Foreword This Guide describes criteria to be used for drilling systems@ which are approved by the American Bureau of Shipping (ABS)@ and built to requirements of recognized codes and standards. This Guide is to be used in conjunction with other applicable ABS Rules and Guides@ codes and standards as referenced therein@ and applicable national regulations. ABS Classification continues to provide the offshore industry with a pathway toward agreement with Regulatory Authorities. Any Owner/Operator??s specific request for compliance with applicable requirements of flag or Coastal State Authorities affecting the drilling systems is to be filed as an addendum to the Request for Classification. The 2017 edition of the Guide for the Classification of Drilling Systems is an updated version of the 2012 edition of the subject Guide. The first edition of the CDS Guide was published in 1986 to support the drilling regulations developed for rigs operating in the UK sector of the North Sea. As part of ABS??s commitment to promoting the security of life and property and preserving the natural environment@ ABS has endeavored to continuously update the Guide by applying the latest industry standards and trends in risk abatement. Previous Sections of this Guide have been reformatted to Chapters and each Chapter has been updated in accordance with the latest industry standards and practices as well as ABS plan review and survey practices. This Guide specifies only the unique requirements applicable to drilling systems. This Guide is always to be used with the ABS Rules for Conditions of Classification ?C Offshore Units and Structures (Part 1). The particular changes made to the Guide are as follows: