How About a Coast Guard Sink-Ex?

Test firing of the 57mm Bofors aboard USCGC Bertholf, photo by MMagaro

Test firing of the 57mm Bofors aboard USCGC Bertholf, photo by MMagaro

Are our weapons adequate for the Ports, Waterways, and Coastal Security Mission? Let’s find out.

The Navy Times is reporting that the Navy will have an unusually large number of ships available for “Sink-Ex” exercises in 2017.

The SINKEX fleet grew from five ships last year to seven ships available in 2017, including four frigates, the landing ship tank Racine and two attack cargo ships.

According to the source document, the Navy’s 30 year shipbuilding plan (pp 13/14), one of the stated purposes of a Sink-EX is weapons effectiveness evaluation. I think this might be a good opportunity for us to test out our weapons for the Ports, Waterways, and Coastal Security (PWCS) mission. This mission implies we must have the ability to forcibly stop a ship, regardless of its size. A Sink-Ex could be an opportunity to answer once and for all the question “Is the Coast Guard adequately armed for the mission?”  Personally I don’t think so, and what little evidence we have seems to indicate that is the case.

The two attack cargo ships are Charleston class LKAs, the ex-Durham (LKA-114) and ex-St. Louis (LKA-116), built in the late ’60s. These are medium sized auxiliary ships, 9,000 tons light and 18,500 tons fully loaded, 576 feet (176 meters) in length. Structurally they are not much different from merchant ships of the period. Unfortunately they don’t have the big diesel engines found on modern merchant ships, and the are far smaller than many current merchant ships but they are still, in most respects, representative of the target set the Coast Guard should be interested in.

USS_Charleston_(LKA-113)

Photo: USS Charleston (LKA-113)

We have four gun systems that might be tested. .50 cal., 25 mm, 57 mm, and 76 mm. The 25 mm and 57 mm are particularly important as the .50 cal is probably too small and short ranged and the 76 mm is going out of service. Still, we should still attempt to include the 76 mm because if the 57 mm proves inadequate, our next question should be, “Would the 76 mm have been successful?” Testing the 25, 57, and 76 mm guns would require use of at least two ships, a 378 for both the 76 and 25 mm, and a Bertholf class for the 57 mm. (Alternately an LCS might provide the 57 mm, a Bear class the 76 mm, and a 110 or Webber class the 25 mm.)

1280px-USCG_Gallatin_Mk_75_firing

This could be a CG R&D project, but of course it would require Navy assistance, perhaps a joint project. Because our objective is to at least stop the target, rather than sink it, loss of power or steering would constitute a success. To determine if this is the case, we need information about what is happening inside the hull when the we get a hit. Will the round penetrate not only the hull but also critical systems, the loss of which would result in loss of power or control of the ship? Because it would probably be dangerous to go back on board the target after it has been shelled, the target would need to be instrumented with sensors and the results broadcast back. Aside from putting cameras inside the spaces, a technique might be to seal up and pressurize equipment like boilers, turbines, and steering gear and have them instrumented to detect any loss of pressure that would indicate a breach.

We would also want to conduct the exercise at a reasonable ranges. Since the real targets might be equipped with weapons that might be typically available to terrorist organizations, including anti-tank missiles and Soviet era antitank and anti-aircraft guns,that might target critical systems on the cutter, I believe the cutter should stand off at least 4000 yards, but for the 25 mm, we would probably need to close to 3,000 yards. A logical sequence might be,

  1. 378 closes to 3000 yards engages with 25 mm then withdraws
  2. NSC closes to 4,000 yards and engages, then withdraws
  3. 378 closes to 4,000 yards and engages.

We would also want to fire a reasonable number of rounds, probably about 150 rounds of 25 mm, about 100 rounds of 57 mm, and about 80 rounds of 76 mm, basically shoot enough to exhaust the ammunition normally carried on the mount.

Realistically this would have to be part of a larger Sink-Ex with more than one target, but it might be reasonable to allow the Coast Guard a day to try their systems against one of the targets before the other firing units come on scene.

Should our current systems prove not up to the task, we would also want to know the results for possible candidate systems, so we might ask that these candidate systems be used against the target as well. These might include, APKWS, Griffin, Hellfire, the 5″ gun, and the light weight torpedo. I don’t think it has ever been tried, but with the right depth settings, is it possible to hit a deep draft surface target with our current light weight torpedoes?

Let’s at least find out if we have a chance of succeeding in this mission. 

3 thoughts on “How About a Coast Guard Sink-Ex?

    • I was a bit disappointed to see that they left the torpedo tubes, Mk75 gun, and Mk92 fire control system and ALQ-32 ESM system antenas on board to be sunk with the ship.

  1. As far as instrumenting the hull to assess the results, it could also be an opportunity to expand the envelope of the CG’s use of UAVs. The Polar Star operated a ScanEagle earlier this year (a UAV that is becoming ubiquitous across the world) but as a fixed wing type, it might be difficult to accurately assess the damage in a flyby (although it would be interesting to try). Perhaps the USN and USCG could revisit the FireScout tests they carried out from a cutter a few years ago? Or, better yet, trial a newer and smaller drone that could potentially gain access to the ship’s interior. Having such a capability would increase the CG’s unmanned intelligence gathering options. Imagine if the first USCG presence on board a vessel, or in the wheelhouse, was a small surveillance drone, perhaps fitted with a two-way communication for talking to the crew, and launched in advance of the boarding party’s arrival? Your Sink-Ex idea could also trial this.

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