hydrex magazine 283 magazine 283 · can be carried out in port or while the vessel is stationary at...

M a g a z i n e Number 283

Seachest insert repair on tanker in Rotterdam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4High quality in-water shiprepair and fuel saving services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Fast propeller repair in Ghent avoids costly drydocking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Hydrex receives grade A wet welding certificate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Hydrex magazine 283_Magazine 283 16/07/20 12:01

2

In-water bow thruster repairs

The Hydrex lightweight flexiblemobdocks are designed to be

easily transported around theworld and are used to close off thethruster tunnel on both sides,allowing divers to perform re-pairs and other operations in adry environment around the bowthruster unit.

This technique enables them to reinstall the propeller blades of anoverhauled thruster inside thethruster tunnel after the unit hasbeen secured or replace the bladesor seals and perform repair work ona specific part without removing theunit.

Since the development of this flexi-ble mobdock technique, numerous

thruster repairs have been carriedout by Hydrex diver/techniciansaround the world.

There is no need to send the vessel to drydock as all operationscan be carried out in port or whilethe vessel is stationary at sea.Normal commercial activities cantherefore continue without disrup-tion.

Phone: + 32 3 213 5300 (24/7)Fax: + 32 3 213 5321 [email protected]

www.hydrex.be


To receive a free copy, e-mail to:[email protected]

In this magazine we write aboutseveral on-site operations car-

ried out by Hydrex diver/techni-cians. These operations were per-formed with one purpose in mind:to keep the customer’s vessel outof drydock and allow him to keephis ship on schedule.

Providing a service that is both ver-satile and effective, Hydrex has builta reputation as the world’s leadingunderwater repair and replacementspecialists. With an ever-expandingworldwide network of offices andsupport bases, we can provide fastservice at reasonable costs.

If you have a problem with your shipof which you are not sure that it can

be solved afloat, you are very wel-come to give us a call. We will evaluate the problem and can let you know whether an underwatersolution is possible. Many solutionsare available without the need fordrydocking.

We can assist you with routinemaintenance operations as well ascomplex repairs. Very simply put:We fix ships.

Hydrex founderBoud Van [email protected]

Editorial Table of contents

ISO 9001 certifiedUnderwater services and technology approved by:

3

High quality in-water shiprepairand fuel saving services 8-9

Fast propeller repair in Ghentavoids costly drydocking 10-13

Hydrex recives grade A wet weldingcertifcate 14

Seachest insert repair on tanker inRotterdam 4-7


Atanker suffered leakage inthe starboard side seachest of

its engine room. We were asked bythe owner to provide an on-sitesolution. For this reason we sent ateam to the ship’s location inRotterdam.

We have our own workboats sta-tioned in Rotterdam ready for imme-diate deployment throughout theport. After the workboat arrived nextto the tanker, the team leader wenton board and met with the captainand chief engineer.

The required on-board safety pro-cedures were performed and diversstarted sealing off all 10 starboardside seachest grids using prefa-bricated steel plates. These weresecured with the proper technique.

On request of the class surveyor, anNDT specialist was arranged to takethickness measurements of the star-board seachest within the engineroom. These measurements showed

that the damage inside the seachestwas wider spread than expected.

Working closely togetherwith all parties involved

With the result of this inspection, a complete repair plan was devisedin cooperation between our team-leader, the ship’s crew and the clas-sification society.

While we finished the blanking ofthe grids, all preparations weremade for the repair work in the en-gine room. This part of the operationwould consist of the installation oftwo inserts in the seachest plating.

The blanking work was finalizedsoon after. The affected seachestcould then be emptied of water andopened. The ship’s crew removedall objects, including the water cool-ers and piping work, from inside theseachest.

Seachest insert repair on tanker in Rotterdam

Preparing blanks for installation.

Hydrex team on its way to tanker in Rotterdam.

4


When the installation was complete,a successful MPI test was carried outby an independent surveyor. As aresult, the class representative gavehis green light for the repair.

The ship’s crew could then re-installeverything in the seachest. Our teamflooded the seachest and final testswere performed to make sure every-thing was watertight. The operationthen ended with the removal of theblanks by our divers.

Conclusion

This operation is a good illustrationof the many benefits we can offershipowners.Certified welders for high

quality repairs

The affected seachest plating wasthen cut away. Our team also tookmeasurements of the port side sea-chest grids and openings to save time

in case a similar repair would berequired on that side in the future.

Our diver/welders worked in shiftsto fit and weld the two insert plates.This was done with class approvedfull penetration weld.

Box cooler being removed from sea chest.

5

Workboat next to tanker during operation.


Positioning one of the new inserts.

6

On the rare occasions where thedamage does not allow such a repair,a temporary doubler plate is instal-led over the affected area. Thisallows the owners to keep to theirschedule and have a permanentrepair carried out during the nextscheduled drydock visit.

To offer the fastest possible serviceto customers, Hydrex offices have

fast response centers where anextensive range of state-of-the-arttools and diving support equip-ment is available at all times forthe repair teams to mobilize toyour location.

Hydrex hull repairs save time and moneyHydrex on-site hull repair

services include the renew-al of both small and large areasof damaged hull plating. Theserepairs can be carried out aboveor below water, according to thecircumstances, with tailor-madecofferdams. Normal commer-cial activities can therefore con-tinue without disruption. Theseoperations follow the Hydrexprocedure for welding cracks inthe vessel's shell plating andthey are approved by all majorclassification societies.

Hydrex diver/technician teamscarry out these on-site hull repairsall over the world. In most casesthe damaged area can be replacedwith a permanent insert and nocondition of class is imposed.


Like all projects we undertake, wetook on, organized and executed theentire job, start to finish. Throughoutthe operation we were in close com-munication with the customer, theclassification society and any otherparty involved. We also provided allthe equipment and materials neededfor the repair. This relieved thecustomer of the hassle of coordina-tion, planning and supervision.

Our offices in Antwerp andRotterdam have workboats availablefor immediate deployment. Thesecan be used for a wide range of operations in Belgium and theNetherlands. This allowed for a fastmobilization to the tanker’s location.

Our team worked in shifts 24/7 tofurther shorten the timeframe need-ed for the repair. This was done tomake sure that any loss of time wasbrought down to the absolute mini-mum.

The owner could continue his vesselon its schedule free of oil leaks andwithout a costly and time-consu-ming trip to drydock.

NDT testing of the welds.

Hydrex diver getting ready for underwater operation inRotterdam.

Securing the new inserts with full penetration weld.

New inserts seen from inside the sea chest.

7

KEEPING SHIPS IN BUSINESS


Permanent insert repairsSpecialist class approved insertrepair work carried out on a permanent basis. Providing a real alternative to drydock.

Emergency repairsFast response emergencyrepairs worldwide.

Inwater video inspectionsProfessional video surveysprovide a reality of the problemand enable owners andclassification surveyors todirectly diagnose any problems.

Echo sounderinspectionand replacement

Hull cleaning onsuitable coatings

Speed logChecks for damage,marine fouling and replacement.

Bilge keelCheck and repairbroken welds, renewalof sacrificial anodes.

Sea vchestIn-wacleanintakeinstalchestcoole

Bow thruster and propellersPermanent on-site repair, maintenance and replacement with the award winning flexible mobdock technique.

High quality in-water ship re pa

8


wals.

Sea valves, sea chests and gratingsIn-water inspection, cleaning and repair of intakes and valves,installation of new sea chests, condensers and coolers afloat.

Stern tube seal replacementPermanent inwater stern tube seal replacements and repairs with the unique Hydrex flexiblemobdock technique.

Propeller operationsPropeller cleaning withspecial tools, on-site bladestraightening and cropping.Permanent repairs to all typesof propellers or installationof propeller cone fins.

Rudder repairsPermanent on-site repairs on all types of rudders with groundbreakingnew technology.

Pintle andbushing repair and replacements

KEEPING SHIPSIN BUSINESS

re pair and fuel saving services

9


In the following example croppingwas the only option as the type ofdamage to the propeller blade didnot allow cold straightening. Incases like this, where there is aneven number of blades an identicalpiece will be cropped from the oppo-site blade to restore the hydrody-namic balance of the propeller. Bydoing so, the best possible efficiencyis obtained.

Single day operation restoresefficiency

Two of the four blades of the bulkerhad lost part of their tip. An on-sitesolution was needed to restore thepropeller’s balance and efficiency.A team was therefore mobilized

Recently we performed a pro-peller blade cropping on a

180-meter bulker berthed inGhent. The tip of two of the fourpropeller blades was severelydamaged and needed to be crop-ped to restore the propeller’s effi-ciency. The trailing edge of theother blades had suffered cracksthat needed to be repaired.

Having developed different proce-dures for different kinds of damage,Hydrex teams are equipped and trained to make the best out of a bent or broken propeller. Ideally, thein-house developed cold straight-ening technique is used. This pro-cedure enables us to straighten damaged blades in-water, allowing commercial operations to continuewithout the need to drydock.

Fast propeller repair in Ghent avoids costly drydocking

Dye inspection of the blade after cropping.

10

Trimmed propeller blade of bulker with damaged tip.


from our headquarters in Antwerp tothe ship’s location in Ghent.

After the equipment arrived at thevessel our men started the operationwith a detailed survey of the propel-ler blades. They used the informa-tion acquired during the inspection

to calculate and determine the cor-rect measurements needed to modifythe propeller blades. The first bladewas then cropped and ground to giveit the correct radius. The opposingblade was modified using the exactsame cutting line, to give the propel-ler back its balance.

11

Permanent in-water rudder

repairs now possible without

drydocking

Hydrex has developed an en-tirely new method enabling

permanent repairs of rudders without drydocking the ship.Permanent repairs were hithertonot possible and ships had todrydock in case a major defectwas found. The newly designedequip ment is light-weight andcan be mobilized very rapidly in our special flight containers.Therefore this new service is nowavailable world-wide.

Major defects on rudders very of-ten cause unscheduled drydockingof ships. The new method designedby our technical department allowsengineers, welders and inspectorsto perform their tasks in dry con-ditions. Class approved permanentrepairs on-site, without moving theship, are now possible and com-mercial operations can continue.Steel repairs and replacements canbe performed and pintle and bush-ing defects can be solved withoutthe loss of time and money asso-ciated with drydocking.

The equipment can be mobilizedwithin hours to any port in theworld and is available for rapidmobilization from the Hydrexheadquarters in Antwerp.

Blades can also be cropped underwater by our diver/technicians if needed.


12

Stern tube seal repairs

Using our flexible mobdockmethod to create a dry under-

water environment, we have car-ried out stern tube seal repairsand replacements underwater forsome years now in cooperationwith OEMs.

This technology brings drydock

conditions to the ship rather thanhaving to take the ship to drydock,saving a considerable amount oftime and money in doing so.

This class accepted method is performed by our diving teamsunder our warranty. It can be usedwhile the ship is carrying out its

usual cargo or other commercialoperations in port.

Visit the special stern tube sealrepair section on our website formore information and examples of the many seal repairs we haveperformed in recent years.

Phone: + 32 3 213 5300 (24/7)Fax: + 32 3 213 5321 [email protected]

www.hydrex.be


When the cropping was complete,small cracks were grinded out of thetrailing edges of the other blades.This was done to make sure that anyremaining loss of efficiency wouldbe minimal.

Conclusion

Over 45 years of experience withpropeller repairs have given us thetools and know-how to offer fastrepair and modification services tovessels around the world. All typesof operations can be carried out fastand efficiently afloat and under-water.

In this case the repair took less than aday. This prevented any unwelcomedelay to the vessel’s schedule.

The edges of the affected blades are polished for maximum efficiency.

If possible, bent blades are restored with our cold straightening machine.

13

If you have received this magazine at the wrong

address or if your company is going to move,

please let us know.

You can contact us at:

[email protected] at

+ 32 3 213 53 00

KEEPING SHIPS IN BUSINESS


This is a major benefit for offshoreunits where high quality standardsneed to be verified before weldingoperations like doubler repairs canbe performed.

We have received the approvalto carry out classification

certified grade A wet welding. To guarantee the required highstandard of these underwaterwelds, NDT tests were performedby ABS surveyors before the cer-tificate was awarded.

The certificate was given to carryout grade A groove welding under-water. Cavitation or corrosion dam-age on rudders, clad welding, ropeguard repairs, mewis duct repairs, …can now be done with permanentwelding.

With a class B weld an inspection ofthe weld is required every threemonths. With class A welding thedeadline for an inspection is muchlonger. This is decided by the at-tending surveyor on a case by casebasis.

Any required inspection will be forthe underlying problem causing thedamage and not for the weldingwork. An internal structural problemcausing damage will not always behandled after the repair and willneed to be followed up. For instance,doubler repairs can never be perma-nent because the doubler is installedover the damaged plating instead ofreplacing it (as is the case with insertrepairs).

With class A underwater weldingonly a note is made stating that theaffected area needs to be looked atduring the next scheduled inspec-tion. This is very important for tank-ers as a clean class certificate isrequested by most charterers.

Even for non-class items such asrope guards the certificate is usefulbecause it shows our customers thatour diver/welders can carry out highquality underwater welding work.

Hydrex receives grade A wet welding certificate

We have received the approval to carry out classification certified grade A wetwelding.

Weld seams of doubler plate installed over damaged hull area.

14


15

Phone: + 32 3 213 5300 (24/7)Fax: + 32 3 213 5321

[email protected]

We discovered an unsophis-ticated but very efficient

technology to enhance propellerblade surfaces. With this methodwe can achieve surface conditionsthat were never seen before. Thiscan only be done underwater.

We have four workboats equippedto deliver this service on a veryshort notice in the Rhine-Scheldtdelta from Antwerp to Rotterdam.

propeller surfaces. Continuous andlarge fuel savings are now possi-ble.

This award-winning surface treat-ment technique justifies havingthe propeller cleaned every time itcalls a port.

Please contact us for more infor-mation, we will gladly discuss thebenefits of this new technologywith you.

When a comparison is made betweenthe surface condition of an averagepropeller, as our divers regularly seeit, and the smoothness that is obtainedwith our cleaning technique, savingsare in the 5-10% range. These resultsare easily achieved. The cost of suchan operation is very attractive and isvery easily gained back in a matter ofdays (or even hours).

Regular maintenance is easy toschedule and results in ultra-smooth

Large fuel savings with new propellersurface treatment technique


www.hydrex.be

Headquarters Hydrex N.V. - AntwerpPhone: + 32 3 213 5300 (24/7)E-mail: [email protected]

Hydrex Spain - AlgecirasPhone: + 34 956 675 049 (24/7)E-mail: [email protected]

Hydrex LLC - Tampa, U.S.A.Phone: + 1 727 443 3900 (24/7)E-mail: [email protected]

Hydrex RotterdamPhone: +31 10 313 25 19 (24/7)E-mail: [email protected]

We fix ships worldwide

This drawing was made in 1979and symbolizes our care and attention for ships.


hydrex magazine 283 magazine 283 · can be carried out in port or while the vessel is stationary at...

Documents