3 polar & abs ice classes greece nov2011.pdf

8/10/2019 3 Polar & ABS Ice Classes Greece NOV2011.pdf

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Harsh Environments Seminars

Greece/Cyprus

1-2 November 2011

IACS Polar Class Rules &

John DolnyEn ineer Harsh Environment Technolo Center

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ABS


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Development of the Polar Class UR & IMOArctic Guidelines

The 1970s and 1980s saw increased activities in the

Arctic re ions

Alaska and Canadian Beaufort Sea

Several Administrations made proposals to IMO to

develop a harmonized system of Ice Class Rules

Consensus was reached at IMO

IMO would develop the

overall framework for the

initiative

SS Manhattan (Esso Arctic Project)

IACS would produce

detailed requirements for

-

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IACS Polar Class: A Brief Background

IACS Unified Requirements Concerning Polar Class

1993-2006

Hull structure (UR-I2) and machinery (UR-I3)

Published as ABS Guide for Vessels Intended for

Polar Waters (2008)

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Since Publication

Increased interest from a variety of stakeholders

OSVs Icebreakers

r s ps

Commodity transport

Tankers

LNG

Bulk carriersCanmar Kigoriak

Naval Ships

Coast Guard

Vasily Dinkov

Research related

Nathaniel B. Palmer (courtesy of NSF)

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Major Parts of IACS Polar Class: UR I2

Hull Areas (I2.2)

.

Shell Plate Requirements (I2.4)

. - .

Transversely-framed

Longitudinally-framed

Structural stability

Corrosion and Abrasion (I2.11)

Materials (I2.12)

Longitudinal Strength (I2.13)

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Major Parts of IACS Polar Class: UR I3

Materials (I3.3)

.

Design (I3.5)

Machiner fastenin loadin

accelerations (I3.6)

Auxiliary systems (I3.7) Sea inlets and cooling water systems

(I3.8)

Ballast tanks I3.9

Ventilation system (I3.10)

e o ar ass u es are t e est ava a e as s or t e es gn

of the next generation of ice-capable ships.

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Items Addressed in Polar Class URbut Specifics Left to Class Requirements

Icebreaker notation

-

Large framing member girders, stringers, web frames

Stem and stern frames

Equivalent dimensions for non-tee stiffeners

Additional inertial force for structures not directly

contacting ice

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Recent Industry Trends

IACS Unified Requirements for Polar Class (Polar

UR is becomin further endorsed b maritime

authorities IMO Guidelines for Ships Operating in Polar Waters

Polar Code expected to become mandatory

References IACS Polar Class UR ABS replaced the ABS General Ice Class notations

with IACS Polar Class notations

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Issues

Many important issues are not addressed in Polar

UR left to class societies to rovide uidance

Where the Polar UR does not have a requirementcomparable to an existing ABS requirement, ABS

requirement has been retained for an optional

Enhanced notation Low ABS General Ice Class (A0-D0) retained as

First-year Ice Class

u e or esse s n en e or av ga on nPolar Waters will be obsolete upon publication of

the new ABS Ice Class Rules

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2012 Ice Rules Reorganization

SVR 6-1-1 SVR 6-1-1

Current SVR* SVR 2012

ABS General Ice Class

A1 A5

A0 D0

IACS UR I1

SVR 6-1-2

IACS UR I2Polar Class

SVR 6-1-2

Baltic Ice Class Rules

SVR 6-1-3

IACS UR I3

ABS Polar Water Guide

IACS Polar Class

- -

Polar Class ENHANCED

SVR 6-1-5

A0-D0, First-year Ice Class

Non-self-propelled Vessels (Barges)

SVR 6-1-6

Baltic Ice Class Rules

* SVR Steel Vessel Rules

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2012 Notations

Polar Class

(6-1-1, 6-1-2,

Polar Class,Enhanced

First-yearIce Class

BalticClass

- - - - - - - -

PC1 PC1, Enhanced

PC2 PC2, Enhanced

,

PC4 PC4, Enhanced

PC5 PC5, Enhanced,

PC7 PC7, Enhanced A0 1A

B0 1B

D0

The shaded columns shaded are eligible for icebreaker class notation

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Technical Areas of Misunderstanding

Non-icebreaking bows

principles

Appendages and azimuthing

thrusters

Courtesy of Helsinki Commission, Ice

Expert Working Group, November 2003

Large structural members

Double-actin desi n conce t

Material grades and classes

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Bulbous Bow for Polar Ships

The Polar Rules design bow ice load formula

considers actual bow eometr

Incorporates a simplification and assumptions only validfor icebreaking bow forms

ABS is currently developing a solution for non-

icebreaking bow forms

(FSICR, ASPPR, ABS GIC)

Nominal ice load with increased

Direct design approach

Derive load formulations based

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on bulbous bow impact scenarios

Courtesy of Transport Canada


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Equivalency

One-to-one equivalency cannot be established among

Ice Class notations

Issues to be considered for comparison Number of ice classes are different

,

Net scantling corrosion and abrasion allowance

Steel renewal

For stiffeners section modulus shear area and steel wei ht

Elastic versus plastic approach

Approximate correspondence between class requirements is

The designs of Polar Class vessels are very limited

Powerin cannot be com ared due to lack of minimum ower

requirement of Polar Class UR

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Azimuthing Thrusters

Stern hull structure

aggressive maneuvering from azimuthing thrusters Area factors for Stern Icebelt and Stern Lower

Thruster loading criteria

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Structural Requirements in the Polar UR

Directly address

Main frames

(stiffeners)Web frames

Shell plating

Ice deck plating

Deck beams and transverse

Bulkhead plating

Intermediate

stringerStringers

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ea rames



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6-1-2 Structural Requirements (UR-I2)

15.7-15.11 Structural Requirements for Web Frames and

Load-carrying Stringers

IACS UR leaves these to the requirements of membersociety

Supplementary development completed by ABS in 2011

Transverse and longitudinally framed arrangements

Required plastic section modulus (plastic moment)

Derived from a simplified solution of analysis of plastic

mechanisms

Lightening holes and cut-outs requires further development

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6-1-3 Machinery Requirements (UR-I3)

Extensive IACS driven UR-I3 developments since

2008

Fatigue design principles for propeller design Blade flange, bolts, propeller hub and CP mechanism

cr er a

Propulsion line components

Propeller fitting, shaft diameters and connections

Gear transmissions, clutches, elastic couplings,

crankshafts, bearings and seals

Rudder actuator holding torque and relief arrangements

Develo ments included in 2012 ABS SVR

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6-1-4 Requirements for Enhanced Polar Class

Ice Breaker Notation (optional)

experience Available for PC1-PC6, Enhanced

Increase hull area factors (structural redundancy)

Includes powering recommendation

esse s n en e o pera e

Astern (optional)

Stern section treated as a bow

Adjusted hull area factor table

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Nathaniel B. Palmer (courtesy of NSF)


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Requirements retained from ABS General Ice Class

Main and intermediate frame connections and extentsWeb frame and ice stringer connections

an arrangemen s

Longitudinal framing

Peak frames

Double bottoms

Ice decks

Bulkheads


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Requirements retained from ABS General Ice Class

Machinery arrangements Recommended propulsion

power ng

Maximum thickness of

consolidated level ice Courtesy of Aker Arctic Technology

Total power delivered to propellers

Powering criteria from model test

Bossings

Rudder and steering arrangements

Propeller nozzles

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6-1-5 Requirements for Vessels Intended forNavigation in First-year Ice

Based onABS General Ice Class requirements

, , ,

Includes requirements for non-self-propelled vessels(6-1-5/31)

A

BQ

Stern

Area

Midbody AreaBow

AreaUpper Ice WL

Lower Ice WL

A

D

Upper Ice WL

Lower Ice WL

A

B

Bow Area

A + D

S F

Whicheveris higher

whicheveris higher

FP

FN

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USNS Lewis and Clark (T-AKE-1), Ice Class C0


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6-1-6 Baltic Ice Classes

Relocated from 6-1-2

- ,

as amended 2011 draft includes quite extensive revisions from TraFi*

(former FMA**)

*Finnish Transport Safety Agency, since 2010

** Finnish Maritime Administration

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Summary of 2012 Ice Rule Reorganization

This approach aligns the ABS Ice Class notations

with the antici ated mandator Polar Code

(expected in 2012), which references the IACS PolarIce Classes

Keeping-up with current industry standards

The Enhanced notation and First-year Ice Class Preserve the experience and service record reflected

in the ABS General Ice Class

Without creatin a com etitive disadvanta e a ainst

other class societies Polar Class

Note: IACS requirements are only published in metric units. ABS has

.

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Software Tools

IACS UR Polar Rules came into force in March 2008

Three unit systems

Steel Vessels Rules

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Concluding Remarks

IACS Polar Class UR is a minimum requirement

gaps

supplemental criteria, harmonization will be

important Other guides and tools are

currently available to assist

Polar UR

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www.eagle.org

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3 polar & abs ice classes greece nov2011.pdf

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