1、 ABSGUIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GASES IN BULK .2005 1 GUIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GASES IN BULK APRIL 2005 NOTICE NO. 1 July 2005 The following Changes were approved by the ABS Classification Committee (1-2/4 and 1-2/5) on 23 June 2005 and by the
2、 ABS Rules Committee (the rest of the changes) on 17 June 2005 and become EFFECTIVE AS OF 1 JULY 2005. (See http:/www.eagle.org/rules/downloads.html for the consolidated version of the Guide for Vessels Intended to Carry Compressed Natural Gases in Bulk 2005, updated in July 2005, with all Notices a
3、nd Corrigenda incorporated.) Notes - The date in the parentheses means the date that the Rule becomes effective for new construction based on the contract date for construction, unless otherwise noted. (See 1-4/2.2.) CHAPTER 1 SCOPE AND CONDITIONS OF CLASSIFICATION SECTION 2 SUSPENSION AND CANCELLAT
4、ION OF CLASSIFICATION (These Changes to the conditions of classification become effective on 1 July 2005.) (Revise 1-2/4 as follows.) 4 Suspension of Class (1 July 2005) Suspension of classification is a withdrawal of all representations by the Bureau as to a vessel or structure. Class will be suspe
5、nded and the Certificate of Classification will become invalid from the date of any use, operation or other application of any CNG carrier and its equipment for which it has not been approved and which affects or may affect classification or the structural integrity, quality or fitness for a particu
6、lar use or service. Class will be suspended and the Certificate of Classification will become invalid in any of the following circumstances: i) If recommendations issued by the Surveyor are not carried out by their due dates and no extension has been granted; ii) If Continuous Survey items which are
7、 due or overdue at the time of Annual Survey are not completed and no extension has been granted; iii) If the periodical surveys required for maintenance of class, other than Annual or Special Surveys, are not carried out by the due date and no Rule allowed extension has been granted; or iv) If any
8、damage, failure, deterioration or repair has not been completed as recommended. Notice No. 1 July 2005 2 ABSGUIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GASES IN BULK .2005 Class may be suspended, in which case the Certificate of Classification will become invalid, if proposed repairs as r
9、eferred to in 1-9/1 of this Guide have not been submitted to the Bureau and agreed upon prior to commencement. Class is automatically suspended and the Certificate of Classification is invalid in any of the following circumstances: i) If the Annual Survey is not completed by the date which is three
10、(3) months after the due date, unless the vessel is under attendance for completion of the Annual Survey, or ii) If the Special Periodical Survey is not completed by the due date, unless the vessel is under attendance for completion prior to resuming trading. Under “exceptional circumstances” (limit
11、ed to such cases as unavailability of drydocking facilities; unavailability of repair facilities; unavailability of essential materials, equipment or spare parts; or delays incurred by action taken to avoid severe weather conditions), consideration may be given for an extension of the Special Period
12、ical Survey not exceeding three (3) months, provided the vessel is attended and the attending Surveyor(s) so recommend(s) after the following has been carried out: Annual Survey; and Re-examination of recommendations; and Progression of the Special Periodical Survey as far as practicable; and In the
13、 case where drydocking is due prior to the end of the class extension, an underwater examination is to be carried out by an approved diving company. An underwater examination by an approved company may be dispensed with in the case of extension of Drydocking Survey not exceeding 36 months interval p
14、rovided the vessel is without outstanding recommendation regarding underwater parts. If the vessel is at sea on the Special Periodical Survey due date, consideration may be given for an extension of the Special Periodical Survey provided there is documented agreement to an extension prior to the due
15、 date, positive arrangements have been made for a Surveyor to attend the vessel at the first port of call, and the Bureau is satisfied there is technical justification for an extension; such an extension shall be granted only until arrival at the first port of call after the due date. However, if ow
16、ing to “exceptional circumstances” the Special Periodical Survey cannot be completed at the first port of call, the Rule above for an extension of the Special Periodical Survey may be followed, but the total period of extension shall in no case be longer than three (3) months after the original due
17、date of the Special Periodical Survey. When a vessel is intended for a demolition voyage with any periodical survey overdue, the vessels class suspension may be held in abeyance and consideration may be given to allow the vessel to proceed on a single direct ballast voyage from the lay up or final d
18、ischarge port to the demolition yard. In such cases a short term Class Certificate with conditions for the voyage noted may be issued provided the attending Surveyor finds the vessel in satisfactory condition to proceed for the intended voyage. Notice No. 1 July 2005 ABSGUIDE FOR VESSELS INTENDED TO
19、 CARRY COMPRESSED NATURAL GASES IN BULK .2005 3 (Revise 1-2/5 as follows.) 5 Lifting of Suspension (1 July 2005) Class will be reinstated after suspension for overdue surveys upon satisfactory completion of the overdue surveys. Such surveys will be credited as of the original due date. However, the
20、vessel is disclassed from the date of suspension until the date class is reinstated. Class will be reinstated after suspension for overdue recommendations upon satisfactory completion of the overdue recommendation. However, the vessel is disclassed from the date of suspension until the date class is
21、 reinstated. Class will be reinstated after suspension for overdue Continuous Survey items upon satisfactory completion of the overdue items. CHAPTER 3 SHIP SURVIVAL CAPABILITY AND LOCATION OF CARGO TANKS SECTION 2 FREEBOARD AND INTACT STABILITY (Add new Subsection 3-2/6, as follows.) 6 Onboard Comp
22、uters for Stability Calculations (1 July 2005) The use of onboard computers for stability calculations is not a requirement of class. However, if stability software is installed onboard vessels contracted on or after 1 July 2005, it should cover all stability requirements applicable to the vessel an
23、d is to be approved by the Bureau for compliance with the requirements of Appendix 3-3-A1, “Onboard Computers for Stability Calculations”. The hardware is to be either approved in accordance with the recognized standards*, or at least two computers are to be nominated and specifically provided with
24、software capable of performing stability calculations for the vessel. * Note: A guideline on hardware approval is available from IACS Recommendations No. 48, 3.2 “Stand-alone Computer Hardware” Notice No. 1 July 2005 4 ABSGUIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GASES IN BULK .2005 CHA
25、PTER 3 SHIP SURVIVAL CAPABILITY AND LOCATION OF CARGO TANKS APPENDIX 1 ONBOARD COMPUTERS FOR STABILITY CALCULATIONS (1 JULY 2005) (Add new Appendix 3-A1, as follows.) 1 General 1.1 Scope The scope of stability calculation software is to be in accordance with the stability information as approved by
26、the flag Administration or the Bureau on behalf of the flag Administration. The software is at least to include all information and perform all calculations or checks as necessary to ensure compliance with the applicable stability requirements. Approved stability software is not a substitute for the
27、 approved stability information, and is used as a supplement to the approved stability information to facilitate stability calculations. 1.2 Design The input/output information is to be easily comparable with approved stability information so as to avoid confusion and possible misinterpretation by t
28、he operator relative to the approved stability information. An operation manual is to be provided for the onboard computer stability software. The language in which the stability information is displayed and printed out as well as the operation manual is written is to be the same as used in the vess
29、els approved stability information. The primary language is to be English. The onboard computer for stability calculations is vessel specific equipment and the results of the calculations are only applicable to the vessel for which it has been approved. In case of modifications implying changes in t
30、he main data or internal arrangement of the vessel, the specific approval of any original stability calculation software is no longer valid. The software is to be modified accordingly and reapproved. 2 Calculation Systems This Appendix covers either system, a passive system that requires manual data
31、 entry or an active system, which replaces the manual with the automatic entry with sensors reading and entering the contents of tanks, etc., provided the active system is in the off-line operation mode. However, an integrated system, which controls or initiates actions based on the sensor-supplied
32、inputs is not within the scope of this Appendix. Notice No. 1 July 2005 ABSGUIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GASES IN BULK .2005 5 3 Types of Stability Software Three types of calculations performed by stability software are acceptable depending upon a vessels stability requirem
33、ents: Type 1 Software calculating intact stability only (for vessels not required to meet a damage stability criterion) Type 2 Software calculating intact stability and checking damage stability on basis of a limit curve or previously approved loading conditions Type 3 Software calculating intact st
34、ability and damage stability by direct application of preprogrammed damage cases for each loading condition 4 Functional Requirements 4.1 Calculation Program The calculation program is to present relevant parameters of each loading condition in order to assist the Master in his judgment on whether t
35、he vessel is loaded within the approval limits. The following parameters are to be presented for a given loading condition: Deadweight data Lightship data Trim Draft at the draft marks and perpendiculars Summary of loading condition displacement, VCG, LCG and, if applicable, TCG Downflooding angle a
36、nd corresponding downflooding opening Compliance with stability criteria: Listing of all calculated stability criteria, the limit values, the obtained values and the conclusions (criteria fulfilled or not fulfilled) 4.2 Direct Damage Stability Calculations If direct damage stability calculations are
37、 performed, the relevant damage cases according to the applicable rules are to be pre-defined for automatic check of a given loading condition. 4.3 Warning A clear warning is to be given on screen and in hard copy printout if any of the loading limitations are not complied with. 4.4 Data Printout Th
38、e data are to be presented on screen and in hard copy printout in a clear unambiguous manner. 4.5 Date and Time The date and time of a saved calculation are to be part of the screen display and hard copy printout. Notice No. 1 July 2005 6 ABSGUIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GAS
39、ES IN BULK .2005 4.6 Information of Program Each hard copy printout is to include identification of the calculation program with version number. 4.7 Units Units of measurement are to be clearly identified and used consistently within a loading calculation. 5 Acceptable Tolerances Depending on the ty
40、pe and scope of programs, the acceptable tolerances are to be determined differently, according to 3-A1/5.1 or 3-A1/5.2. In general, deviation from these tolerances is not to be accepted unless a satisfactory explanation for the difference is submitted for review and the same is satisfactorily confi
41、rmed by the Bureau that there would be no adverse effect on the safety of the vessel. Examples of pre-programmed input data include the following: Hydrostatic data: Displacement, LCB, LCF, VCB, KMt and MCT vs. draft Stability data: KN or MS values at appropriate heel/trim angles vs. displacement, st
42、ability limits. Compartment data: Volume, LCG, VCG, TCG and FSM heeling moments vs. level of the compartments contents. Examples of output data include the following: Hydrostatic data: Displacement, LCB, LCF, VCB, KMt and MCT versus draft, as well as actual drafts, trim. Stability data: FSC (free su
43、rface correction), GZ-values, KG, GM, KG/GM limits, derived stability criteria (e.g., areas under the GZ curve), weather criteria. Compartment data: Calculated Volume, LCG, VCG, TCG and FSM heeling moments vs. level of the compartments contents The computational accuracy of the calculation program r
44、esults is to be within the acceptable tolerances specified in 3-A3/5.1 or 3-A3/5.2, of the results using an independent program or the approved stability information with identical input. 5.1 Calculation Program of the Approved Stability Information Programs which use only pre-programmed data from t
45、he approved stability information as the basis for stability calculations are to have zero tolerances for the printouts of input data. Output data tolerances are to be close to zero. However, small differences associated with calculation rounding or abridged input data are acceptable. Additionally d
46、ifferences associated with the use of hydrostatic and stability data for trims that differ from those in the approved stability information are acceptable subject to review by the Bureau. 5.2 Independent Program for Assessment of Stability Programs which use hull form models as their basis for stabi
47、lity calculations are to have tolerances for the printouts of basic calculated data established against either data from the approved stability information or data obtained using the approval authoritys model. Acceptable tolerances shall be in accordance with 3-A1/Table 1. Notice No. 1 July 2005 ABS
48、GUIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GASES IN BULK .2005 7 TABLE 1 Acceptable Tolerances Hull Form Dependent Acceptable Tolerance (1)Displacement 2% Longitudinal center of buoyancy, from AP 1%/50 cm max Vertical center of buoyancy 1%/5 cm max Transverse center of buoyancy 0.5% of B
49、/5 cm max Longitudinal center of flotation, from AP 1%/50 cm max Moment to trim 1 cm 2% Transverse metacentric height 1%/5 cm max Longitudinal metacentric height 1%/50cm max Cross curves of stability 50 mm Compartment Dependent Volume or deadweight 2% Longitudinal center of gravity, from AP 1%/50 cm max Vertical centre of gravity 1%/5 cm max Transverse center of gravity 0.5% of B/5 cm max Free surface moment 2% Shifting moment 5% Level of contents 2% Trim and Stability Drafts (forward, aft, mean) 1%/5 cm max GMt 1%/5 cm max GZ values
