Building contemporary, state of the art fleet tanker for Pakistan Navy

Karachi Shipyard & Engineering Works (KS&EW) has build the state of the art, IMO/MARPOL compliant double hull 17000 tonnes displacement Fleet Tanker for Pakistan Navy. The design of PN Fleet Tanker (PNFT) is based on contemporary trends and is according to Bureau Veritas Rules for the Classification of Naval Ships (3rd Party Classification Society). Double hull design will provide PNFT with unrestricted entry into any port of the world.

Primary roles of PNFT is to provide logistics support to PN units at sea in term of dry and liquid cargo (day-night capability), conduct ASW/ASuW operations through embarked organic helicopter, and provide limited medical support to PN units at high seas. PNFT also has capability for defence against Chemical, Biological, Radiological and Nuclear (CBRN) threats. Endurance range of PNFT is +10000 NM at 15 Knots cruising speed, with 3 months naval store and spares capacity. PNFT is around 160 m long, with a beam of 22 m. A tri-party contract, between MoDP, KS&EW, and STM of Turkey for construction PNFT was signed on 22 Jan 13. STM - Turkey has provided Design and KoM for construction of thismega project.

A unique feature of this project is that it involved minimum technical assistance. Total project time including design, construction, and trials was 48 months. As per the provisions of the contract, design and construction was to be executed concurrently, therefore, timely delivery of design plus KoM and subsequent production planning was the biggest challenge in this project.

Steel Cutting & Block Fabrication: Construction of PNFT commence with steel cutting ceremony conducted on 27 Nov 2013. In terms of steel weight, over 6000 tons of steel was cut to fabricate 250 hull blocks of PNFT and other associated outfitting items.

In the past KS&EW has not undertaken cutting of such huge quantity of steel and fabrication of hull blocks for any other singular ship building project. For comparison, steel cut for PNFT is around 6 times that of the steel that was cut for F-22P project i.e. for PNS ASLAT, the 4th state of the art F-22P frigate recently built by KS&EW. In terms of blocks, PNFT has 3 times more hull blocks compared to F 22P.

To meet project time lines and avoid conflict with other ongoing and prospective projects, KS&EW installed another NC Plasma Cutting Machine so that steel cutting for PNFT may continue unhindered on KS&EW’s first NC Plasma Cutting Machine. Block Fabrication Areas were upgraded with modernization of Gantry Cranes and for weight control additional weighing machine was acquired. Furthermore, due extensive and concurrent requirement of welding in all domains of production works, additional welding machines were also procured for this project. Large number of welders were also Class qualified for all welding works (block fabrication, block assembly/erection on berth, piping, outfitting, and electrical works) of PNFT.

Steel cutting and block fabrication of 250 hull blocks was completed in 27 months time.Paint Methodology: Another unique feature of this project is that it was painted under the Class complying IMO/PSPC Regulations MSC 215(82).

This was the first time that a ship under construction at KS&EW was painted under the Class. Under these regulations special dressing of all structures and associated members under ISO 8501-3:2001 (MSC 82/24) was undertaken prior application of paint under strict control of paint manufacturer’s NACE II qualified inspector. Furthermore, all WBTs were painted under Class Notation CPS(WBT). For undertaking and managing this painting regime, NACE I and II qualifications form abroad were duly acquired by KS&EW personnel.

Furthermore, due large number of blocks to be painted, it was envisioned at the beginning that this activity will be a bottle neck for the project. KS&EW therefore installed an additional grit blasting chamber through indigenous resources at considerably reduced cost. The facility provided valuable service not only for this project but for other ongoing shipbuilding projects.

Block Erection At Berth: Keel laying of PNFT was held on 7 Mar 14, 5 months ahead of the contractual date. Due to crane lifting limit of 40 tonnes, 250 hull blocks were fabricated and then assembled on berth.

Intricate task of assembling the ship on berth was conducted under strict dimensional control of the Class. The assembled structure underwent detailed NDT (X-ray, dye penetration, and ultrasound) as per qualification criteria of the Class. A total of 12 decks were assembled on berth, taking the height of the ship to close to 40 m. To facilitate access of workers into the 12 deck ship, a special elevator was installed on berth.

Most challenging part of hull assembly was erection of two shaft bulb blocks/tunnels, for which special laser alignment measure were undertaken to eliminate occurrence of hull vibrations once ship is put into service. PNFT, by weight and number of blocks, is the largest ship to be assembled by KS&EW to date.

Assembly of 250 hull blocks on berth was completed in 26 months time.

Outfitting Activities: Outfitting of 17000 tonnes PNFT has been equally challenging task. Scope of works under this domain includes laying of over 200,000 m cables, fabrication and installation of over 5000 foundations, fabrication and installation of over 40,000 m pipes, painting and insulation of over 500 compartments and tanks, etc. The two RAS masts were also fabricated and installed by KS&EW under Class supervision. Over 300 major equipment were embarked onboard as well.

Most critical outfitting activity was embarkation of 62 tonnes engines onboard for which a 400 tonnes crawler crane was hired from local market. The engines were carefully lowered into the belly of the ship through a well coordinated effort.

Quality Control Regime: PNFT was built under a 6 layer QC regime which includes self checks by workshops, checks by shipyard QC Department, checks by PN inspection teams, Class checks by BV, and paint manufactures checks NACE II inspector. Total 4000 checks/ inspections have been conducted, with first time qualifying percentage standing at around 80%.

Sea Trials: After launching, the setting to work and commissioning of systems installed onboard was another huge challenge. To comply with contractual performance parameters, the ship was to undergo Harbour Acceptance trials of 65 x systems. In addition, more rigorous performance trails were to be performed during sea trials. A total 46 x systems were thoroughly trialed and tested during several sea trips to ensure optimum performance of PNFT as a support platform.

The trial period span to over a year, whereby the ship successfully completed all the Harbour and Sea trials to the entire satisfaction of end user duly complying all contractual requirements.

Conclusion: KS&EW is proud to complete the construction of this largest warship to be built in country to date with earnest zeal and vigour. For this KS&EW is grateful to PN for reposing confidence in KS&EW and awarding this prestigious mega project to KS&EW.

Designed and built on contemporary trends, PNFT is a smart solution for medium size navies of the world and once she enters service in 2018, she will be the first of its kind IMO/MARPOL/PSPC compliant fleet tanker in the world, to proudly flying Pakistani flag to all corners of the globe.

Cdre (r) Saleem Iqbal SI(M) is General Manager (Shipbuilding)