15/06/1997 01:00:00 - [United Kingdom] <BODY><P class=MsoNormal style="MARGIN: 0cm 0cm 8pt"><SPAN style="mso-fareast-language: EN-AU"><FONT face=Calibri>Up until this point we’ve been hunting comparatively easy surface ships in our lessons. Surface ships are constrained to one depth (the surface), and are inherently very noisy compared to submarines. Submarines on the other hand are able to change depth to make themselves more difficult to detect, as well as being much quieter than surface ships. <?xml:namespace prefix = "o" ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 8pt"><SPAN style="mso-fareast-language: EN-AU"><FONT face=Calibri>You’ll notice that the Trafalgar has a very long sonar sensor range, with&nbsp;two convergence zones covered by the radius. Open the Trafalgar’s database entry and look at the sensors section. Here we can see the Trafalgar is equipped with a Type 2065 Towed Array, which will be doing most of the heavy lifting as we search for our target submarine. Be aware that unlike the Basic Submarine Operations (1-4) series, you will now be presented with randomised biological and false contacts, meaning you will need to clearly identify contacts to be sure of their identity.</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 8pt"><SPAN style="mso-fareast-language: EN-AU"><FONT face=Calibri>While in previous lessons we’ve chiefly relied on bow sonar, ESM or off-board targeting to detect our targets, when hunting submarines in open ocean a towed array allows not only extra range to detect targets at long distances, but also allows us to search above and below the layer at the same time.<o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 8pt"><SPAN style="mso-fareast-language: EN-AU"><FONT face=Calibri>With a bow sonar, we are constrained to searching in the thermal layer the submarine is in; i.e. if we’re above the layer we will be searching above the layer, and if we’re below the layer we will be searching below the layer. Submarines equipped with a towed array that are at shallow or periscope depth use their towed arrays above the layer, and those that are at ‘just under the layer’ or ‘as deep as possible’ use their towed arrays below the layer. However, submarines at ‘just over the layer’ trail their towed arrays beneath the layer, while their bow sonar remains above the layer. An additional benefit of this tactic is that while our submarine is above the layer, it is very difficult for another submarine below the layer to counter-detect us. This tactic however requires<o:p></o:p></FONT></SPAN></P><SPAN style='FONT-SIZE: 11pt; FONT-FAMILY: "Calibri",sans-serif; LINE-HEIGHT: 107%; mso-fareast-language: EN-AU; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: "Times New Roman"; mso-bidi-theme-font: minor-bidi; mso-ansi-language: EN-AU; mso-bidi-language: AR-SA'>With this in mind, let’s get to finding our target. Plot a course to the north-east, set your speed to creep and your depth to ‘just&nbsp;below the layer’.</SPAN></BODY>

15/06/1997 01:01:11 - [United Kingdom] New contact! Designated GOBLIN #1 - Detected by S 107 Trafalgar  [Sensors: Type 2065 [Type 2076 Suite]] at 7deg - Estimated 65nm

15/06/1997 01:01:11 - [United Kingdom] <BODY scroll=auto><P class=MsoNormal style="MARGIN: 0cm 0cm 8pt"><FONT face=Calibri>Contact! We’ve detected an underwater sonar contact. As you can see it is a convergence zone contact. You will recall from tutorial 1.1 that a convergence zone contact can be in any of the shaded green rings displayed surrounding the <I style="mso-bidi-font-style: normal">Trafalgar</I> but not between them.<?xml:namespace prefix = "o" ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 8pt"><FONT face=Calibri>It is natural to want to change heading towards the contact, however this will <I style="mso-bidi-font-style: normal">reduce</I> the amount of time that you hold the contact because as you close with the contact the amount of time it remains in the convergence zone decreases. In CMO as with real life, the longer a passive sonar contact is held the more data can be gained from it. <o:p></o:p></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 8pt"><FONT face=Calibri>To maximise contact time, set your heading to put the contact at either our 3 or 9 o’clock, i.e. 90 degrees off our port or starboard bow, and maintain a speed set to creep.&nbsp;Our intention is to identify the contact, and if necessary obtain a course and speed so we can move to intercept.</FONT><o:p></o:p></P></BODY>

15/06/1997 01:01:26 - [United Kingdom] Contact: GOBLIN #1 has been type-classified as: SSN (Classification by: S 107 Trafalgar [Sensor: Type 2065 [Type 2076 Suite]] at Estimated 65 nm)

15/06/1997 01:02:11 - [United Kingdom] Contact: SSN #1 has been classified as: Type 091 Han - Determined as: Hostile (Classification by: S 107 Trafalgar [Sensor: Type 2065 [Type 2076 Suite]] at Estimated 59 nm)

15/06/1997 01:02:11 - [United Kingdom] <BODY scroll=auto><FONT face=Calibri>
<P class=MsoNormal style="MARGIN: 0cm 0cm 8pt">We’ve identified a contact of interest, it’s a Chinese Han class SSN—a notoriously noisy boat. But, without spending all of your time reading books about submarines, how will you know which boats are noisy and which are quiet? In CMANO, the answer is the database.<?xml:namespace prefix = "o" ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 8pt">Open the database entry for the Han by clicking the contact, then clicking the hyperlink style blue text ‘Type 091 Han’ in the right side bar. Here we can find a veritable treasure trove of information about our target. To get a sense of how noisy the Han is, check the ‘Signatures’ section of its database entry, and then compare this with the Trafalgar. As you can see, the dB levels of noise emitted from the Han are much higher (e.g. Han VLF passive sonar noise is 140dB while Trafalgar VLF passive sonar noise is 100dB; the difference between a&nbsp;jet engine at take-off and a hand drill respectively).</P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 8pt">The noise level of submarines varies according to design and technology, but for reference an 'Average' submarine in the late 90's when this tutorial is set would have a VLF signature of about 120dB, making the Trafalgar a particularly quiet boat and the Han a particularly noisy one. You can get a 'feel' for this by browsing database values of platforms from a comparable era.</P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 8pt">Now we’re going to close with the Han. The simplest way to accomplish this is to hold the Han CZ contact for as long as possible by maintaining a heading to keep the CZ contact bearing 90 degrees to port or starboard of our submarine. Then, when contact is lost (indicated by a timer appearing below the contact and the growth of the uncertainty zone), immediately plot a course directly towards the contact to a point just short of the first convergence zone and set speed to full or flank. Once you have arrived at the designated position (in this case 24nm—the distance of the first CZ), return to creep speed while keeping the same heading&nbsp;and wait to re-acquire the target. Re-acquiring the target after these sprints can take several hours. Be patient and use time compression!<o:p></o:p></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 8pt">Repeat this technique until you are able to obtain a direct-path contact. Once you have a direct path contact, manoeuvre into the Han’s baffles and close to a range of 4nm. Aim to remain above the layer to reduce the chance of being counter-detected.</FONT></P></BODY>

15/06/1997 01:02:34 - Switched side to: United Kingdom

15/06/1997 01:05:56 - [United Kingdom] Contact: Type 091 Han #1 has been positively identified as: Type 091 Han - Determined as: Hostile (ID by: S 107 Trafalgar [Sensor: Type 2065 [Type 2076 Suite]] at Estimated 77 nm)

