where the number 80064 identifies NAVSHIPS. In viewB, the number 80091 identifies the Naval Facilities3. The first part of the system command number isa three-digit group number. It is assigned from theConsolidated Index of Drawings, Materials, andServices Related to Construction and Conversion,NAVSHIPS 0902-002-2000. This number identifies theequipment or system, and sometimes the type of plan. In figure 1-1, view A, the number 800 under theNAVSHIP SYSTEM COMMAND NO. blockidentifies the plan as a contract plan. 4. The second part of the system command numberis the serial or file number assigned by the supervisorof shipbuilding. Figure 1-1, view A, shows the number2647537 as an example under the NAVSHIP SYSTEMCOMMAND NO. block. 5. The revision letter was explained earlier in thechapter. It is shown under the REV block as A in figure1-1, view A.Figure 1-8, view B, shows the shipboard plannumbering system that was in use before the adoptionof the current system (view A). They two systems aresimilar with the major differences in the group numbersin the second block. We will explain the purpose of eachblock in the following paragraphs so you can comparethe numbers with those used in the current system. The first block contains the ship identificationnumber. The examples in views A and B are DLG 16and DD 880. Both refer to the lowest numbered shipto which the plan applies. The second block contains the group number. Inview A, it is a three-digit number 303 taken fromNAVSHIPS 0902-002-2000 and it identifies a lightingsystem plan. View B shows the group number systemFigure 1-8.Shipboard plan numbers. in use before adoption of the three-digit system. Thatsystem used S group numbers that identify theequipment or system concerned. The example numberS3801 identifies a ventilating system. To use thisnumber, relate it to the proper chapter of an NSTM. Replace the S with the 9 of an NSTM chapter numberand drop the last digit in the number. For example, thenumber S3801 would produce the number 9380, orchapter 9380 of the NSTM titled Ventilation andBlocks 3, 4, and 5 use the same information in theold and new systems. Block 3 shows the size of theplan, block 4 shows the system or file number, andblock 5 shows the version of the plan. FILING AND HANDLING BLUEPRINTSOn most ships, engineering logroom personnelfile and maintain plans. Tenders and repair ships maykeep plan files in the technical library or the microfilmlibrary. They are filed in cabinets in numericalsequence according to the three-digit or S groupnumber and the file number. When a plan is revised,the old one is removed and destroyed. The current planis filed in its place. The method of folding prints depends upon thetype and size of the filing cabinet and the location ofthe identifying marks on the prints. It is best to placeidentifying marks at the top of prints when you filethem vertically (upright), and at the bottom rightcorner when you file them flat. In some casesconstruction prints are stored in rolls. Blueprints are valuable permanent records. How-ever, if you expect to keep them as permanent records,you must handle them with care. Here are a few simplerules that will help. Keep them out of strong sunlight; they fade. Dont allow them to become wet or smudgedwith oil or grease. Those substances seldom dry outcompletely and the prints can become unreadable. Dont make pencil or crayon notations on a printwithout proper authority. If you are instructed to marka print, use a proper colored pencil and make themarkings a permanent part of the print. Yellow is a goodcolor to use on a print with a blue backgroundKeep prints stowed in their proper place. Youmay receive some that are not properly folded and youmust refold them correctly.