Signalman 1 & C - Historic Naval Ships Association

Figure 13-22.—Modern submarine.on the hull, and bow profile. The visual codingapproach is based on examining the profileappearance of a given submarine and assigningnumerical values that best correspond with illustratedexamples appearing in selected appearance groupcoding. Three factors are usually sufficient to identifya class; thus each submarine class has a three-digitnumber. In cases where several submarines possessthe same appearance code number, their profile andphotographs should be carefully compared todistinguish between them.General Appearance CodingSurface submarines and partially submergedsubmarines are best identified by their sailconfiguration; hence, the sail shape is the mostimportant factor in coding the general appearance ofsubmarines. (See fig. 13-23.)Sail Placement CodingThe system for coding the sail placement parallelsand reinforces the system outlined under GeneralAppearance Coding. Generally, the sails of newersubmarines are placed closer to the bow than those ofolder designs. In examining the five basic sailpositions (fig. 13-24), you should choose the examplethat best shows the position of the sighted sail inrelation to the hull. Using this system, you should bewithin two or three silhouettes in confirmation ofsubmarine class and type.Bow Profile CodingBow profiles (fig. 13-25) are assigned numericalvalues in an ascending order that coincides with theseverity of the angle at which the stem or deck lineapproaches the waterline. On the newer submarines,the bulbous bow is seldom seen; when the submarineis surfaced, the deck line forward of the sail appearsto slope gently into the water. On the older submarinesthe bow has a definite terminal point, and the angle ofthe stem is either raked or sheer. Note that in thecoding of bow profiles, structures atop the bow are notconsidered as part of the bow shape. Bow shapes areoften difficult to see because of observation angle orwater wave action; but this should not constrain youfrom identifying a particular submarine based on thefirst two codes.General Recognition FactorsThe principal Soviet innovation is the streamlinedturtleback sail, which has a curved topline that mergeswith the after trailing edge of the sail. Forclassification, the new turtleback sail is assignedappearance group code 1. (See fig. 13-23.)Rectangular sails are so numerous that they mustbe broken down into subdivisions as to how theyappear in relation to other features. The new SSBNsusually have a rectangular sail with sail planes. Theyalso have a bullet-shape bow, a stern fin, and aprominently raised and broken deck line aft of the sail.The SSBN classes largely constitute appearance group2 (fig. 13-25).13-16