the drum. As the termnaton to the taglne comes just off the drum, the snap hook of the man stopper s snapped nto the slng lnk between the wre shot and the taglne (Fgure l2a). The nboard end of the stopper s made fast to a cleat and the taglne s pad out untl the tenson s on the stopper (Fgure l2b). The taglne s then unshackled from the slng lnk. The taglne s wound back on the reel and the empty reel removed from the wnch shaft (Fgure l2c), and the next full reel put on. When an nstrument s to be nserted, ts upper end s then shackled to the slng lnk. (Remember - the top of the moorng s pad out frst.) The lower end s shackled to the upper end of the wre shot on the next full reel (Fgure l3a). The slack lne s hauled onto the second reel and the brake locked. The stopper lne s slacked untl the tenson s on the reel and the stopper hook s removed (Fgure l3b). One person s assgned to handle each stopper. lne. The nstrument s pad out slowly over the stern roller and nto the water. nstruments should be tended carefully as they go over the roller to make sure they do not hang up and cause the lne from the nstrument to the wnch to go slack. mpacts of nstruments aganst the deck or stanchon must be avoded. f two shots have been shackled together on a reel and no nstrument s to be nserted the lne does not need to be stopped off. The termnatons can be stopped just aft of the wnch whle the cotter pns are nserted. Payout s then resumed. When an nstrument s to be nserted between two shots on the same reel the top shot s stopped off as above and the nstrument connected. However, payout resumes wth the next shot on the same reel nstead of gong to the other reel. ~ Fgure 14 shows the steps n anchor launch. When the lower end of the moorng s ready to go overboard the anchor release s attached to the lower end of the last shot (or the lower end of the backup recovery secton, to be descrbed later, see Fgure l4a). The anchors are placed at the/starboard ral before the shp leaves port. On all nsttuton v~s;els a~on o~~~~ulwark~ s removable at ths pont. On othèr--vessels the anchor may~pcked up by the crane j

24 22 ROLLER..MOORNG LNE /20. STOPPER LNE o WNCH CL EAT h SNAP N STOPPER HOOK PAY OUT REEL TAG LNE f2b. o t~ TENSON ON STOPPER o UNSHACKLE REEL TAG o f2c. t~ REMOVE REEL o PREPARE NEXT SHOT TOP VEWS OF STERN FG. /2 STOPPNG OFF WRE SHOT - REEL CHANGE

25 MOORNG LNE NSTRUMENT STOPPER - o WNCH t~ SHACKLE N NSTRUMENT SET BRAKE ON REEL SLACK STOPPER 13b =1 t~ = - ~ = _ o TOP VEWS OF STERN TENSON ON REEL REMOVE STOPPER FG. 13 NSERTON OF NSTRUMENTS J!

26 24 TOP VEWS OF STERN ATTACH RELEASE ATTACH ANCHOR TAG ~MOORNG LNE AND CHAFE CHANS ~t /40 14b LEAD SLP LNE ~l J. t CHAN TO RELEASE SL NG LNK SHACKLE SHACKLES SLNG LNK NYLON TAG LNE " t TO ANCHOR 14c s:? LNE 14d FG. /4 LAUNCH OF RELEASE AND ANCHOR f - ì f

27 TENSON ON SLP LNE REMOVE STOPPER ANCHOR TAG TOP VEWS OF STERN ROLLER D 25 PAY OUT SLP LNE CHAN -.! 14e ~t!4f TENSON ON ANCHOR -. -HAUL N SLP LNE, DROP ANCHOR c? o~ () = TURN\ SH P 1 t4g t4h FG. 14 con. LAUNCH OF RELEASE AND ANCHOR

28 26 before the launch begns and slung over the ral on a heavy nylon strap; to be cut away at the proper moment. The anchor chafe chan, nylon tag lne and release chafe chan are all shackled together. The lower end s shackled to the anchor brdle and the strng s led around the quarter outsde the bulwarks and brought n through the stern roller. The upper end of the chafe chan s shackled to the release rng (Fgure l4b). An extra slng lnk s attached to the slng lnk separatng the chafe chan and tag lne, as shown n detal n Fgure l4c.a slp lne s now run from the eye at the base of the wnch, through the extra slng lnk, and back to the wnch where t s wound on an empty reel wth end free on the nsde (Fgure l4d). The slp lne s then hauled up tght and the brake set on the wnch. The stopper lne s slacked off untl the full tenson s on the slp lne (Fgure l4e). (On smaller vessels there may not be space between the wnch and roller to stretch out the chan and release. n ths case, t s better to use a chafe chan n two peces connected wth two shackles and a slng lnk. The extra slng rng can then be attached at ths stage, a sutable dstance below the release. The procedure s then the same. t s unwse to attach ths rng drectly at the bottom of the release as there s some danger of the end foulng n the release mechansm when t s slpped.) The slp lne s now pad slowly off the reel. The release s eased over the roller whle one person tends the anchor tag lne to nsure that t does not foul (Fgure l4f). The slp lne s pad out untl the moorng tenson s on the anchor, whch has been restraned wth a lashng f necessary. Fnally, the end of the slp lne s allowed to come off the reel and the lne s hauled back clear of the moorng from the fxed end (Fgure l4g). f the slp lne should foul on a cotter pn or some other part of the moorng, under no crcumstances should t be cut free of the shp. f the remnants of the lne foul on the release durng anchor free-fall, they could prevent anchor separaton at recovery tme. f foulng occurs and the slp lne cannot be pulled free, the anchor tag lne should be put on a wnch or capstan and hauled back, the snarl cleared, and the procedure repeated. Once the slp lne s clear and the anchor tag lne taut, the shp s put nto a sharp starboard turn and the speed ncreased to half ahead to buld up tenson momentarly. When the moorng s taut and well clear of the shp the anchor lashngs are cut and the anchor dropped over the sde (Fgure l4h). ntermedate Moorng Deployment Preparaton for deployment of an ntermedate moorng conssts of assemblng the uppermost buoyancy secton on deck, ncludng the rado float. Two stopper lnes wth chan grabs are prepared.

29 27 Launch of the buoyancy secton s shown n Fgure 15. The launch begns wth the shp n poston and movng n the desred drecton at about three knots. One chan grab s fastened nto the chan of the buoyancy secton about twenty feet from the top. The rado float s passed over the stern roller and the stopper slacked carefully to allow the glass spheres to payout (Fgure l5a). Untl suffcent spheres are n the water to provde some drag the spheres wll have to be pushed over the stern.. The stopper s pad out ntl the grab reaches the roller. The second grab s attached near the wnch (Fgure l5b), and made fast on ts cleat. The frst grab s slacked, transferrng tenson to the second (Fgure l5c). The frst grab may now be removed whle the second s carefully pad out (Fgure l5d). When the second grab s at the roller the process s repeated untl the lower end of the secton s reached (Fgure l5e, l5f, and l5g). The lower end may then be attached to the upper end of the wre shot whle beng held on. the stopper (Fgure l5h). The brake s set on the wnch and the last stopper s slacked, transferrng tenson onto the wnch (Fgure l5). Payout then contnues as descrbed above (Fgure l5j). The procedure s the same for each buoyancy secton, ncludng the backup recovery, as t comes up durng the payout. nstruments are nserted and the release and anchor deployed as descrbed n the prevous secton. 1 Surface Moorng Deployment n preparaton for the launch of a surface moorng, the float s placed on the starboard sde of the fantal and fully rgged. The chafe chan s attached. The crane hook s attached to the buoy wth a quck-release mechansm. The upper end of the frst wre shot s led around the outsde of the ral forward and shackled to the chan, or to the lower end of the nstrument f one s to be nserted just below the float (Fgure l6a). f there s to be an nstrument at the lower end of the chan, t s useful to use a slp lne at each end of t to ease t over the sde, as shown n Fgures l6a and l6b. 1 Wth the shp n the start locaton and movng slowly on the desred course, the slack s taken out of the lne leadng to the surface float, whch s then lfted out over the sde (Fgure l6b) and the quck-release hook trpped to place t n the water (Fgure l6c). The lne must now be kept taut by haulng n on the reel as the float moves l

30 28 to f'. FRST GRAB TO ROLLER. SECOND GRAB ON STOPPER t~, 150 ~~.. 15b TOP VEWS OF STERN TENSON ON SECOND GRAB REMOVE FRST GRAB PAY OUT SECOND GRAB 15c 15d ; FG. 15 NTERMEDATE MOORNG DEPLOYMENT TOP BOUYANCY SECTON

31 =! ':\l. TOP VEW OF STERN 29 SECOND GRAB AT ROLLER FRST ATTACHED. TENSON ON FRST GRAB -l /5e /5f REMOVE SECOND GRAB ATTACH WRE PAYOUT d :: ).!5g!5h -",, :: - FG. /5 con. NTERMEDATE MOORNG DEPLOYMENT TOP BOUYANCY SECTON

32 30 TENSON ON WNCH 15 TOP VEW OF STERN l~ + PA Y OUT : 15; : FG. /5 cont. NTERMEDATE MOORNG DEPLOYMENT TOP BOUYANCY SECTON

33 =1 31 FLOAT RGGED ROL L ER FLOAT OVER SDE LOWER NSTRUMENT REMOVE SLP LNES -- /60 /6b DROP FLOA T HAUL N WRE SLACK k FLOAT AFT PAY OUT WRE t ='!6e :: --'1!6d FG.16 SURFACE FLOAT LAUNCH ::.

34 32 aft alongsde the vessel (Fgure l6d). Once the float s well aft, payout of the lne can start. The launch may now proceed routnely, as descrbed n the general deployment secton. As each reel s empted, payout contnues on the other reel whle the empty s removed and a new full reel placed on the shaft. Ths process contnues untl the backup recovery secton s reached. The launch of the backup recovery secton, consstng of glass spheres n hardhats mounted on chan, s the same as that descrbed for the buoyancy sectons of an ntermedate moorng, dscussed n the prevous secton. The release and anchor are deployed as descrbed n the general deployment procedures secton. Bottom Moorng Deployment Bottom moorngs, usually relatvely short and uncomplcated, are generally pad out by hand wthout usng the wnch. The entre moorng s preassembled on the stern, as n Fgure 1 7a. The anchor may be ether at the stern or at the starboard sde, or, f the shp has no openng at the ral, may be slung over the sde on a nylon strap. All nstruments and the release are lad at the roller, upper end aft. Short shots of lne may be faked down carefully just nboard of the nstruments. Longer shots may be put n barrels. f plated or braded synthetc lne s dropped loosely nto a barrel or other open-topped contaner and allowed to reman undsturbed untl launch, t wll payout smoothly wth no snarls. (Tensons are so low n a bottom-moorng launch that the lne may be stopped for a few seconds by hand to clear mnor knks.) wth the shp n poston and movng slowly upwnd the glass spheres, f used, are smply pushed over the stern. f a syntactc foam float or glass-sphere "package" s used, t may be lfted over the starboard sde wth the crane, released and allowed to move aft. n ether case tenson s taken below the frst nstrument by a person (wearng heavy work gloves) who then controls the payout, keepng mnmal tenson on the lne (Fgure l7b). As each nstrument or the release comes up, someone else takes the tenson of the lne below t and the upper lne s dropped over the roller (Fgures l7c, l7d, and l7e). Eventually tenson s passed to the anchor and the anchor s pushed over the stern (Fgure l7f). Anchor-Frst Launches Occasonally t may be necessary to launch a moorng anchor-frst. Ths may be to acheve a precse geographcal poston, place a moorng

35 - RELEASE ANCHOR TOP VEWS OF STERN NSTRUMENT ROLLER 33 PAY OUT GLASS BALLS 17a 17b o TENSON TRANSFERRED TO NSTRUMENT PAY OUT NSTRUMENT f7c 17d o o PAY OUT RELEASE ~ítfltrt ANCHOR DROPPED '- \ \!S, ;-.-'/,...~:t"'..~" =j o :: 17e --~?f o o = J FG. 17 LAUNCH OF BOTTOM MOORNG

36 34 very precsely relatve to one already n place, or to protect a fragle pece of equpment whch mght be damaged by the hgh relatve water speeds of the anchor-last deployment method. n an anchor-frst deployment the moorng s pad out off the recovery wnch over the starboard sde (Fgure l8). The lne goes over a block on the A-frame or crane boom. A stopper wth a snap hook hangs next to the block. (See secton on recovery for a descrpton of ths equpment. ) The anchor, chafe chan, anchor tag lne, and release chafe chan are all shackled together. The upper end of the assembly s shackled to the tag lne on a reel on the wnch and wound on the reel. The wnch s used to pck up the anchor and lower t nto the water. Durng ths part of the operaton, very hgh dynamc loadng on the moorng lne can result from drag on the anchor as the shp heaves or rolls. Ths s partcularly true f the anchor presents a hgh drag profle n the vertcal. f an anchor wth a large horzontal surface area s used t s desrable to launch t tpped on ts sde. The Stmson anchor, for nstance, acts lke a horzontal flat plate. For an anchor-frst launch, one of the three anchor brdle chans may be cut so that t wll le vertcally. (Ths, however, wll reduce ts effectve holdng power on the bottom. An alternatve s to tlt the anchor up on edge and restran t there wth a corrosble lashng of magnesum wre whch wll allow t to assume ts normal poston after several hours n the water. ) Once the anchor s over, the tag lne s pad out untl the upper end of the release chafe chan s at the ral outboard of the block. The snap hook on the stopper s put nto the slng rng (Fgure l8b) and the wnch tag lne slacked to put the tenson on the stopper (Fgure l8c). The lower end of the release s shackled to the upper end of the chan tag (Fgure l8d). The lower end of the short wre shot between release and backup recovery secton s shackled to the release and the shot wound on the reel (Fgure l8e). The wnch takes the tenson and the stopper s removed (Fgure 18f). Ths shot can then be pad out untl the upper end s reached and t s stopped off (Fgures l8g and l8h). Next the backup-recovery secton must be deployed. The lower end of the glass-sphere secton s attached to the top of the wre shot (Fgure l8t). A tag lne (or the next moorng shot) wth a chan grab s secured to the chan a few feet up and the spheres hosted up untl the tenson s taken off the fxed stopper (Fgures l8j and l8k). The wnch s lowered untl the chan grab s at deck level. A chan grab, attached to the fxed stopper hook, s then used to take the tenson, as n Fgure l8~, and the movable stopper, runnng to the wnch, s moved further up the chan and the process repeated (Fgures l8m and l8n). Fnally, the lower end of the next wre shot s shackled to the

37 :: 35 VEWS OF STARBOARD SDE FROM FORWARD ANCHOR N WATER STOPPER ON TERMNATON -, STOPPER WNCH ANCHOR. 18a TENSON ON STOPPER f8b REMOVE TAG LNE ATTACH RELEASE - = 18e f8d! = -" FlG. 18 ANCHOR-FRST LAUNCH

38 36 A TTACH WRE SHOT TENSON ON WNCH STOPPER OFF t 18e PAY OUT TO END OF SHOT ATTACH STOPPER f8f TENSON ON STOPPER REMOVE TAG LNE ~...~o, / f8g 18h ATTACH GLASS BALLS VEWS OF STARBOARD SDE FROM FORWARD CHAN GRAB : WRE SHOT 18 FG. 18 con. ANCHOR-FRST DEPLOYMENT

39 37 HOST UP BALLS WTH CHAN GRAB ON WNCH TENSON ON WNCH ATTACH. CHAN GRAB ON STOPPER 18 18k VEWS OF STARBOARD SDE FROM FORWARD LOWER - ATTACH STOPPER WTH CHAN GRAB 18/ TENSON ON STOPPER - SLACK WNCH TAG a REMOVE SECOND 'BTE' - LFT BALLS WTH WNCH TAG 1, j -, f8m f8n,, ' : REPEAT PROCESS UNT/LL ALL SPHERES ARE OVER THE SDE. 1 FG. 18 cont. ANCHOR-FRST DEPLOYMENT. HANDLNG,OF GLASS-SPHERE SECTONS.

40 38 upper end of the chan and pad out. A smlar procedure s used for ntermedate buoyancy sectons. When nstruments must be nserted the lne s pad out and the fxed stopper hook used to support the moorng by the slng rng (Fgure 19a). The lower end of the nstrument s attached to the wre and the upper end to the next shot (Fgure 19b). The tenson s then taken on the new shot (Fgure 19c) and payout resumes (Fgure 19d). A smlar procedure s used at the end of a reel. The moorng s supported on the fxed stopper whle the reels are changed and the lower end of the frst shot on the new reel s led through the block and shackled to the prevous shot. Much of ths work requres care snce t s done beyond the ral of the shp. Payout contnues n ths manner untl the top of the moorng s reached. f t s a surface moorng the float should be rgged and ready on deck close by the A-frame. The chafe chans, nstrument f any, and tag lne should be attached. When the upper end of the top shot s reached the float s lfted on the quck-release hook on the crane and the tag lne, or lower end of the nstrument, s shackled to the end (Fgure 20a). The wnch tag lne s then pad out untl the tenson s on the crane (Fgure 20b). The wnch tag lne s then removed (Fgure 20c) and the float may be swung out and released (Fgure 20d). For surface-moorng anchor-frst deployments the anchor wll be on the bottom durng the last part of the payout. Thus very hgh tensons can develop f the shp s tendng to drft. f the moorng s an ntermedate moorng the top buoyancy secton may be pad out untl the rado float s reached. The strng may be grabbed wth a quck-release hook through a slng rng just below the rado float and released. There s no pont n settng bottom moorngs anchor frst, normally. The entre anchor-last method takes about two mnutes so the shp doesn't move apprecably. n ether case most of the poston error wll occur whle the moorng s fallng to the bottom. t should be noted that deployment by the anchor-frst method s much slower than anchor-last. f the shp cannot mantan poston durng ths perod, the method may be no more accurate n postonng than the anchor-last technque. n general, moorngs wth no complance,. e., all-wre moorngs wth no synthetc lne, should not be launched anchor frst. Complance n the lower part of the moorng s necessary to reduce dynamc loadng on the anchor durng the early part of the launch and, n the case of a surface moorng, to compensate for shp drft between the tme the anchor bottoms and the float s released.

41 -~~ "1 -, =1 39 A-FRAME OR CRAN7 BLOCK TENSON ON STOPPER ATTACH NSTRUMENT STOPPER _!, 19 a 19b VEWS OF STARBOARD SDE FROM FORWARD TENSON ON WNCH' REMOVE STOPPER = =J f9c f9d! -- FG. 19 ANCHOR-FRST LAUNCH NSTRUMENT DEPLOYMENT

42 40 VEW OF STERN FROM STARBOARD SDE A-FRAME LFT FLOAT ATTACH CHAN TO MOORNG LNE WNCH TAG LNE- (,, ~ ~ CRANE \ FLOAT /' 1 \ (!"" -., -,"' L 1FT F LOA T -,,/' TENSON ON CRANE 20b REMOVE STOPPER LOWER FLOA T NTO WATER RELEASE FLOAT (. ḷ ~ C''"~ Ç) P,4./ 1b 20c FG d ANCHOR-FRST LAUNCH, SURFACE-FLOAT DEPLOYMENT

43 ~ 41 Post-Deployment Procedures mmedately after anchor drop the shp s hove to. Normally the acoustc release s tracked to the bottom and the tme of bottomng noted. (~he transponder range s plotted versus tme on a graph. Anchor bottomng appears as a change n the slope of the lne. Normally, snce the shp s drftng, the range contnues to ncrease after bottomng. The event may not be easly detectable wthout a graph.) A seres of checks are then run on the release and recorded on a separate form. These checks are dscussed n LaRochelle's report on release operatons. 5 J t s mportant to montor the descent of the release. f a falure of the moorng occurs durng the free-fall, t can be detected by ths method. f the descent rate suddenly ncreases, the moorng has. parted above the release. f the release suddenly starts to rse, the anchor tag lne has parted. (Ths occurred on two moorngs n the MODE. 6) experment. n the aftermath of a moorng deployment wth personnel engaged n cleanng up or preparng for the next operaton, t s easy to forget that the moorng could stll fal, allowng all or part of the moorng strng to come back to the surface where t mght not be seen vsually, partcularly at nght, unless someone was lookng for t. Montorng the release descent wll help to guard aganst ths. n addton, a rado recever should be left on for several hours after anchor launch to nsure that the top of the moorng has not separated and resurfaced. Surface moorngs have been known to settle out to wthn a hundred meters of the anchor-drop poston and n any case wll overshoot slghtly before settlng out. t s usually desrable to move a few hundred yards cross-wnd after droppng the anchor of a surface moorng to avod havng the float come too close to the shp. 1 n recordng the poston of a bottom or an ntermedate moorng the poston of anchor drop s usually used. t has been found, both by computer modelng and by experment,7 that the anchor wll settle out at a dstance of between 10% and l5% of the water depth from the anchor-drop poston back towards the drecton from whch the shp was comng durng the payout process. n 6,000 meters of water ths error s usually wthn the error of navgaton. ~ 1 f more accurate navgaton s avalable, and a more precse moorng poston s desred, t may be possble to maneuver the shp drectly over the acoustc release by means of the transponder n order to get a fx. Ths s usually a tme-consung process, however. The water depth at anchor drop s normally used as the moorng depth. Here sgnfcant errors may result, partcularly f the bottom

44 42 s very rough. Agan, f a more accurate depth s desred, some tme may be spent maneuverng over the moorng release for a measurement. For surface moorngs, of course, t s possble to move alongsde the float for a fx and depth measurement. Because of the watch crcle of even a very taut moorng, however, the poston may stll be n error by up to a klometer or more n deep water. At the same tme, a vsual check can be made for damge to the float and whether the lght s operatng. f an ntermedate or bottom moorng has been launched, the moorng desgn s run through the computer n the exact confguraton n whch t was launched, ncludng all last-mnute component substtutons and adjustments. The depth of each nstrument wth zero current profle s computed and recorded on the staton log and a paper tape s prepared wth the component lstng for the moorng. MOORNG RECOVERY General Consderatons Recoveres, whch are prmarly rggng exercses, are generally more straghtforward than deployments. The frst problem, however, may be to fnd the moorng. f a surface-moorng float s not found at the expected locaton a check should be made for the release n case the moorng has parted. f there s acoustc contact the bottom part of the parted moorng can be recovered by frng the release and allowng the backup recovery flotaton to brng t to the surface. f the release s not n the expected locaton the recorded poston may be n error. A comparson should be made between the recorded depth at launch and the depth at the recovery ste, and the orgnal navgaton logs durng the launch checked for mstakes. f everythng checks, a vsual search may be made around the area n case the moorng dragged some dstance. Radar and rado montorng (f the float carred a beacon) may, of course, also help locate t. n the case of bottom or ntermedate moorngs, only the acoustc release s avalable to ascertan the moorng locaton. f an area search has to be made, the hull-mounted acoustc transducer s nvaluable, partcularly f t s drectonal. f no contact s made wth the release, as a last resort a frng commnd may be sent at the best known moorng locaton and a vsuallrado search made for a surfaced moorng on the assumpton that the pngerltransponder part of the release s dead. 2

45 ! 43 n our operatons we commonly get useful transponder ranges of up to eght klometers. Ths wll, of course, vary dependng on the shp, sea state, and condton of the release. Deck Equpment A gasolne-powered wnch (Fgure 2l) wth a sngle shaft, whch uses the same reels as the launch wnch, s used for recovery. The wnch s stuated facng the starboard A-frame. t has an eye wth a stopper chan and hook at ts base. A large block (Fgure 22) s hung from the A-frame on the starboard sde or from the crane boom. An mportant feature of ths block s the wde sheave whch allows suffcent clearance between the cheeks to pass chan and complete termnatons (two shackles and a slng rng). (f the block must be hung from the crane boom, the recovery process becomes a bt more complcated durng perods when the crane must be used to lft floats, etc.) A stopper, consstng of a length of chan wth a snap hook on the end, hangs next to the block. The hook hangs to about a foot above deck level. The arrangement of the fxed deck equpment s shown n Fgure A snap hook mounted on a pole s used to hook onto floats from a dstance over the sde of the shp. Ths s a snap closure hook wth a pece of barstock welded on (Fgure 24a). The pole s of ttanum tubng to reduce weght, and has a socket to hold the hook (Fgure 24b). A pennant attached to the hook has a loop at the nboard end for the crane hook. The hook s snapped nto a pckup rng on the float (Fgure 24c) and the pole removed (Fgure 24d). The tag lne s then lfted wth the crane. A generous supply of stopper lnes and chan-grab hooks s on hand before recovery starts. Deck gear for the acoustc release s descrbed elsewhere. 5,8 Release of Anchor :, Frng of the acoustc anchor release on a surface or ntermedate moorng s usually'done wth the shp at a dstance of about a thrd of the water depth or more to avod the possblty of becomng fouled n the glass sphere buoyancy sectons as they surface. -J Before actuatng the release a seres of checks are run on the release; 5 f the release s extremely balky or f t s dffcult to mantan contact wth t due to poor acoustc condtons or dffculty n keepng the shp n the vcnty of the moorng, such as n very hgh currents, t may be desrable to omt the release checks and fre the release as soon as good contact s establshed. =1

46 ~ 44.. u: -.- :3 tr : -.- r- :: ro :: :: ::

47 ~ =1 :: =1

48 46 TOP VEW OF STERN o A-FRAME ~-- STOPPER BLOCK 230 BLOCK AND STOPPER MAY BE HUNG FROM CRANE BOOM F A- FRAME NOT AVA/LABLE. SDE VEW FROM STARBOARD STOPPER BLOCK SNAP HOOl( :: ~. ~.... ~...., A.... ~..~.....,...,..... V b :: FG. 23 DECK ARRANG MENT. FOR RECOVERY. ' ~

49 47 J Hook Hook on Pole :: :: Hook onto Buoy Pole Removed =1 Fgure 24 Operaton of lc~up Pole

50 48 General Recovery Procedure Haulng of the moorng str ng s done over the starboard sde. The stopper hangng alongsde the recovery block s used to hold the strng whle nstruments are removed or reels changed on the wnch. As an nstrument or cluster of glass spheres comes up to the block (Fgure 25a) the stopper hook s snapped nto the slng rng below the component (Fgure 25b). The wnch s then slacked off untl the tenson s on the stopper (Fgure 25c). The nstrument or sphere cluster s then unshackled from both the upper and lower shots and removed (Fgure 25d). f the reel s to be changed on the wnch the tag lne from the new reel s led through the block and shackled nto the shot hangng on the stopper. f the shot s to be wound on top of lne already on the reel, the upper shot s smply shackled nto the lower shot, n effect becomng a tag lne (Fgure 25e). The tenson s then taken on the wnch and the stopper removed (Fgures 25f and 25g). Haulng then resumes. f a termnaton between two wre shots comes aboard wth no nstruments n between, the termnaton may be hauled through the trawl block and stopped off at the stopper on the base of the wnch, as shown n Fgure 26. The connecton s a lttle easer to work on there. f the termnaton s to be smply wound on the same reel, there s no need to stop off and dsconnect. The cotter pns may be removed and the haulng resumed. snce wre rope s not reused, no partcular care need be taken n wndng termnatons on the reel. Once the termnaton secton of the reel s full, addtonal termnatons are smply lad on top of the wre turns and the wre wound on top. n the case of synthetcs, termnatons are kept from damagng the lne on the reel by wrappng them wth canvas as they go on the reel. The next few turns of lne are then lad carefully on top untl the termnaton s suffcently padded that no damge can occur. Tensons wl usually be relatvely low, makng haulng easy. However, f the wnd s causng the shp to drft at a hgh rate, or f a large component on the moorng s creatng very hgh drag durng haulng, very hgh tensons can result. Care must be taken when wndng synthetc lne under tenson. A great deal of energy can be stored on a reel of stretched lne. n some cases ths has resulted n the welds of the flanges breakng. Even f the statc tenson on the moorng strng s low the runnng tenson may get qute hgh f the moorng s hauled too fast, due to the drag. Once a reel flange s broken, pressure on the retaner on the end of the wnch shaft makes t dffcult and very messy to remove the reel from the shaft.