CHAPTER 4
AUXILIARY PROPULSION UNITS

TABLE OF CONTENTS

CERTIFICATION SHEET

RECORD OF CHANGES

SAFETY SUMMARY

SECTION 1 - INTRODUCTION

4-1.1    PURPOSE

4-1.2    SCOPE

4-1.3    REFERENCE DOCUMENTS

4-1.4    APU SYSTEM DESCRIPTION

4-1.5    PROBLEM IDENTIFICATION

4-1.5.1    Electrical Problems

4-1.5.2    Mechanical Problems

4-1.6    PLANNING AND PREPARATION

SECTION 2 - APU SYSTEM REPAIR AND REPLACEMENT PROCEDURES

4-2.1    PROCEDURES PROVIDED

4-2.2    APU MOTOR ASSEMBLY

4-2.3    COFFERDAM INSTALLATION PROCEDURES

4-2.4    APU MOTOR REMOVAL PROCEDURES

4-2.5    ELECTRICAL CABLE REPLACEMENT PROCEDURES

4-2.6    APU MOTOR REPLACEMENT

4-2.7    UNDERWATER REPLACEMENT OF APU PROPELLER

LIST OF APPENDICES

APPENDIX A

INSULATION RESISTANCE - TEMPERATURE NOMOGRAPH

APPENDIX B

FABRICATION AND ASSEMBLY DRAWINGS FOR SECONDARY SEAL STUDS, SECONDARY SEAL DISK, AND SECONDARY SEAL ASSEMBLY

APPENDIX C

DIVER ’S INSPECTION FORM (AUXILLARY PROPULSION UNIT INSPECTION DATA) NAVSEA 4730/8

APPENDIX D

NAVSEA APU KIT DRAWINGS

APPENDIX E

TEMPORARY SECONDARY SEAL ASSEMBLY

LIST OF ILLUSTRATIONS

4-1     Location of APU in FFG 7 Class Ships

4-2     APU Components

4-3     Training and Retracting Device with Brush and Slip Ring Assemblies Removed

4-3A   Tugit Lever Hoists (Harrington Pull-Chain Type have a two part Reeve)

4-4     Attachment of Support Column Fixture

4-5     Electrical Cable Disconnection

4-6     Installation of Special Seal Plugs and Caps

4-7     Installation of Top Hat Cover and Gasket

4-8     Installation of Fairing Plate on APU Motor

4-9     Access to Secondary Seal Disk

4-10   Attachment of Boat Winch Wire to Secondary Seal Disk

4-11   Electrical Cable Connection

4-12   Delrin Shaft Thread Protector

4-13   Propeller Puller Assembly

4-14   Propeller Rigging Attachment Point

4-15   Measurement of Initial and Final Installation Positions

A-1     Insulation Resistance - Temperature Nomograph

A-2     Example of Insulation Resistance - Temperature Correction

B-3     NAVSEA Drawing 6698226 Rev C – APU Secondary Seal Disk Assembly

           Misc. Hardware

B-5     NAVSEA Drawing 6698227 Rev C - APU Secondary Seal Electrode

B-7     NAVSEA Drawing 6698228 Rev A - APU Secondary Seal Electrode Assembly

B-9     NAVSEA Drawing 6698229 Rev D – APU Secondary Seal Disk Assembly

B-11   NAVSEA Drawing 6699609 Rev A - APU Secondary Seal Disk

C-3     Auxiliary Propulsion Unit Inspection Data Form

D-3     NAVSEA Drawing 6699482 Rev. I - APU Kit

D-9     NAVSEA Drawing 6699592 Rev. J - APU Removal Rigging Plan FFG 7

D-21   NAVSEA Drawing 6699484 Rev. D - APU Cofferdam Main Assembly FFG 7

           APU Kit

D-23   NAVSEA Drawing 6699576 Rev. E - APU Cofferdam Rubber FFG 7 APU Kit

D-25   NAVSEA Drawing 6699494 Rev. G - APU Secondary Seal Removal System

           FFG 7 APU Kit

D-29   NAVSEA Drawing 6699497 Rev. A - Nitrogen Drying System FFG 7 APU Kit

D-31   NAVSEA Drawing 6699603 Rev(-) - APU Prop Nut Removal Tool

           FFG 7 APU Kit

D-33   NAVSEA Drawing 6697724 Rev(-) - Alignment Fixtures Main Assembly FFG 7

           APU Kit

LIST OF TABLES

4-1   Equipment, Material, and Tools to be Provided by the Repair Activity