welding_journal hull repair

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PUBLISHED BY THE AMERICAN WELDING SOCIETY TO ADVANCE THE SCIENCE, TECHNOLOGY, AND APPLICATION OF WELAND ALLIED JOINING AND CUTTING PROCESSES WORLDWIDE, INCLUDING BRAZING, SOLDERING, AND THERMAL SPRAYI

March 2012

Bonus: The American Welder

Marine Construction

and Repair

Do-It Yourself Project

FABTECH Canada Preview New Filler Metal Spec


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CONTENTS32 Undertaking a Complex Underwater Repair

A cargo ship filled with iron ore suffered extensive damagefrom a grounding, but was put back together again by anunderwater repair teamD. Phillips

40 FABTECH Comes to CanadaThis popular all-inclusive fabricating and welding exhibitionopens up to a Canadian audience

43 Welded Aluminum on Ships An Overview As shipbuilding techniques evolved, so did the use of aluminumG. A. Mirgain

48 Build Your Own Campfire GrillThis do-it-yourself project has everything you need to know toget startedB. Pelky

51 New AWS Spec Details Flux Cored and Metal CoredElectrodes

A new filler metal classification system addresses the newgeneration of flux cored and metal cored electrodesD. Crockett

Welding Journal (ISSN 0043-2296) is monthly by the American Welding$120.00 per year in the United Statessions, $160 per year in foreign counper single issue for domestic AWS m$10.00 per single issue for nonme$14.00 single issue for internationaWelding Society is located at 550 NWMiami, FL 33126-5671; telephone (3

Periodicals postage paid in Miami, Ftional mailing offices.POSTMASTER:Send adchanges to Welding Journal, 550 NWMiami, FL 33126-5671.Canada Post: PublicMail Agreement #40612608 Canada sent to Bleuchip International, P.O.London, ON N6C 6B2

Readers ofWelding Journal may make coarticles for personal, archival, eduresearch purposes, and which are noresale. Permission is granted to quotcles, provided customary acknowlauthors and sources is made. Starreexcluded from copyright.

DepartmentsEditorial ............................4 Press Time News ..................6News of the Industry ..............International Update ............1Stainless Q&A ....................14RWMA Q&A ......................2Point of View ....................24Product & Print Spotlight .....Conferences ......................60 Coming Events....................62Certification Schedule ..........6Society News ....................73Tech Topics......................74 Guide to AWS Services ........

Personnel ........................88 American Welder Learning Track ..................96Fact Sheet......................100

Classifieds ......................106 Advertiser Index ................108

65-s Continuous Cooling Transformation Behavior in theCGHAZ of Naval SteelsTransformation diagrams were developed for the coarse-grainheat-affected zone of HSLA-65, HSLA-100, and HY-100 steels

X. Yue et al.

74 -s Developing an Alternative Heat Indexing Equationfor FSW

A heat transfer model was developed to help predict thecorrelation between weld tool geometry and process parametersJ. A. Querin and J. A. Schneider

81 -s Improving Supermartensitic Stainless Steel WeldMetal ToughnessExperiments were conducted to achieve weld metal toughnessimprovements through varying postweld heat treatmentsS. Zappa et al.

89 -s Ultrasonic Wave Assisted GMAWMetal transfer showed improvement with the application of anauxiliary detaching force

Y. Y. Fan et al.

Features

The American Welder

Welding Research Supplement

32

93

43

March 2012 Volume 91 Number 3 AWS Web site www.aws.org

On the cover: A Hydrex senior diver/welder/technician welds a longitudinal stiffener on the side of the Eleftheria K in October 2011 as part of a major repair after the ship had grounded off the Suez Canal. (Photo copyright 2011, Hydrex.)

91 How to Pick the Right-Sized Welding Cable A formula is given to calculate a safe size welding cable,depending on the current used and distance from the powersource

A. F. Manz

93 Welded Benches for Fun and Fund-RaisingWhimsical garden benches were designed and fabricated tohelp raise funds for a project in GuatemalaH. Woodward


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The Eleftheria K (Fig. 1), a Capesize-class bulk carrier, ran aground at themouth of the Suez Canal in July2011. European Navigation, Inc., Piraeus,Greece, operates the ship, which was builtin Japan in 1985. The Eleftheria K is 297m long overall, 50 m in the beam, 214,263metric tons DWT (dry weight), with a26.7-m depth, 19.8-m draught, and a dis-placement of 240,311 tons.

The Damage

When she ran aground, the Eleftheria K had on board a full cargo of iron oreconcentrate, totaling 212,297.75 metrictons, which had been loaded at the portsof Odessa and Yushny in the Ukraine fordischarging at Rizhao and Qingdao,China. The starboard bilge strake wasgrounded at the level of double-bottom

ballast tanks (DBBTs) 1, 2, and 3. Thedamage was extensive, covering about 85m along the hull. The grounding causedsevere indentation of the bilge strake,opening seven holes and cracks along thedamaged area resulting in the flooding of ballast tanks 1, 2, and 3 Fig. 2.

A local diving company in Egypt car-ried out temporary repairs using doublerplates and putty from the outside and ce-ment boxes on the inside Fig. 3. Theship then resumed its voyage to China.However, one week after sailing fromSuez, the ballast tanks flooded again anda vertical crack developed on the star-board vertical side shell plating, on the aftpart of the area damaged by the ground-ing and just forward of the bulkhead be-tween DBBTs 2 and 3, and cargo holds 3and 4 Fig. 4.

The approximately 1300-mm-long

crack had an average uneven gap of 100200 mm. Had it propagated upward,the crack would have caused cargo holds3 and 4 to flood, which could have beencatastrophic for the vessel and her cargo.

The most difficult part of the underwater repairs was covering this crack/frac-ture for it to become watertight while atthe same time maintaining local and lon-gitudinal strength to a level higher thanthe minimum required by the rules.

Underwater repairs and reinforce-ments had to be carried out at a depth of approximately 19 m with the ballast tankflooded, meaning equal pressure from in-side and outside. Repair procedures and

welding quality had to be at maximum inorder to hold firm while deballasting theballast tank so the shell plate could cope

with the resulting hydrostatic pressurefrom the outside. To effect these repairs,

A damaged freighter needed repairs tostop a leak, prevent buckling, and keep

cracks from spreading so the ship couldsail to where she could unload

([email protected]) is withGroup Communications,Hydrex, Clearwater, Fla.

Undertaking a ComplexUnderwater Repair

BY DAVID PHILLIPS

Fig. 1 The Eleftheria Kat sea.

MARCH 201232


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the ship had to be diverted to an anchor-age at Fujairah, United Arab Emirates.

Inspection

S. Georgiou, technical manager of Eu-ropean Navigation, Inc., called in Hydrex,an international underwater repair andmaintenance company based in Antwerp,Belgium. The Hydrex inspection revealeda new vertical crack directly on the bulk-head between ballast tanks 2 and 3.

Georgiou said he decided to call in Hy-drex for the repairs because due to theextent and the severity of the damage, the

job was considered very diff icul t; there-fore, we decided a specialized companysuch as Hydrex, with a successful record,

well organized, safety oriented, and expe-rienced in underwater welding jobs,should be arranged. Furthermore, anyother option to discharge her cargo ashoreand/or transfer the cargo to another ship

was impossible due to the ships size, herdeep draft, quantity of cargo on board, noavailability of suitable port/berth facilitiesfor a vessel of that size in the area, and noavailability of shore floating cranes.

Toon Joos, an experienced seniordiver/welder/technician with Hydrex, flewto Dubai to conduct a detailed inspectionat Fujairah 20 miles off the coast. His re-port and some of the photos from that in-spection follow.

The damage starts approximately onframe number 315 and runs all the way toframe number 227, a total length of ap-proximately 100 m with a height on the

vertical side of approximately 6 m and a width under the flat bottom of approxi-mately 3 m. All the plating is pushed in-side heavily with several cracks that havebeen repaired by other diving companiesby means of doublers and epoxy putty. Un-fortunately, there are still leaks. We cantdetermine the locations due to the previ-

Fig. 2 The ship at anchor near Fujairah, UAE. The ship has a severe list to starboard due to the leaks and flooding of theballast tanks.

Fig. 3 (Top) The buckled hull and the previous attempt at repairs.Fig. 4 (Bottom) Close-up showing the severity of the long, vertical crack discovered in the hull.

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Fig. 5 Sketches of the damage and repair proposal: A Transverse view of the side shell vertical fracture; B repair proposal for the vertical fracture.

Fig. 6 Exterior view of the side shell repair proposal for the vertical fracture.

A

B

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ous repairs and because the tanks (num-bers 1, 2, and 3) are flooded. Betweentanks 2 and 3, I can see there is a crack1300 10 mm just in front of the bulk-head. There is a repair done by (local com-pany), but the shell plating is pushed in-side due to the water pressure when thetank was pumped out.

Planning the Repair

Part of Jooss report was a proposal forrepair of the damage. The idea was to makesufficient repairs for the vessel to sail toChina to unload her freight. Then she couldbe drydocked and permanent repairs made.The main problem was to sufficiently rein-force the 1.3-m vertical crack to prevent thetorsion of the ship while under way fromexpanding it and breaking the ship, and tomake the hull watertight so that the ballasttanks could be pumped out. The first stepof the proposal was to involve a naval ar-chitect so that the various drawings and cal-

culations could be done and approved.

The Naval Architect

Hydrex had recently worked success-fully with Michalis Chourdakis of C. N.Zachopolous & Associates Ltd., marinesurveyors and consultant engineers, Pi-raeus, Greece. The company recom-mended his services to Georgiou, who

was in charge of the repair operation forEuropean Navigation. Chourdakis isalso a technical consultant with TsavlirisSalvage Co., one of the worlds leadingsalvors. In this case, no salvage opera-tion was required so Tsavliris was not in-

volved, but Chourdaki s expla ined tha this work with Tsavliris has given him agreat deal of experience with major re-pairs of this nature.

Chourdakis and his colleague, P.Koutsourakis, a surveyor and specialistin 3D drawings and presentations, stud-ied the results of the Hydrex inspectionand the proposed repairs and worked outthe engineering details. They came up

with a new descript ion of the damage, a

plan for repairs, calculated the variousstrengths and thicknesses required, andproduced a set of drawings.

Grounding Damage

Following is the new damage descrip-tion and temporary repairs proposal.

The damage description is based on in-formation received from the Hydrex diver

on board at Fujairah on May 9, 2011.The report stated in part: On the sideshell plate starboard side and in the areaof the double-bottom ballast tank No. 2starboard found a vertical crack of ap-proximate dimensions 1300 10 mm lo-cated between frames No. 228 and 229 andon the first plate after the bilge plate. Dou-ble-bottom ballast tank No. 2 starboard isflooded Fig. 5.

Repairs Proposal

The purpose of the repairs was to ac-

complish the following:

Fig. 7 Sketches of the sequence(left to right) for fitting the repair.

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Stop the crack (avoid propagation). Reinforce the damaged area. Reinstate water tightness of double-

bottom ballast tank No. 2. Reinstate the continuity of the dou-

ble-bottom side longitudinals. Reinforce the cracked side shell plate

to avoid movement.Following is the repair plan:

To stop the crack and avoid propaga-tion, drill adequate crack-arrest holeson the shell plate at both ends of thecrack Fig. 6.

To reinforce the damaged area, fit fourangle bars and weld them externally onthe shell plate in line with the existingdouble-bottom tanks side longitudi-nals covering two web frame spaces.

Extend the stiffening longitudinallyfrom frame 225 to frame 231.

Fit same-size angle bars and weld them ver tically and in l ine with f rames 228

and 229. These would be extended oneside longitudinal up and down from thecracks ends Fig. 6.

Form the web of the angle bars to ex-actly fit the hulls actual shape.

Three-dimensional fitting sketchesshow how the repair was planned to goforward Fig. 7.

Hydrex confirmed that the plan couldbe executed, and European Navigation ac-cepted the proposals.

All calculations for the local and lon-gitudinal strength of the vessel were sub-mitted and approved by the vessels clas-sification society, Nippon Kaiji Kyokai(Class NK), and H&M Underwriterssurveyors. While the work was beingconducted, a Class NK surveyor was onsite to verify the repairs were carried outaccording to the approved drawings.

Chourdakis noted that for the jobto be successful, high-quality welding

and precise premeasurements wererequired.

Making the Repairs

Hydrex flew two experienced divers/ technicians, Cedric Wyckmans and PhilipMartens, from Antwerp to Dubai to makepreparations for the job, including secur-ing a suitable workboat and other neces-sary equipment. A week later, Joos flewin with a team of four additional divers/

welders/technicians. Work began and con-tinued intensively, day and night, for thenext 5 weeks.

The first step was to take measure-ments for the frame that would be fabri-cated and then welded in place over thelarge vertical crack. The frame would formthe structure of the cofferdam that wouldbe used to make the crack watertight and

would also be used as a frame of reference

Fig. 8 (Top) Construction of the initial frame on the deck of the freighter.

Fig. 9 (Bottom left) The distorted shape of the hull was carefully measured

in relation to the frame, withmeasurements taken every 5 cm, so the

plates that would become the structure of the box could be accurately cut to fit.

Fig. 10 (Bottom right) The plates werelowered down the side of the ship so they could be fitted accurately to the damaged hull before being welded into a watertight

box on deck.

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so that accurate measurements could thenbe made and plates cut and welded inplace. Hydrex welders working with sub-

contractors on the deck of the Eleftheria K constructed the frame Fig. 8.With the frame in place, measurements

could then be taken so that the sides of the cofferdam could be cut to the shapeof the badly buckled hull and then fitted Fig. 9. Joos explained, A good fittingmakes it much easier to weld. Under the

water, a gap of 1 cm is a lot harder to weldthan a gap of 3 mm. If you go over 1 or 1.2cm, then you have to build up. So about 1cm is the limit. Some welders can handlea 1 cm gap. A good fit makes it much eas-ier. If you have a zero gap, it saves hours

and hours of welding time. With the shipout of service until the repairs could becompleted, the old adage, time ismoney, took on a whole new meaning.

The plates were cut on deck, then low-ered and tacked to the hull so they couldbe adjusted to ensure a close fit beforebeing welded to the box Fig. 10.

After the plates were f itted, the 300 60 cm box was constructed on deck Fig. 11. This was done because surface

welding is somewhat faster than underwater welding.

The finished box was then lowered into

the water and welded to the frame and thehull, inside and out, three passes through-

out Fig. 12.Once the box was in place, the stiffen-

ers were ready to be welded onto the hull

extending fore and aft from the crackedhull area. The stiffeners were fabricatedon deck, then lowered into position andtack welded in place. They were then strip

welded with a 15-cm strip every 15 cm, topand bottom of the stiffeners Fig. 13.

The next step was to close the coffer-dam by welding a plate on top of the box that had already been welded to the hulland the frame. When the cofferdam wassealed, the crack was no longer open tothe sea Fig. 14.

Joos recalled the problems encoun-tered when ballast tanks 1, 2, and 3 were

deballasted Fig. 15. When we startedpumping, unfortunately some cracks

broke. Nobody knew what was inside how many longitudinals were still attachedon the inside so we put additional stiff-

eners and then tried to pump again. Again, we had a few minor cracks. Because thedepth of the vessel was 24 meters on thebottom, there was a huge amount of pres-sure forcing inward. The full structureneeded to resist the pressure. We had afew cracks again so we decided to stop andput in some additional stiffeners in morelayers to get more strength on the welds.The third time we started deballastingeverything went okay. There was no fur-ther leak.

Georgiou added, Furthermore, dur-ing the course of repairs due to failure

of the reinforcements the original re-pair plan had to be reviewed twice and

Fig. 11 (Left) The 300 60 cm box fabricated on deck prior to being lowered into the water and welded to the hull.

Fig. 12 (Right) Close-up showing thebox in position over the crack.

Fig. 13 Strip welding the longitudinal stiffeners in place on the shell plate.


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extra stiffeners had to be fitted. Thisproved the degree of difficulty of the job,according to Georgiou.

Finally, just 27 days after work began,the repair was finished with all stiffenersand brackets in place and welded. Epoxy

was applied to prevent the welds fromrusting Fig. 16.

Another team worked on the insideafter the crack was made watertight andthe ballast tanks could be pumped out. It

was with this repair fully completed withclassification society approval that theship was able to sail.

External welding totaled approxi-mately 500 m, an incredible amount of

welding for the given timeframe, par-ticularly when one considers that mostof it was underwater and at consider-able depth. Shielded metal arc welding

was used throughout. Two welding ma-chines worked constantly, and there wasa third on standby as a backup. Theequipment is basically the same as isused above water except that a differ-ent electrode, suitable for underwateruse, is employed.

The underwater external repair was

carried out by seven Hydrex welders work-ing in shifts. The diving routine consistedof two hours under the water followed bya 21-min decompression stop at 3 m andthen a 4-h interval before diving again inthe afternoon, following the same routine.The divers dove once or twice daily fol-lowing the same routine, with two diversin the water at the same time. All thedivers used nitrox, a 40% oxygen/60% ni-trogen mixture.

At the beginning, the divers worked ata depth of 20 to 21 m. When the ballasttanks were emptied and the ship came up

Fig. 14 Closing the cofferdamover the crack.

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straight, recovering from its list, they were working at 17 m.

Georgiou, who chose the repair com-pany and the naval architects, was verysatisfied with the work and the results.We had very good cooperation duringthe entire period of repairs, he said of the teamwork between European Naviga-tion, the naval architect, and Hydrex. Therepair was successful, allowing the vesselto sail to China; therefore, the quality of the job was good. The job completed inabout 27 days, which was very close toquoted time (24 days), but it should beconsidered that additional reinforcementhad to be carried out, therefore the speed

was also satisfactory.

Conclusion

The purpose of this repair to the Eleft- heria K was to stop the leak, prevent buck-ling, and stop the cracks from spreadingso the ship could sail to where she coulddischarge her full load and then go to dry-dock for permanent hull repair. The re-pair was warranted because although the

ship is 27 years old, she has several yearsof service life ahead.

The vessel arrived at its port of des-tination for discharging doing good speeddespite encountering heavy weather and

without any damage to the repairs car-ried out or any other damage, Chour-dakis said.

Georgiou said, Upon completion of underwater repairs, some additional re-pairs/reinforcements carried out insidethe ballast tanks (according to the requestof naval architect) and the vessel was in-spected by Class. Everything was foundokay and she resumed her voyage to Chinato discharge her cargo. The ship arrived

in China after about 30 days voyage, with-out any problem or water ingress in theballast tanks during the voyage, and dis-charged/delivered all her cargo safely, atthe ports of Rizhao and Qingdao. Theprovisional repairs carried out by Hydrex at Khorfakkan anchorage enabled the ves-sel to perform the voyage to her destina-tion safely.

The repairs to the Eleftheria K can beconsidered a major accomplishment in thefield of underwater ship repair and a tes-timony to the skill and teamwork of theship operator, the naval architect, and thedivers/technicians who carried it off suc-cessfully.N

Fig. 15 A Additional reinforcement was added to the repairs to ensure the welds would hold up

when the ballast tanks were emptied; B a close-up of the reinforcement.

Fig. 16 The finished repair. Thewelds were protected with epoxy to

prevent corrosion.

A B

Reprinted with permission from WELDING JOURNAL, March 2012. On the Web at www.aws.org. Permission to reprint in Hydrex Newletter #186

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