LNG CarriersLNG CarriersShip Life ExtensionShip Life Extension

Ed WaryasEd WaryasLloyd’s Register North America, IncLloyd’s Register North America, Inc.

Longevity Study - Outline

Owners Records

Classification Records

Ship inspection

RAM Study

Structural Integrity Analysis

Owner’s Records

Owners records

Classification Records

Shipboard Records

Ship Inspection

Single Ship or Fleet

Voyage

During Refit

Hull Structure

External Hull

Water Ballast Tanks

Thickness Measurements

Paint coatings

Machinery

Redundancy

Main Engine

Boilers

Auxiliaries

Pumps & Piping

ElectricalAlternators

Switchboards

Cabling

Motors

Control & Alarm Systems

Cargo Systems

Containment

Cargo Pumps

Piping

Auxiliaries

RAM Study(Reliability, Availability, Maintainability)

The RAM study The RAM study -- provides information provides information on future fleet performance and on future fleet performance and availabilityavailability

Trade FeasibilityTrade Feasibility

UtilizationUtilization

RAM Study

The TaskThe Task

The MethodThe Method

DataData

Simulation Input Simulation Input -- ValidationValidation

Simulation OutputSimulation Output

ConclusionsConclusions

THE TASKTHE TASK

Assess the capacity of an LNGAssess the capacity of an LNGcarrier/fleet to maintain existing carrier/fleet to maintain existing availability over the 20 year life availability over the 20 year life extension period.extension period.

Identify performance critical Identify performance critical systems. systems.

Availability?Availability?

CLIENTASSESSMENT OFRISK AND COSTACCEPTABLE.

DERIVE PROBABILITYOF LOSS OF CRITICALSYSTEMS, FUNCTION& TRADE TARGETS.

VALIDATION OK

SYSTEM DATA ANDFUNCTIONINFORMATIONCOLLECTION.

ANALYSIS OF RAMDATA FOR CRITICALSYSTEMS ANDFUNCTIONS.

RUN FLEET ENOUGHTIMES OVER PERIODREQUIRED TO GIVECONFIDENCE.

FLEET DATA INPUT

IF OPERATING POLICY IS INADEQUATE,REVIEW MAINTENANCE POLICYTHROUGH APPLICATION OF RELIABILITYCENTERED MAINTENANCE TECHNIQUES.

SYSTEM ANALYSISWITH MARINE TRADEEXPERT INPUT.

IDENTIFICATION OFSHIP, FLEET ANDTRADE CRITICALSYSTEMS.

REVIEW RESULTS WITH CLIENT. DISCUSSVARIATIONS IN CONFIGURATION ANDOPERATING POLICY.

... UNTIL

AGREE DATA ANDPROCESSES FORSYSTEM MODELWITH CLIENT.

THE METHODTHE METHOD

Company records

Supported by LR’s own database

For a five year period typical data indicates:

Dry-dock2.25%

Delays0.64% Availability

97.11%

DATA DATA -- RECORDSRECORDS

DATA - TRADE

LNG cargo lifts from load ports

Regas delivery points

(Analysis of vessel trading routes)

SIMULATION INPUT SIMULATION INPUT --VALIDATION

Trade detailTrade detail

Seasonal weather detailSeasonal weather detail

Ship critical system RAM dataShip critical system RAM data

Ship capacityShip capacity

Operating rulesOperating rules

Ship and fleet speed controlShip and fleet speed control

SIMULATION OUTPUTSIMULATION OUTPUT

The following typical results can be The following typical results can be derived:derived:

Data Analysis FLEET modeling

Delay based NetAvailability

97.1% 96.1%

Typical ConclusionsTypical Conclusions

Trade expansion may be limited.Trade expansion may be limited.

Enhanced maintenance actions and data Enhanced maintenance actions and data recording will improve performance.recording will improve performance.

Fleet utilisation is low Fleet utilisation is low -- RAM RAM performance does not affect the performance does not affect the current trades.current trades.

Structural Integrity Analysis

The main purpose of the Structural Integrity Analysis is to compliment the inspections, which establish the current condition and past record, by calculating the likely future structural performance of key components.

From this, key structural components which may require repair or modification over the extension period can be identified.

Structural Integrity Analysis

The three principal components are:

wave loading

evaluation of hull structure

evaluation of cargo containment system

Wave Loading

Determination of long term wave loading, ship motions and accelerations

for specified trading routes

in full load and ballast conditions

at typical operational speeds

Hull Structure

Investigation consists of two levels:

strength and fatigue of hull girder

finite element modelling to establish detail stresses at critical connection points

Fatigue of hull longitudinalsat typical transverse bulkhead

Hull Structure -finite element analysis

To determine stresses and stress concentrations at typical hull details, e.g.

hopper connections

trunk deck endings

double bottom girder / transverse bulkhead connection

Finite Element Model

Ballast Hogging ConditionInner Hull and Deck Stresses

Stresses at Detail : Hopper Knuckle

Fatigue analysis of cargo tank membranesAnalysis examined, for N. Atlantic -

primary membrane strake end connections

secondary membrane chair washer

pipe tower base support to primary membrane

trihedron connections to primary membrane

Typical Conclusions

Steel hull structure -

Providing maintenance continues, and structural repairs performed, then hull integrity can be assured over proposed total ship life of 40 years.

Cargo tank membrane system -

The membrane system could be expected to perform satisfactorily for the proposed 40 year life.