SVR_Part_6_e-July17.pdf

P a r t 6 : S p e c i a l i z e d I t e m s a n d S y s t e m s

RULES FOR BUILDING AND CLASSING

STEEL VESSELS

PART 6

SPECIALIZED ITEMS AND SYSTEMS

(Updated July 2017 – see next page)

American Bureau of Shipping Incorporated by Act of Legislature of the State of New York 1862

2016 American Bureau of Shipping. All rights reserved.

ABS Plaza 16855 Northchase Drive Houston, TX 77060 USA

Updates

July 2017 consolidation includes:

• May 2017 version plus Notice No. 1

May 2017 consolidation includes:

• January 2017 version plus Corrigenda/Editorials

R u l e C h a n g e N o t i c e ( 2 0 1 7 )

Rule Change Notice (2017) The effective date of each technical change since 1993 is shown in parenthesis at the end of the subsection/paragraph titles within the text of each Part. Unless a particular date and month are shown, the years in parentheses refer to the following effective dates:

(2000) and after 1 January 2000 (and subsequent years) (1996) 9 May 1996 (1999) 12 May 1999 (1995) 15 May 1995 (1998) 13 May 1998 (1994) 9 May 1994 (1997) 19 May 1997 (1993) 11 May 1993

Listing by Effective Dates of Changes from the 2016 Rules

Notice No. 1 (effective on 1 July 2016) to the 2016 Rules, is summarized below.

EFFECTIVE DATE 1 July 2016 – shown as (1 July 2016) (based on the contract date for new construction between builder and Owner)

Part/Para. No. Title/Subject Status/Remarks 6-2-1/7.1.4 Vessels Carrying Cargo in

Refrigerated Containers of Integral Type, À IRCC

To provide a reference to the ABS Guide for Carriage of Integral Refrigerated Containers On Board Ships. (Incorporates Notice No. 1)

6-2-13/5 Integral Refrigerated Cargo Container Carrier

To provide a reference to the ABS Guide for Carriage of Integral Refrigerated Containers On Board Ships. (Incorporates Notice No. 1)

EFFECTIVE DATE 1 January 2017 – shown as (2017) (based on the contract date for construction between builder and Owner)

Part/Para. No. Title/Subject Status/Remarks 6-2-1/5.7 <No Title> To clarify class requirements associated with liquefied gas compressors and associated re-liquefaction systems.

Listing by Effective Dates of Changes from the 2017 Rules

Notice No. 1 (effective on 1 July 2017) to the 2017 Rules is summarized below.

EFFECTIVE DATE 1 July 2017 – shown as (1 July 2017) (based on the contract date for new construction between builder and Owner)

Part/Para. No. Title/Subject Status/Remarks Part 6 Specialized Items and Systems To clarify that the requirements in Part 6 are not optional if the items or systems are to be classed. (Incorporates Notice No. 1)

6-1-1/Table 1 Ice Class Notations To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-1/1.1 Application – Polar Class To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-1/5.3 Upper and Lower Ice Waterlines To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/3.1vii) (New)

<No Title> To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/5.1 General To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017 iii

Part/Para. No. Title/Subject Status/Remarks 6-1-2/5.3 Glancing Impact Load Characteristics To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and

IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/Table 1 Class Factors to be Used in 6-1-2/5.5iii) To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/Table 2 (New)

Class Factors to be Used in 6-1-2/5.5iv) To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/5.5iii) <No Title> To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/5.5iv) (New)

<No Title> To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/5.5.6 (New)

Shape Coefficient To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/5.5.7 (New)

Force To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/5.5.8 (New)

Line Load To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/5.5.9 (New)

Pressure To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/Table 3 Peak Pressure Factors To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/5.13 Hull Area Factors To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/Table 4 Hull Area Factors (AF) for Vessels Intended to Operate Ahead Only

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/Table 5 (New)

Hull Area Factors (AF) for Vessels Intended to Operate Ahead and Astern

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/Table 6 (New)

Hull Area Factors (AF) for Vessels with Additional Notation Ice Breaker and Intended to Operate Ahead Only

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/Table 7 (New)

Hull Area Factors (AF) for Vessels with Additional Notation Ice Breaker and Intended to Operate Ahead and Astern

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/7.3 Shell Plate Thickness to Resist Ice Load

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/9.9 Framing Span To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/9.13 Net Effective Shear Area To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/9.15 Net Effective Plastic Section Modulus To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/11 Framing – Local Frames in Bottom Structures and Transverse Local Frames in Side Structures

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/13 Framing – Longitudinal Local Frames in Side Structures

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/13.1 Plastic Strength To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/13.3 Required Shear Area To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1) iv ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017

Part/Para. No. Title/Subject Status/Remarks 6-1-2/15.3 Application To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and

IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/15.7 (Deleted)

Actual Net Effective Shear Area and Plastic Section Modulus

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/15.9 (Deleted)

Scantling Requirement for Transversely-framed Side Structures

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/15.11 (Deleted)

Scantling Requirement for Large Members of Longitudinally-framed Structures

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/21.3 Corrosion/Abrasion Additions for Shell Plating

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/Table 8 Corrosion/Abrasion Additions for Shell Plating for Vessels Intended to Operate Ahead Only

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/Table 9 (New)

Corrosion/Abrasion Additions for Shell Plating for Vessels Intended to Operate Ahead and Astern

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/23.1 General To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/23.11 (Deleted)

Steel Grades for Inboard Framing Members

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/Table 7 (Deleted)

Steel Grades for Inboard Framing Members Attached to Weather Exposed Plating

To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/25.1 Application To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/Table 12 Longitudinal Strength Criteria To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-2/33 Direct Calculations To align the requirements with IACS UR I1 (Rev. 2 Apr 2016) and IACS UR I2 (Rev. 3 Apr 2016). (Incorporates Notice No. 1)

6-1-4/3 (Deleted)

Ice Breaker Class To align the requirements with the revisions to Sections 6-1-1 and 6-1-2. (Incorporates Notice No. 1)

6-1-4/Table 1 (Deleted)

Hull Area Factors (AF) for Vessels with Ice Breaker Class Notation

To align the requirements with the revisions to Sections 6-1-1 and 6-1-2. (Incorporates Notice No. 1)

6-1-4/5 (Deleted)

Vessels Intended to Operate Astern To align the requirements with the revisions to Sections 6-1-1 and 6-1-2. (Incorporates Notice No. 1)

6-1-4/Table 2 (Deleted)

Hull Area Factors (AF) for Vessels Intended to Operate Astern

To align the requirements with the revisions to Sections 6-1-1 and 6-1-2. (Incorporates Notice No. 1)

6-1-4/3.5.2v) <No Title> To align the requirements with the revisions to Sections 6-1-1 and 6-1-2. (Incorporates Notice No. 1)

6-1-4/5.1 Struts To align the requirements with the revisions to Sections 6-1-1 and 6-1-2. (Incorporates Notice No. 1)

6-1-4/11.3 Deck Plating To align the requirements with the revisions to Sections 6-1-1 and 6-1-2. (Incorporates Notice No. 1)

6-1-4/11.5.3 Scantlings To align the requirements with the revisions to Sections 6-1-1 and 6-1-2. (Incorporates Notice No. 1)

6-1-4/11.7 Decks with Wide Openings To align the requirements with the revisions to Sections 6-1-1 and 6-1-2. (Incorporates Notice No. 1)

6-1-4/13.3 Scantlings To align the requirements with the revisions to Sections 6-1-1 and 6-1-2. (Incorporates Notice No. 1)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017 v

P A R T T a b l e o f C o n t e n t s

Specialized Items and Systems (1 July 2017)

CONTENTS

CHAPTER 1 Strengthening for Navigation in Ice

Section 1 Introduction Section 2 Structural Requirements for Polar Class Vessels Section 3 Machinery Requirements for Polar Class Vessels Section 4 Requirements for Enhanced Polar Class Notation Section 5 Requirements for Vessels Intended for Navigation in

First-year Ice Section 6 Baltic Ice Classes

Appendix 1 – Ice Class Draft Marking Appendix 2 – The Validity of the Powering Requirement in 6-1-6/9.1.2

CHAPTER 2 Vessels Intended to Carry Refrigerated Cargoes

Section 1 General Section 2 Plans and Data to be Submitted Section 3 Hull Construction Section 4 Cargo Handling Equipment Section 5 Refrigerated Cargo Spaces Section 6 Refrigeration Machinery Section 7 Ancillary Systems Section 8 Fire Extinguishing Systems and Equipment Section 9 Electrical Systems Section 10 Instrumentation, Control and Monitoring Section 11 Ammonia Refrigeration System Section 12 Controlled Atmosphere Systems Section 13 Refrigerated Cargo Container Carrier Section 14 Refrigerated Edible Bulk Liquid Tanker Section 15 Refrigerated Fish Carrier Section 16 Testing vi ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017

P A R T C h a p t e r 1 : S t r e n g t h e n i n g f o r N a v i g a t i o n i n I c e

C H A P T E R 1 Strengthening for Navigation in Ice

CONTENTS

SECTION 1 Introduction

1 General

1.1 Application – Polar Class

3 Description of Polar Class

3.1 Selection of Polar Classes

5 Definitions

5.1 Ice Belt

5.3 Upper and Lower Ice Waterlines

5.5 Displacement

5.7 Length

TABLE 1 Ice Class Notations TABLE 2 Polar Class Descriptions

SECTION 2 Structural Requirements for Polar Class Vessels

1 Application 3 Hull Areas

3.1 General

5 Design Ice Loads

5.1 General

5.3 Glancing Impact Load Characteristics

5.5 Bow Area

5.7 Hull Areas Other Than the Bow

5.9 Design Load Patch

5.11 Pressure within the Design Load Patch

5.13 Hull Area Factors

7 Shell Plate Requirements

7.1 Required Minimum Shell Plate Thickness

7.3 Shell Plate Thickness to Resist Ice Load

7.5 Changes in Plating Thickness

9 Framing – General

9.1 General

9.3 Application

9.5 Fixity

9.7 Details

9.9 Framing Span

9.11 Scantlings

9.13 Net Effective Shear Area

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017 1

9.15 Net Effective Plastic Section Modulus

9.17 Oblique Framing

11 Framing – Local Frames in Bottom Structures and Transverse Local Frames in Side Structures

11.1 Plastic Strength

11.3 Required Shear Area

11.5 Required Plastic Section Modulus

11.7 Structural Stability

13 Framing – Longitudinal Local Frames in Side Structures

13.1 Plastic Strength

13.3 Required Shear Area

13.5 Required Plastic Section Modulus

13.7 Structural Stability

15 Framing – Web Frames and Load-carrying Stringers

15.1 General

15.3 Application

15.5 Structural Stability

17 Framing – Structural Stability

17.1 Framing Members

17.3 Web Stiffening

17.5 Web Thickness

17.7 Flange Width and Outstand

19 Plated Structures

19.1 General

19.3 End Fixity

19.5 Stability

21 Corrosion/Abrasion Additions and Steel Renewal

21.1 General

21.3 Corrosion/Abrasion Additions for Shell Plating

21.5 Corrosion/Abrasion Additions for Internal Structures

21.7 Steel Renewal

23 Materials

23.1 General

23.3 Material Classes

23.5 Steel Grades

23.7 Steel Grades for Weather Exposed Plating

23.9 Castings

25 Longitudinal Strength

25.1 Application

25.3 Design Vertical Ice Force at the Bow

25.5 Design Vertical Shear Force

25.7 Design Vertical Ice Bending Moment

25.9 Longitudinal Strength Criteria

27 Stem and Stern Frames 29 Appendages

29.1 General

29.3 Load Definition and Response Criteria

2 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017

31 Local Details

31.1 General

31.3 Cut-outs

33 Direct Calculations

33.1 General

33.3 Load Patch

33.5 Strength Evaluation

33.7 Acceptance Criteria – Linear Analysis Methods

33.9 Acceptance Criteria – Non-linear Analysis Methods

35 Welding

35.1 General

35.3 Continuity of Strength

35.5 Filler Metals

35.7 Hull Steels Other than the ABS Grades

TABLE 1 Class Factors to be Used in 6-1-2/5.5iii) TABLE 2 Class Factors to be Used in 6-1-2/5.5iv) TABLE 3 Peak Pressure Factors TABLE 4 Hull Area Factors (AF) for Vessels Intended to Operate

Ahead Only TABLE 5 Hull Area Factors (AF) for Vessels Intended to Operate

Ahead and Astern TABLE 6 Hull Area Factors (AF) for Vessels with Additional Notation

Ice Breaker and Intended to Operate Ahead Only TABLE 7 Hull Area Factors (AF) for Vessels with Additional Notation

Ice Breaker and Intended to Operate Ahead and Astern TABLE 8 Corrosion/Abrasion Additions for Shell Plating for Vessels

Intended to Operate Ahead Only TABLE 9 Corrosion/Abrasion Additions for Shell Plating for Vessels

Intended to Operate Ahead and Astern TABLE 10 Material Classes for Structural Members of Polar Class

Vessels TABLE 11 Steel Grades for Weather Exposed Plating TABLE 12 Longitudinal Strength Criteria

FIGURE 1 Hull Area Extents FIGURE 2 Definition of Hull Angles FIGURE 3 Shell Framing Angle Ω FIGURE 4 Stiffener Geometry FIGURE 5 Parameter Definition for Web Stiffening FIGURE 6 Steel Grade Requirements for Submerged and Weather

Exposed Shell Plating FIGURE 7 Bow Shape Definition FIGURE 8 Illustration of eb Effect on the Bow Shape for B = 20 and

LB = 16

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017 3

SECTION 3 Machinery Requirements for Polar Class Vessels 1 Application 3 Drawings and Particulars to be Submitted

3.1 Environmental Conditions

3.3 Drawings

3.5 Description Detailing

3.7 Calculations and Documentation

5 System Design

5.1 General

5.3 Governmental Authority

5.5 Damage by Freezing

5.7 Propeller Damage

5.9 Turning Gear

7 Materials

7.1 Materials Exposed to Sea Water

7.3 Materials Exposed to Sea Water Temperature

7.5 Materials Exposed to Low Air Temperature

9 Ice Interaction Load

9.1 Propeller-Ice Interaction

9.3 Ice Class Factors

9.5 Design Ice Loads for Open Propeller

9.7 Design Ice Loads for Ducted Propeller

9.9 Propeller Blade Loads and Stresses for Fatigue Analysis

9.11 Design Loads on Propulsion Line

11 Design

11.1 Design Principles

11.3 Azimuthing Main Propulsors

11.5 Propeller Blade Design

11.7 Blade Flange, Bolts and Propeller Hub and CP Mechanism

11.9 Propulsion Line Components

11.11 Prime Movers

13 Machinery Fastening Loading Accelerations

13.1 General

13.3 Longitudinal Impact Accelerations

13.5 Vertical Acceleration

13.7 Transverse Impact Acceleration

15 Auxiliary Systems

15.1 Machinery Protection

15.3 Freezing

15.5 Vent and Discharge Pipes

17 Sea Inlets and Cooling Water Systems

17.1 Cooling Water Systems for Machinery

17.3 Sea Chests

17.5 Ice Boxes

17.7 Sea Inlet Valves

17.9 Vent Pipes

17.11 Sea Bays Freezing Prevention

4 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017

17.13 Cooling Seawater Re-circulation

17.15 Ice Boxes Access

17.17 Openings in Vessel Sides

19 Ballast Tanks 21 Ventilation System

21.1 Air Intakes Location

21.3 Air Intakes Heating

21.5 Machinery Air Intakes

23 Steering Systems

23.1 General

23.3 Rudder Actuator Holding Torque

23.5 Torque Relief Arrangements

23.7 Fast Acting Torque Relief Arrangements

25 Alternative Designs

TABLE 1 Design Ice Thickness and Ice Strength Index TABLE 2 Load Cases for Open Propeller TABLE 3 Load Cases for Ducted Propeller TABLE 4 Parameters Cq and αi TABLE 5 Propeller Bollard Thrust TABLE 6 Reference Number of Impacts Per Propeller Rotation

Speed for Each Ice Class TABLE 7 Mean Fatigue Strength, σFat-E7, for Different Material

Types TABLE 8 Rudder Actuator Holding Torque Multipliers TABLE 9 Assumed Turning Speeds for Torque Relief Arrangements ... 73 TABLE 10 Rudder Actuator Holding Torque Multipliers

FIGURE 1 Shape of the Propeller Ice Torque Excitation for 90° and

135° Single Blade Impact Sequences and 45° Double Blade Impact Sequence (Figures Apply for Propellers with Four Blades)

FIGURE 2 Definitions of Peak Torque and Torque Amplitude FIGURE 3 Ice Load Distribution for Ducted and Open Propeller FIGURE 4 Cumulative Torque Distribution FIGURE 5 Example of Ice Load Distribution for the Shafting (k = 1), Divided Into Load Blocks FIGURE 6 Log-log Torque-cycle Diagram Defining TKmax1 FIGURE 7 Log-log Torque-cycle Diagram Defining ΔTKmax FIGURE 8 Log-log Torque-cycle Diagram Defining TKV

SECTION 4 Requirements for Enhanced Polar Class Notation

1 General

1.1 Application

3 Transverse Framing

3.1 Main and Intermediate Frames

3.3 Web Frames

3.5 Ice Stringers

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017 5

5 Longitudinal Framing

5.1 Struts

7 Peak Frames 9 Double Bottom

9.1 Inner Bottom

9.3 Transversely Framed Bottom

9.5 Longitudinally Framed Bottom

11 Ice Decks

11.1 General

11.3 Deck Plating

11.5 Deck Transverses and Deck Beams

11.7 Decks with Wide Openings

13 Bulkheads

13.1 General

13.3 Scantlings

15 Stem and Stern Frames

15.1 General

15.3 Stem

15.5 Stern Frame

17 Towing Arrangements

17.1 Bow

17.3 Stern

19 Machinery Arrangements

19.1 Propulsion Arrangements

19.3 Electric Propulsion

19.5 Boilers

19.7 Protection Against Excessive Torques

19.9 Propeller Arrangements

19.11 Tunnel Thrusters

19.13 Cooling Water Arrangements

19.15 Starting-air System

21 Power of Propulsion Machinery

21.1 Minimum Powering Criteria

21.3 Maximum Thickness of Consolidated Level Ice

21.5 Total Power Delivered to Propellers

21.7 Powering Criteria Obtained from Ice Model Tests

21.9 Astern Power

23 Flexible Couplings 25 Bossings 27 Rudder and Steering Arrangements

27.1 General

27.3 Rudder Stocks, Couplings and Pintles

27.5 Double Plate Rudder

29 Propeller Nozzles

29.1 General

29.3 Design Ice Forces

29.5 Plate Thickness

6 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017

31 Hull Structural Materials

31.1 Inspection

TABLE 1 Distance d, m (ft) TABLE 2 Maximum Stringer Spacing, m (ft) TABLE 3 Minimum Width of Reinforced Bulkhead Plating TABLE 4 Solid Stem Bar Coefficients TABLE 5 Stern Post Coefficient TABLE 6 Corrosion/Abrasion Additions for Shell Plating Around

Chock TABLE 7 Nominal Values of Powering Criteria TABLE 8 Power Coefficients TABLE 9 Design Speed for Rudders, Couplings and Pintles TABLE 10 Design Ice Force Coefficient TABLE 11 Corrosion/Abrasion Additions for Nozzle Surface Plating

FIGURE 1 Upper End Terminations of Frames FIGURE 2 Lower End Terminations of Frames FIGURE 3 Flare Angle Between Side Shell Line and CP at DWL

SECTION 5 Requirements for Vessels Intended for Navigation in First-year

Ice 1 General

1.1 Application

3 Selection of Ice Class

3.1 Ice Class

3.3 Guide for Selection

5 Definitions

5.1 Ice Belt

5.3 Upper Ice Waterline

5.5 Lower Ice Waterline

5.7 Displacement

5.9 Length

7 Extent and Length of Ice Belt Areas 9 Design Ice Loads

9.1 Design Ice Pressure on the Bow Area

9.3 Design Ice Pressures on Other Ice Belt Areas

9.5 Extent of Design Ice Load

11 Shell Plating

11.1 Ice Belt with Transverse Framing

11.3 Ice Belt with Longitudinal Framing

11.5 Changes in Plating Thickness

13 Transverse Framing

13.1 Definitions

13.3 Ice Belt Frame Spacing

13.5 Main and Intermediate Frames

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017 7

13.7 Web Frames

13.9 Ice Stringers

15 Longitudinal Framing

15.1 Spacing of Longitudinals

15.3 Section Modulus

15.5 Web Frames

15.7 Struts

17 Alternative Framing Arrangements 19 Peak Frames 21 Double Bottom

21.1 Longitudinally Framed Bottom

23 Ice Decks

23.1 General

23.3 Deck Plating

23.5 Deck Transverses and Deck Beams

23.7 Decks with Wide Openings

25 Bulkheads

25.1 Scantlings

27 Stem and Stern Frame

27.1 General

27.3 Stem

27.5 Stern Frame

29 Power of Propulsion Machinery

29.1 Minimum Power

29.3 Astern Power

31 Non-self-propelled Vessels

31.1 General

31.3 Ice Classes

31.5 Ice Belt

31.7 Design Ice Loads

31.9 Structural Arrangements

33 Hull Structural Materials

33.1 General

33.3 Design Service Temperature

33.5 Material Class of Structural Members

33.7 Criteria for ABS Grade Steels

33.9 Criteria for Other Steels

33.11 Weld Metal

35 Weld Design 37 Towing Arrangements

37.1 Bow

39 Propeller Nozzles

39.1 General

39.3 Design Ice Forces

39.5 Plate Thickness

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41 Rudder and Steering Arrangements

41.1 General

41.3 Rudder Stocks, Couplings and Pintles

41.5 Double Plate Rudder

43 Bossings 45 Machinery Arrangements

45.1 General

45.3 Governmental Authority

45.5 Propulsion Arrangements

45.7 Electric Propulsion

45.9 Boilers

45.11 Protection Against Excessive Torques

45.13 Sea Chests

47 Materials for Propellers and Propulsion Shafting 49 Determination of Ice Torque for Propulsion Systems 51 Propellers

51.1 Propeller Arrangements

51.3 Propeller Section

51.5 Additional Requirements

51.7 Friction Fitting of Propeller Hubs and Shaft Couplings

53 Propulsion Shafting Diameters 55 Reduction Gears 57 Flexible Couplings

TABLE 1 Regions and Periods for Navigation in Ice for Selecting Ice

Class TABLE 2 Ice Conditions of First-Year Ice Versus Concentration and

Thickness of Ice Cover TABLE 3 Dimensions of Ice Belt Areas, m (ft) TABLE 4 Bow Area Ice Pressure Coefficients TABLE 5 Ice Pressure Coefficients in Other Areas TABLE 6 Extent of Ice Load Coefficients TABLE 7 Minimum Thickness and Abrasion Allowance of Ice Belt

Plating TABLE 8a Coefficient K1 for the Framing System without Supporting

Stringers TABLE 8b Distance, m (ft) TABLE 9 Maximum Stringer Spacing, m (ft) TABLE 10 Minimum Width of Reinforced Bulkhead Plating TABLE 11 Solid Stem Bar Coefficients TABLE 12 Stern Post Coefficient TABLE 13 Power Coefficients TABLE 14 Ice Conditions for Towing or Pushing Barges TABLE 15 Design Service Temperature, degrees C (degrees F) TABLE 16 Material Class of Structural Members TABLE 17a Material Grades – Class I

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017 9

TABLE 17b Material Grades – Class II TABLE 17c Material Grade – Class III TABLE 18 Design Ice Force Coefficient TABLE 19 Design Speed for Rudders, Couplings and Pintles TABLE 20 Value of Ice Torque M TABLE 21 Values of m TABLE 22 Propulsion Shaft Diameter Factor k1

FIGURE 1 Ice Belt Areas FIGURE 1a Ice Class A0 through C0 FIGURE 1b Ice Class D0 and E0 FIGURE 1c Definition of F FIGURE 2 Coefficients Fb1 Versus angles αb and βb FIGURE 3 Upper End Terminations of Frames FIGURE 4 Lower End Terminations of Frames

SECTION 6 Baltic Ice Classes

1 General

1.1 Application

1.3 Area of Operation

1.5 Additional Guidance

3 Assignment of Ice Class

3.1 Ice Class

3.3 General Suitability for Operating in Ice

3.5 General Suitability for Winter Conditions

5 Definitions

5.1 Ice Belt

5.3 Upper and lower Ice Waterlines

5.5 Main Frame

5.7 Propulsion Machinery Output

7 Maximum and Minimum Draft Fore and Aft 9 Power of Propulsion Machinery

9.1 Propulsion Machinery Output, Ice Classes I AA, I A, I B

and I C

11 Hull Structural Design

11.1 Application

11.3 Hull Regions

11.5 Vertical Extent of Design Ice Pressure

11.7 Design Ice Pressure

13 Shell Plating

13.1 Vertical Extent of Ice Strengthening for Plating (Ice Belt)

13.3 Ice Belt Plating Thickness

15 Framing

15.1 General

15.3 Vertical Extent of Ice Strengthening for Framing

15.5 Transverse Framing

15.7 Longitudinal Framing

10 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017

17 Ice Stringers

17.1 Stringers within the Ice Belt

17.3 Stringers Outside the Ice Belt

17.5 Deck Strips

19 Web Frames

19.1 Design Ice Load

19.3 Section Modulus and Shear Area

21 Bow

21.1 Stem

23 Stern 25 Rudder and Steering Arrangements

25.1 Minimum Design Speed

25.3 Double Plated Rudders

25.5 Rudder and Rudder Stock Protection

25.7 Overload Design

27 Propulsion Machinery

27.1 Scope

27.3 Symbols

27.5 Design Ice Conditions

27.7 Materials

27.9 Design Loads

27.11 Design

27.13 Alternative Design

29 Additional Ice Strengthening Requirements

29.1 Starting Arrangements

29.3 Sea Inlet Chests for Cooling Water Systems and Fire Main

TABLE 1 Definition of Loads TABLE 2 Types of Ice Operation TABLE 3 Thickness of the Ice Block (Hice) TABLE 4 Load Cases for Open Propellers TABLE 5 Load Cases for Ducted Propellers TABLE 6 Coefficients C TABLE 7 Value for the G Parameter for Different m/k Ratios

FIGURE 1 Vessels' Dimensions FIGURE 2 Ice Load Distribution on Ship’s Side FIGURE 3 Definition of the Frame Span and Frame Spacing for

Curved Members FIGURE 4 Ice Strengthened Regions of the Hull FIGURE 5 Web Frame Model FIGURE 6 Examples of Suitable Ice Stems FIGURE 7 Direction of the Backward Blade Force Resultant Taken

Perpendicular to Chord Line at 0.7r/R FIGURE 8 The Weibull-type Distribution (Probability of Exceeding)

That is Used for Fatigue Design

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017 11

FIGURE 9 Shape of the Propeller Ice Torque Excitation for 90- and 135-Degree Single-blade Impact Sequences and 45-Degree Double Blade Impact Sequence

FIGURE 10 Two-slope S-N Curve FIGURE 11 Constant-slope S-N Curve

SECTION 6 Appendix 1 – Ice Class Draft Marking

FIGURE 1 Ice Class Draft Marking

SECTION 6 Appendix 2 – The Validity of the Powering Requirement in

6-1-6/9.1.2 TABLE 1 The Range of Parameters Used for Validation of the

Powering Requirement

12 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017

P A R T F o r e w o r d

C H A P T E R 1 Strengthening for Navigation in Ice

Foreword (2012) This Chapter provides requirements for optional ice strengthening classes. Sections 6-1-1 through 6-1-3 contain Polar Class ice strengthening requirements, based on IACS UR I1, I2, and I3, for vessels intended for operation in ice-covered Polar waters. Section 6-1-4 contains requirements for Enhanced Polar Class notation. Section 6-1-5 contains general ice strengthening requirements for vessels intended for navigation in first-year ice. Section 6-1-6 represents 1985 Finnish Swedish Ice Class Rules, as amended.

The requirements in this Section are applicable to vessels of any length and are in addition to those in other Sections of these Rules or Rules for Building and Classing Steel Vessels Under 90 Meters (295 Feet) in Length, as appropriate.

Vessels intended for navigation in the Canadian Arctic are to comply with the requirements of the Canadian Arctic Shipping Pollution Prevention Regulations. ABS can issue an Arctic Pollution Prevention Certificate when authorized by the Canadian flag administration.

It is the responsibility of the owner to determine which ice class is most suitable for the intended service.

With publication of this edition of the Rules, the IACS Unified Requirements for Polar Class Ships (April 2016) are incorporated into Sections 6-1-1 through 6-1-3, replacing the requirements of the previous ABS general ice classes: A5 through A1. Where the IACS requirements do not have a requirement comparable to an existing ABS requirement, the ABS requirement has been retained in Section 6-1-4 for an optional Enhanced notation.

With these changes, the ice strengthening requirements for general ice classes A0, B0, C0, D0, and E0 and for non-self-propelled vessels have been retained in Section 6-1-5.

The attention of designers, owners and operators is directed to the optional ABS Guide for Vessels Operating in Low Temperature Environments for considerations not covered in this Chapter. Further, IMO statutory instruments having requirements specific to cold regions operations also is to be considered.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017 13

P A R T S e c t i o n 1 : I n t r o d u c t i o n

C H A P T E R 1 Strengthening for Navigation in Ice

S E C T I O N 1 Introduction (2012)

1 General The ice classes are as follows in 6-1-1/Table 1.

TABLE 1

Ice Class Notations(2) (1 July 2017)

Polar Class (6-1-1, 6-1-2, 6-1-3)

Polar Class (6-1-1, 6-1-2, 6-1-3)

Polar Class, Enhanced (6-1-4)

First-year Ice Class (6-1-5)

Baltic Class (6-1-6)

PC1 Ice Breaker, PC1 PC1, Enhanced PC2 Ice Breaker, PC2 PC2, Enhanced PC3 Ice Breaker, PC3 PC3, Enhanced PC4 Ice Breaker, PC4 PC4, Enhanced PC5 Ice Breaker, PC5 PC5, Enhanced PC6 Ice Breaker, PC6 PC6, Enhanced I AA PC7 Ice Breaker, PC7 PC7, Enhanced A0 I A

B0 I B C0 I C D0 E0

Notes:

1 The shaded ice classes are eligible for Ice Breaker class notation.

2 (1 July 2017) This table shows the approximate correspondence between different ABS ice class notations. It is not to be interpreted to imply direct equivalencies between ice classes.

1.1 Application – Polar Class (1 July 2017)

i) The requirements for Polar Class Vessels apply to vessels constructed of steel and intended for independent navigation in ice-infested polar waters.

ii) Vessels that comply with the requirements of this Section, 6-1-1 and 6-1-2 can be considered for a Polar Class notation as listed in 6-1-1/Table 2. The requirements of these Sections are in addition to the open water requirements of the Rules. If the hull and machinery are constructed such as to comply with the requirements of different Polar Classes, then both the hull and machinery are to be assigned the lower of these classes in the Certificate of Classification. Compliance of the hull or machinery with the requirements of a higher Polar Class is also to be indicated in the Certificate of Classification.

iii) Vessels requiring ice breaker assistance are to comply with the additional requirements in 6-1-4/17.1.

iv) Provided all Polar Class Vessel requirements as specified in this Chapter are met, the vessels will be distinguished in the Record by Ice Class followed by ice class PC 7 through PC 1, as applicable.

14 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017

Part 6 Specialized Items and Systems Chapter 1 Strengthening for Navigation in Ice Section 1 Introduction 6-1-1

v) Vessels which are assigned a Polar Class notation and complying with the relevant requirements of Sections 6-1-1, 6-1-2 and 6-1-3 may be given the additional notation Ice Breaker. Ice Breaker refers to any vessel having an operational profile that includes escort or ice management functions, having powering and dimensions that allow it to undertake aggressive operations in ice-covered waters. These vessels are to be distinguished in the Record by the notation Ice Breaker followed by an appropriate Ice Class notation in 6-1-1/3.1 (e.g., À A1, Ice Breaker, Ice Class PC3)

vi) For vessels which are assigned a Polar Class notation, the hull form and propulsion power are to be such that the ship can operate independently and at continuous speed in a representative ice condition, as defined in 6-1-1/Table 2 for the corresponding Polar Class. For vessels and vessel-shaped units which are intentionally not designed to operate independently in ice, such operational intent or limitations are to be explicitly stated in the Certificate of Classification.

vii) For vessels which are assigned a Polar Class notation PC1 through PC5, bows with vertical sides, and bulbous bows are generally to be avoided. Bow angles should in general be within the range specified in 6-1-2/5.1v).

viii) For vessels which are assigned a Polar Class notation PC6 and PC7, and are designed with a bow with vertical sides or bulbous bows, operational limitations (restricted from intentional ramming) in design conditions are to be stated in the Certificate of Classification.

3 Description of Polar Class

3.1 Selection of Polar Classes

The Polar Class (PC) notations and descriptions are given in 6-1-1/Table 2. It is the responsibility of the Owner to select an appropriate Polar Class. The descriptions in 6-1-1/Table 2 are intended to guide owners, designers and administrations in selecting an appropriate Polar Class to match the requirements for the vessel with its intended voyage or service.

The Polar Class notations are used throughout this Chapter to convey the differences between classes with respect to operational capability and strength.

TABLE 2

Polar Class Descriptions (2012)

Polar Class Ice Description (based on WMO Sea Ice Nomenclature) PC1 Year-round operation in all Polar waters PC2 Year-round operation in moderate multi-year ice conditions PC3 Year-round operation in second-year ice which may include multi-year ice inclusions.

PC4 Year-round operation in thick first-year ice which may include old ice* inclusions PC5 Year-round operation in medium first-year ice which may include old ice* inclusions PC6 Summer/autumn operation in medium first-year ice which may include old ice* inclusions PC7 Summer/autumn operation in thin first-year ice which may include old ice* inclusions

* Note: “Old ice” means 2nd year ice or multi-year ice.

5 Definitions

5.1 Ice Belt

The ice belt is that reinforced portion of the shell and hull appendages that overlaps the upper and lower ice waterlines and is subject to the design ice loads. The required ice belt overlap extends from 1.5 m below the lower ice waterline to 1.0 m or 1.5 m above the upper ice waterline, depending upon Polar Class.

In the bow area, the overlap increases linearly to 2.0 m above the upper ice waterline at the stem. See 6-1-2/Figure 1.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017 15

Section 1 Introduction 6-1-1

5.3 Upper and Lower Ice Waterlines (1 July 2017)

The upper and lower ice waterlines upon which the design of the vessel has been based are to be indicated on the Certificate of Classification. The upper ice waterline (UIWL) is to be defined by the maximum drafts fore, amidships and aft. The lower ice waterline (LIWL) is to be defined by the minimum drafts fore, amidships and aft.

The lower ice waterline is to be determined with due regard to the vessel’s ice-going capability in the ballast loading conditions. The propeller is to be fully submerged at the lower ice waterline.

5.5 Displacement

The displacement, D, is the molded displacement in metric tons (long tons) at the upper ice waterline.

5.7 Length

The vessel’s length, L, is as defined in 3-1-1/3.1, but measured on the upper ice waterline, in m (ft).

16 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017

P A R T S e c t i o n 2 : S t r u c t u r a l R e q u i r e m e n t s f o r P o l a r C l a s s V e s s e l s

C H A P T E R 1 Strengthening for Navigation in Ice

S E C T I O N 2 Structural Requirements for Polar Class Vessels (2012)

1 Application These requirements apply to Polar Class vessels according to 6-1-1/1.1.

3 Hull Areas

3.1 General

i) The hull of all Polar Class vessels is divided into areas reflecting the magnitude of the loads that are expected to act upon them. In the longitudinal direction, there are four regions: Bow, Bow Intermediate, Midbody and Stern. The Bow Intermediate, Midbody and Stern regions are further divided in the vertical direction into the Bottom, Lower and Icebelt regions. The extent of each Hull Area is illustrated in 6-1-2/Figure 1.

ii) The upper ice waterline (UIWL) and lower ice waterline (LIWL) are as defined in 6-1-1/5.3.

iii) 6-1-2/Figure 1 notwithstanding, at no time is the boundary between the Bow and Bow Intermediate regions to be forward of the intersection point of the line of the stem and the vessel baseline.

iv) 6-1-2/Figure 1 notwithstanding, the aft boundary of the Bow region need not be more than 0.45L aft of the forward perpendicular (FP).

v) The boundary between the bottom and lower regions is to be taken at the point where the shell tangent is inclined 7 degrees from horizontal.

vi) If a vessel is intended to operate astern in ice regions, the aft section of the vessel is to be designed using the Bow and Bow Intermediate hull area requirements as prescribed in 6-1-2/3.1vii).

vii) (1 July 2017) 6-1-2/Figure 1 notwithstanding, if the vessel is assigned the additional notation Ice Breaker, the forward boundary of the stern region is to be at least 0.04L forward of the section where the parallel ship side at the upper ice waterline (UIWL) ends.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017 17

Section 2 Structural Requirements for Polar Class Vessels 6-1-2

18 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017

FIGURE 1

Hull Area Extents (2012)

B x

BIi

BI1

Mi

M1

Si

S1

WL Angle = 10 degrees at UIWL 0.04L aft of WL Angle = 0 degrees at UIWL

WL Angle = 0 degrees

WL Angle = 10 degrees

For PC1, 2, 3 & 4 x = 1.5 m (1.5 m, 59 in.)

For PC5, 6 & 7 x = 1.0 m (1.0 m, 39 in.)

with "x" measured at aft end of bow region

2.0 m (2.0 m, 79 in.)

0.7b => 0.15L

1.5 m (1.5 m, 59 in.)

AP

b = distance from AP to maximum half breadth at UIWL

BBIb

BI1

Si S1

Sb Mb

M1

Mi

M1 Mb

UIWL

LIWL

Midbody

UIWL

LIWL

5 Design Ice Loads

5.1 General (1 July 2017)

i) A glancing impact on the bow is the design scenario for determining the scantlings required to resist ice loads.

ii) The design ice load is characterized by an average pressure (Pavg) uniformly distributed over a rectangular load patch of height (b) and width (w).

iii) Within the Bow area of all Polar Class vessels, and within the Bow Intermediate Icebelt area of Polar Class PC6 and PC7, the ice load parameters are functions of the actual bow shape. To determine the ice load parameters (Pavg, b and w), it is required to calculate the following ice load characteristics for sub-regions of the bow area; shape coefficient (fai), total glancing impact force (Fi), line load (Qi) and pressure (Pi).

iv) In other ice-strengthened areas, the ice load parameters (Pavg, bNonBow and wNonBow) are determined independently of the hull shape and based on a fixed load patch aspect ratio, AR = 3.6.

v) Design ice forces calculated according to 6-1-2/5.5iii) are applicable for bow forms where the buttock angle at the stem is positive and less than 80°, and the normal frame angle at the center of the foremost sub-region, as defined in 6-1-2/5.5i), is greater than 10°.

vi) Design ice forces calculated according to 6-1-2/5.5iv) are applicable for ships which are assigned the Polar Class PC6 or PC7 and have a bow form with vertical sides. This includes bows where the normal frame angles at the considered sub-regions, as defined in 6-1-2/5.5i), are between 0° and 10°.

vii) For ships which are assigned the Polar Class PC6 or PC7, and equipped with bulbous bows, the design ice forces on the bow are to be determined according to 6-1-2/5.5iv). In addition, the design forces are not to be taken less than those given in 6-1-2/5.5iii), assuming fa = 0.6 and AR = 1.3.

viii) For ships with bow forms other than those defined in 6-1-2/5.1v) to 6-1-2/5.1vii), design forces are to be specially considered.

ix) Vessel structures that are not directly subjected to ice loads may still experience inertial loads of stowed cargo and equipment resulting from ship/ice interaction. These inertial loads, based on the maximum accelerations as given in 6-1-3/13, are to be considered in the design of these structures.

5.3 Glancing Impact Load Characteristics (1 July 2017)

The parameters defining the glancing impact load characteristics are reflected in the Class Factors listed in 6-1-2/Table 1 and 6-1-2/Table 2.

TABLE 1

Class Factors to be Used in 6-1-2/5.5iii) (1 July 2017)

Polar Class

Crushing Failure

Class Factor

(CFC)

Flexural Failure

(CFF)

Load Patch Dimensions

(CFD)

Displacement

(CFDIS)

Longitudinal Strength

Class Factor

(CFL)

PC1 17.69 (1804 ,1794) 68.60 (6995 ,6885) 2.01 (0.122 ,0.308) 250 (250 ,246) 7.46 (753,473) PC2 9.89 (1009 ,1003) 46.80 (4772 ,4697) 1.75 (0.1062 ,0.268) 210 (210 ,207) 5.46 (551, 346) PC3 6.06 (618 ,614) 21.17 (2159 ,2125) 1.53 (0.093 ,0.234) 180 (180 ,177) 4.17 (421, 264) PC4 4.50 (459 ,456) 13.48 (1375 ,1353) 1.42 (0.086 ,0.218) 130 (130 ,128) 3.15 (318, 200) PC5 3.10 (316 ,314) 9.00 (918 ,903) 1.31 (0.080 ,0.201) 70 (70 ,69) 2.50 (252, 158) PC6 2.40 (245 ,243) 5.49 (560 ,551) 1.17 (0.071 ,0.179) 40 (40 ,39) 2.37 (239, 150) PC7 1.80 (184 ,183) 4.06 (414 ,407) 1.11 (0.0673 ,0.170) 22 (22 ,22) 1.81 (183, 115)

Note on Units: There are 3 system of units employed in this document. The first is SI, as is used in the IACS Unified Requirement. The second is the MKS system, and the third is the US customary units. In the document units and constants will be shown as SI (MKS, US), as for example: MPa (kgf/mm2, psi). In many cases the SI and MKS values are the same, but 3 values are always given for complete clarity.

TABLE 2

Class Factors to be Used in 6-1-2/5.5iv) (1 July 2017)

Polar Class

Crushing Failure Class Factor

(CFCV)

Line Load Class Factor

(CFQV)

Pressure Class Factor

(CFPV)

PC6 3.43 (350, 347) 2.82 (1.039, 2.608) 0.65 (0.00497, 7.137)

PC7 2.60 (265, 263) 2.33 (0.859, 2.155) 0.65 (0.00497, 7.137)

5.5 Bow Area

i) In the Bow area, the force (F), line load (Q), pressure (P) and load patch aspect ratio (AR) associated with the glancing impact load scenario are functions of the hull angles measured at the upper ice waterline (UIWL). The influence of the hull angles is captured through calculation of a bow shape coefficient (fa). The hull angles are defined in 6-1-2/Figure 2.

ii) The waterline length of the bow region is generally to be divided into four sub-regions of equal length. The force (F), line load (Q), pressure (P) and load patch aspect ratio (AR) are to be calculated with respect to the mid-length position of each sub-region (each maximum of F, Q and P is to be used in the calculation of the ice load parameters Pavg, b and w).

iii) (1 July 2017) The Bow area load characteristics for bow forms defined in 6-1-2/5.1v) are determined as follows:

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017 19

FIGURE 2

Definition of Hull Angles (2012)

A

A B

B αwaterline plan waterline angle α buttock angle γ sheer plan γ body plan A-A section B-B β β ′ normal frame angle β ′frame angle β Note: β ′ = normal frame angle at upper ice waterline, degrees α = upper ice waterline angle, degrees γ = buttock angle at upper ice waterline (angle of buttock line measured from horizontal), degrees tan(β) = tan(α)/tan(γ) tan(β ′) = tan(β) cos(α)

5.5.1 Shape Coefficient

Shape coefficient, fai, is to be taken as:

fai = minimum (fai,1; fai,2; fai,3) where fai,1 = [0.097 – 0.68 (x/L – 0.15)2] ⋅ αi/( iβ ′ )0.5 fai,2 = 1.2 ⋅ CFF/(sin ( iβ ′ ) ⋅ CFC ⋅ D0.64) fai,3 = 0.60 i = sub-region considered

L = vessel length as defined in 6-1-1/5.7, in m (m, ft) x = distance from the forward perpendicular (FP) to station under consideration, in m (m, ft) α = waterline angle, in degrees, see 6-1-2/Figure. 2 β′ = normal frame angle, in degrees, see 6-1-2/Figure 2

D = vessel displacement, in kt (kt, kLt), not to be taken less than 5 kt (5 kt, 5 kLt) See 6-1-1/5.5

CFC = Crushing Failure Class Factor from 6-1-2/Table 1

CFF = Flexural Failure Class Factor from 6-1-2/Table 1

5.5.2 Force

Force, F, in MN (tf, Ltf) is to be taken as:

Fi = fai ⋅ CFC ⋅ D0.64 where i = sub-region considered fai = shape coefficient of sub-region i

CFC = Crushing Failure Class Factor from 6-1-2/Table 1

D = vessel displacement, in kt (kt, kLt), not to be taken less than 5 kt (5 kt, 4.9 kLt)

20 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017

5.5.3 Load Patch Aspect Ratio

Load patch aspect ratio, AR, is to be taken as:

ARi = 7.46 ⋅ sin ( iβ ′ ) ≥ 1.3 where i = sub-region considered iβ ′ = normal frame angle of sub-region i, in degrees

5.5.4 Line Load

Line load, Q, in MN/m (tf/cm, Ltf/in) is to be taken as:

Qi = Fi

0.61 ⋅ CFD/ARi

0.35 where i = sub-region considered

Fi = force of sub-region i, in MN (tf, Ltf)

CFD = Load Patch Dimensions Class Factor from 6-1-2/Table 1

ARi = load patch aspect ratio of sub-region i

5.5.5 Pressure

Pressure, P, in MPa (kgf/mm2, psi) is to be taken as:

Pi = c1 ⋅ Fi

0.22 ⋅ CFD

2 ⋅ ARi 0.3 where i = sub-region considered

Fi = force of sub-region i, in MN (tf, Ltf)

CFD = Load Patch Dimensions Class Factor from 6-1-2/Table 1

ARi = load patch aspect ratio of sub-region i c1 = 1 (10, 2240)

iv) (1 July 2017) The Bow area load characteristics for bow forms defined in 6-1-2/5.1vi) are determined as follows:

5.5.6 Shape Coefficient (1 July 2017)

fai = αi/30 where i = sub-region considered αi = waterline angle, in degrees, see 6-1-2/Figure 2

5.5.7 Force (1 July 2017)

Force, F, in MN (tf, Ltf) is to be taken as:

Fi = fai ⋅ CFCV ⋅ D0.47 where i = sub-region considered fai = shape coefficient of sub-region i

CFCV = Crushing Failure Class Factor from 6-1-2/Table 2

D = vessel displacement, in kt (kt, kLt), not to be taken less than 5 kt (5 kt, 4.9 kLt)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017 21

5.5.8 Line Load (1 July 2017)

Line load, Q, in MN/m (tf/cm, Ltf/in) is to be taken as:

Qi = Fi

0.22 ⋅ CFQV

where i = sub-region considered

Fi = force of sub-region i, in MN (tf, Ltf)

CFQV = Load Patch Dimensions Class Factor from 6-1-2/Table 2

5.5.9 Pressure (1 July 2017)

Pressure, P, in MPa (kgf/mm2, psi) is to be taken as:

Pi = Fi

0.56 ⋅ CFPV

where i = sub-region considered

Fi = force of sub-region i, in MN (tf, Ltf)

CFPV = Pressure Class Factor from 6-1-2/Table 2

5.7 Hull Areas Other Than the Bow

In the hull areas other than the bow, the force (FNonBow) and line load (QNonBow) used in the determination of the load patch dimensions (bNonBow, wNonBow) and design pressure (Pavg) are determined as follows:

5.7.1 Force

Force, FNonBow, in MN (tf, Ltf) is to be taken as:

FNonBow = 0.36 ⋅ CFC ⋅ DF where

CFC = Crushing Force Class Factor from 6-1-2/Table 1

DF = vessel displacement factor

= D0.64 if D ≤ CFDIS

= 64.0 DISCF + 0.10 (D – CFDIS) if D > CFDIS

D = vessel displacement, in kt (kt, kLt), not to be taken less than 10 kt (10 kt,

9.8 kLt). See 6-1-1/5.5

CFDIS = Displacement Class Factor from 6-1-2/Table 1

5.7.2 Line Load

Line Load, QNonBow, in MN/m (tf/cm, Ltf/in) is to be taken as:

QNonBow = 0.639 ⋅ 61.0 NonBowF ⋅ CFD where

FNonBow = force from 6-1-2/5.7.1, in MN (tf, Ltf)

CFD = Load Patch Dimensions Class Factor from 6-1-2/Table 1

22 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017

5.9 Design Load Patch

5.9.1 Bow Area

In the Bow area, and the Bow Intermediate Ice belt area for vessels with class notation PC6 and PC7, the design load patch has dimensions of width, wBow, and height, bBow, expressed in m (cm, in.)

and defined as follows:

i) wBow = FBow/QBow

ii) bBow = c1 QBow/PBow where

FBow = maximum Fi in the Bow area, in MN (tf, Ltf)

QBow = maximum Qi in the Bow area, in MN/m (tf/cm, Ltf/in)

PBow = maximum Pi in the Bow area, in MPa (kgf/mm2, psi) c1 = 1 (10, 2240)

5.9.2 Other Hull Areas

In hull areas other than those covered by 6-1-2/5.9.1, the design load patch has dimensions of width, wNonBow, and height, bNonBow, expressed in m (cm, in.) and defined as follows:

i) wNonBow = FNonBow/QNonBow

ii) bNonBow = wNonBow /3.6 where

FNonBow = force determined using 6-1-2/5.7.1, in MN (tf, Ltf)

QNonBow = line load determined using 6-1-2/5.7.2, in MN/m (tf/cm, Ltf/in)

5.11 Pressure within the Design Load Patch

5.11.1 Average Pressure

The average pressure, Pavg, in MPa (kgf/mm2, psi) within a design load patch is determined as follows:

Pavg = c1 F/(b ⋅ w) where

F = FBow or FNonBow as appropriate for the hull area under consideration, in MN (tf, Ltf) b = bBow or bNonBow as appropriate for the hull area under consideration, in m (cm, in.)

w = wBow or wNonBow as appropriate for the hull area under consideration, in m (cm, in.)

c1 = 1 (10, 2240)

5.11.2 Areas of Higher, Concentrated Pressure

Areas of higher, concentrated pressure exist within the load patch. In general, smaller areas have higher local pressures. Accordingly, the peak pressure factors listed in 6-1-2/Table 3 are used to account for the pressure concentration on localized structural members.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2017 23

TABLE 3

Peak Pressure Factors (1 July 2017)

Structur…