Friday, April 24, 2009

Fire Under the Sea

Aboard the USS Bonefish, 21 years ago today. Three men died that day.

Read here, here and here.


Anti-Air Warfare (AAW) Part 2

Part 1

This post will be about the Naval Tactical Data System, or NTDS.

NTDS as a concept is nearly 50 years old. The system transmits radar symbology among the ships in a task group. The original computers had a whopping 32Kb of core memory and they took up huge equipment spaces. They probably cost well over $500,000 in a day when an expensive new car cost $3,000.

In the `70s and `80s, the computers were replaced by AN/UYK-7s, computers that required air-conditioned spaces, water cooling of the equipment cabinets, special technicians to maintain them and were less capable than today's $500 desktop computer.

NTDS transmitted via radio (primarily UHF, I think) on three different data streams: Link 11, Link 14 and Link 4A.

NTDS enabled all ships in the task group to share contact and target data without voice comms.

Link 11 was a full two-way datalink. Link 11 ships both could originate the symbology and display it. The symbology was displayed on specially-equipped radar scope head. The symbols were a diamond shape (hostile), square (unknown) and circle (friendly). Full shapes were displayed for surface contacts, the upper half of the symbol was displayed for air contacts, the bottom half for subsurface contacts. Directional arrows were added, with varying lengths to give a graphic indication of speed. There was a numeric designation and additional data (course, speed, altitude or depth).

A Link 11 ship could be radar quiet, but because it was receiving Link 11 telemetry, all of this was displayed on the ship's NTDS scopes in CIC. The computers on each ship displayed things so that if no offset was selected, the display centered on the ship.

Aircraft carriers, cruisers, E-1/2s and long-range AAW shooters had Link 11 (CG-16/26, the few nuke cruisers, DDG-37s). Short-range AAW shooters (DDG-2s, FFG-1s) and ASW frigates generally had Link 14. Link 14 was not a computer link; the data was converted into teletype symbology. Sailors on Link 14 ships had to read the teletype data to other sailors standing behind transparent vertical plotting boards, just as they did in World War II. In a hot environment, Link 14 data was several minutes old by the time it was plotted and, for the purposes of AAW, it was all but useless.

Link 4A was a one-way datalink to older fighters, such as F-4s and F-8s. The symbology showed on their radar screens, enabling the controllers to designate targets to those aircraft without speaking over the voice link.

The F-14s' AWG-9 radar, while not capable of 360 degree coverage like the E-2, had a capability of detecting targets at long range. F-14s could and sometimes were used in a radar picket role; they were the first fighters equipped with Link 11.

Once things went really hot, then the voice comms came into use. That'll be the next topic in this series.

Thursday, April 16, 2009

Anti-Air Warfare (AAW)- Part 1

Defense of a task group is one of the newest warfare areas for naval forces. (Yes, I'm using the old term instead of the newer one "battle group". "Task" was good enough for Admirals Nimitz and Spruance, it's good enough for me.)

There are two guiding principles in AAW:

The first is "defense in depth." This means that there are multiple rings of defenses around the task group.

The second is "shoot the archer, not the arrow." If what the ships in a task group are doing is shooting at incoming missiles, then the defenses have already suffered a partial failure. The defensive ring around the task group should be far enough out to enable engaging (and killing) the missile-launching platforms. During the Cold War, killing the missile shooters spanned almost every area of warfare at sea: ASW to stop the cruise-missile submarines, anti-surface warfare (ASUW) to sink the missile carrying craft, which ranged from small patrol boats to large cruisers and even aircraft carriers.

Weapons and tactics are nice to talk about, but the most important thing is command, control and communications (C3). Without C3, the long-range weapons were useless. C3 in AAW was done by two lines of communication: the Naval Tactical Data System (NTDS) and voice radio.

Let's begin with look at the most important player in the AAW game: Airborne early warning radar. In the 1950s, the Navy used one airframe for ASW, AEW and for cargo-hauling, which was built by Grumman Iron Works. This is an E-1 Tracer. Tracers served the Navy for 20 years, until replaced by the E-2 Tracker. The Navy was very happy to get the E-1 and even happier to get the E-2, for retirement of the E-1 (as well as its sisters, the S-2 and the C-1) meant that the Navy also retired the use of aviation gasoline.

This is an E-2.

Airborne early-warning radar has two big advantages. First off, the detection range of an airborne radar is much further than that of a ship's radar, because the horizion is lot further away. Second, because the AEW radar is not overhead of the task group, detection and location of an AEW radar signal only tells the enemy that there is a task group somewhere out there, but it does not reveal the location.

But the information from the radar operators aboard the AEW aircraft has to be communicated, and that'll be the subject of an upcoming post.

Wednesday, April 1, 2009

The Ship's Store

Every ship had a ship's store and soda machines. The profits from those operations funded the Welfare and Recreation Fund. The ship's store was a counter-service operation on smaller ships and a walk-in store on larger ones. In the 1980s, cassette tapes, both blank and pre-recorded were big sellers. So was junk food, which the Navy called "geedunk," for reasons that nobody really knew. Personal service stuff, such as toothpaste, combs, shoe shine stuff, small uniform items (such as ship's ball caps and belt buckles) were among the items carried.

The biggest seller, back in the day, was cigarettes. When the ship was out in international waters, the sales were tax-free, and the cigarettes were known as "sea smokes". They were cheap. Really cheap. As in twenty-five cents a pack or two-fifty for a carton. Even in port, the sales were free of state taxes. Normally that was not a big deal for East Coast ships, as states such as South Carolina or Virginia did not have high state taxes on cigarettes.

Wise supply officers would overstock the ship's store prior to visits to some lesser-developed nations. Privileges to use the ship's store were extended to personnel at the local US embassy or consulate; they sometimes descended on the ship's store like a cloud of locusts. That made the supply officer and the XO very happy (the XO ran the Welfare & Rec committee), but it tended to piss off the ship's company.

A real fight sometimes ensued when ships were in overhaul. Shipyards all had canteens and/or "roach coaches"; cigarettes were a major part of their sales. Some ship's captains recognized that it was in their best interest to make it possible for the yard workers, known as "sand crabs" or "yard birds", to be able to buy sodas from the machines as well as smokes and geedunk from the ships' stores. First off, it reduced the time that the yardbirds took on breaks, so more work was done. Second, it really boosted the profits to the Welfare & Rec Fund. Some ships put soda vending machines right next to the Quarterdeck so all of the yard birds would know where the machines were.

That pissed off the canteen operators, especially in the Northern shipyards. They had to charge state tobacco taxes, so their cigarette sales took a serious beating. At least one shipyard complained to the local state tobacco authorities, who, knowing they did not have jurisdiction over Navy commissioned warships, referred the matter to the Naval Investigative Service (NIS). The NIS would send an agent or two to try and "talk sense" into the Commanding Officer and ask that sales of cigarettes and geedunk be restricted to ship's company only.

Many COs complied. More than a few, though, asked the "well, what if I don't" question. The answer was that if the civilian cops found a yard bird with a pack of untaxed cigarettes, they could arrest him, but there was nothing that could be done to the CO. The COs then would agree to only sell one pack of smokes at a time to the yard birds and that was the end of the matter.