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In this very promising scenario, Projemar is celebrating its 40years of services for the Brazilian offshore and shipbuildingindustries with two innovative conceptual designs developed to

be genuine Brazilian shipbuilding industry answer to Petrobras’upcoming demand, with the history of Projemar as the back-ground that supports this initiative.

Projemar was founded in 1969 as a subsidiary of the formerEmaq shipyard and at that time the main purposes of the companywere the development of shipyard’s ship designs and to becomethe shipyard technological base and so it was that in 1976 Projemarproduced the first mathematical fairing ever in Brazil using a in-house developed software and after that, due to its high develop-ment in the CAD/CAM field, Emaq shipyard and Projemar wereawarded in 1980 with the prize “Liceu de Tecnologia”, the mostimportant technological award in Brazil at that time.

The company took its current form with a management buyout in1995 and started a migration into the offshore design area as theBrazilian shipbuilding industry was being shut down, but theinnovative spirit of the first days remained the same. Today Proje-mar is the most active design company in the offshore oil and gasindustry in Brazil with fourteen FPSO designs and where thecompany took part in several important achievements like:• The first internal turret moored unit – Petrobras P-34 installed at

Barracuda Field in 1997• The first taut-leg mooring system using polyester ropes for a

floating production unit- Petrobras P-19 – installed at MarlinField in 1997;

• The largest to that time floating production unit – Petrobras P-40– installed at Marlin Sul Field in 2001;

The current scenario for Petrobras new developments indicates a verystrong demand for new ship-shaped offshore units to be constructed inBrazil. Eight FPSO hulls are programmed for the new Petrobras shipyard inthe south of Brazil and a total of twenty eight new drilling rigs, includingaround fourteen drillships, are expected for the near future.

Ship shaped offshorehull design

Ricardo Barreto Portellais a Naval Architectgraduated at theFederal University ofRio de Janeiro (UFRJ)has a Master Degree inOcean Engineering atCOPPE – UFRJ (2000)with specialisation in Mooring SystemsDesign and Analysis. He is the Head ofthe Naval Architecture andHydrodynamics Department inPROJEMAR since 1995 where isresponsible for the development ofconceptual and basic design of floatingoffshore structures and ships. Member ofthe Brazilian ABNT CB-50 committee andBrazilian delegate at the ISO TC-67/SC-7for the development of OffshoreStructures for Petroleum and Natural GasIndustries standards.

The Brazilian shipbuilderpoint of view

hull design

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• The biggest dry tow operation in the world, thetransportation of FPU Petrobras P-40 fromSingapore to Rio de Janeiro;

• The first permanent FPSOs moored by aDICAS mooring system – Petrobras P-43 andPetrobras P-48 – installed at Barracuda andCaratinga fields in 2004;

• The largest internal turret installed in a FPSO(first very large turret), with 75 flexible risers –Petrobras P-53 – installed at Marlim Leste fieldin 2008.

Today the Brazilian shipbuilding industry isbooming again, with a considerable number ofnew ships under construction of Brazilian ship-yards. In this new scenario Projemar is responsi-ble for the basic and construction design of themajority of these ships, including:• Four product tankers for PDVSA/PDV Marina• Eight Panamax size tankers for PDVSA• Five full containerships for LOG-IN• Four product carriers for Transpetro

So, this is the company’s background: a lot ofexperience in the Brazilian shipbuilding indus-

try, a lot of experience in the offshore unitsmarket especially related to FPSOs design and astrong vocation to accept challenges, and thedesign of a modern ship shaped offshore unit tobe totally built in Brazil is exactly the type ofchallenge that Projemar would like to have.

In order to be one step ahead in the new verypromising scenario, Projemar has worked on theconceptual design of a new building FPSO hulland on the basic design of a deep water drill-ship, both designed not only to fulfill all Petro-bras requirements but also designed with thepurpose to built by Brazilian shipyards.

Conceptual design of the FPSO hullFor the design of the FPSO Hull, some main

aspects were strongly taken into account:• First of all, the hull’s hydrodynamics should be

improved in order to fulfill the very stronglimits required by Petrobras in terms of motionresponse characteristics;

• Secondly, the arrangement and subdivision ofthe hull shall be able to carry the amount of

The Projemar hull design: main dimensions

Length overall ......................................................................... 330.0 mLength between perpendiculars ......................................... 310.0mBreadth (molded) ................................................................... 56.0 mDepth (molded) ....................................................................... 30.0 mOperational draft ..................................................................... 20.0 mTotal oil storage capacity ............................................... 301,400 m³Available oil for offloading ....................................... 1,680,000 bbl

FPSO Hull concept view

Arrangement of the FPSO Hull

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cargo required by Petrobras, but special atten-tion was taken in order to reduce the hullgirder loads acting on the ship;

• And finally, the ship structure shall be de-signed based on traditional shipbuildingconcepts in order to minimize the steel weightand to reduce the shipyard construction work,having ever in mind that the hull is intendedto be built in Brazil.

In terms of the hull hydrodynamic design,two very important aspects were considered:• The FPSO shall have a limited motion re-

sponse behavior in order to allow the safeoperation of the SLWR (Steel Lazy Wave Riser)

• In addition to this, the hull shall have its totalresistance minimized to improve the mooringsystem design.

In order to achieve the expected motionresponse it shall be considered that limitedmotion means to reduce the first order motionresponse, i.e, to reduce the heave, roll and pitchmotions. Due to the nature of a FPSO hull, theheave motion cannot be modified and in order tominimize the ship motions the hull shall beproperly designed to reduce the roll and pitchmotions.

The FPSO hull motion response was investi-gated using the DnV SESAM / WADAM pro-gram, and when compared with a typical “boxtype” FPSO hull, the Projemar FPSO Hullpresents a better motion behavior that allows forthe use of Steel Lazy Wave Risers.

In terms of arrangement and subdivision, theFPSO Hull first of all follows the Petrobrasspecifications, with a Deck Area that allows morethan 240 m x 50 m of exclusive area for thetopsides modules and a total cargo tanks volumethat allows for more than 1,600,000 bbl availablefor offloading, considering a maximum filling of95%, a minimum filling of 3% and not consider-ing the volume of the slop tanks.

In addition to the Petrobras basic specifica-tions, the following aspects drove the definitionof the FPSO tank arrangement:• Compliance with damage stability regulations• Compliance with MARPOL regulations• Minimize Hull Girder Loads• Minimize sloshing effects in cargo tanks

In terms of its general performance, theFPSO hull shall fit the first class standardrequired by Petrobras for a new building offshoreunit, but it is on the hull structural conceptwhere a truly constructability know-how has tobe shown, in order to avoid a dream of a Brazilianconstruction becaming a nightmare.

First of all, the arrangement of the hullstructure shall be based on traditional shipbuild-ing concepts in order to minimize the steelweight and to reduce the shipyard constructionwork. The FPSO structure design was performedin such a way that the structural arrangementconsiders standard plate sizes from Braziliansteel mills and the longitudinal tanks arrange-ment considers a standardization of the blockssize, reducing dramatically the number of differ-ent steel pieces. It shall also be noted that athree tanks arrangement reduces the reinforce-ments due to sloshing.

Hydrodynamic model ofthe FPSO Hull

FPSO Hull structure concept

hull design

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The vessel’s main dimensions also allow forthe simultaneous construction of two FPSO hullsin the new Petrobras dry-dock of Rio GrandeShipyard. The Projemar hull design has thefollowing main dimensions:Length overall ........................................... 330.0 mLength between perpendiculars .............. 310.0mBreadth (molded) ....................................... 56.0 mDepth (molded) .......................................... 30.0 mOperational draft ........................................ 20.0 mTotal oil storage capacity .................... 301,400 m³Available oil for offloading ............ 1,680,000 bbl

Conceptual design of the drillshipDifferently from the FPSO hull design that is

a Projemar only initiative, the Drillship design isthe result of the joint efforts of Projemar and theDutch company Huisman. This ship is a novelproject, designed to be built in Brazil, for a rigthat is capable to conduct sub-sea BOP drillingoperations in water depths up to 10,000 ft(3050m) and surface BOP drilling operations inwater depths up to 15,000 ft (4570m) with a totaldrilling depth bellow the drill floor of 40,000ft

(12190m). The concep-tual design of thisinnovative drillshipwas presented in T&BPetroleum Magazinelast year, causing avery good impression.

Even being a bitmore compact than itscompeting designs, thevessel offers a largedeck area due to theadvanced drillingequipment conceptdeveloped by Huis-man, specially the

Dual Multi Purpose Tower (DMPT), which isbased on the use of a vertical box structureinstead of the lattice structure of more conven-tional derricks. The box structure provides boththe main load-carrying element and an en-closed environment for the mounting of allmajor equipment, like draw works, compensa-tors, electrical cabinets, drillers cabin etc. thussaving space on the vessel.

The drillship hull design was developed byand is completely integrated with the Huismanequipment. Constructability, focusing the con-struction and integration in existing Brazilianshipyards were a priority, where the key featureis the substructure and Multi Purpose Towerdelivered as one unit by Huisman, allowing theassembly by single lift operations, which simpli-fies the vessel design, reduces the number of theinterfaces and the testing of drilling equipment.Like the design of the FPSO hull, the drillshipdesign considers that the arrangement of thehull structure shall be based on traditionalshipbuilding concepts in order to minimize thesteel weight and to reduce the shipyard con-struction work.

In terms of the vessel operational behaviour,Projemar conducted the stability analysis, mo-tions response and dynamic positioning capacityin order to assure that the vessel complies withall Petrobras expectations for a rig intended towork on the deep waters of the pre-salt area.With excellent motion response characteristicsand a very flexible DP system the vessel is ableto achieve 99.9% of workability for drillingoperations considering the offshore Brazilenvironmental conditions.

Drillship concept view

ship shaped offshore hulls design – the brazilian shipbuilder point of view