RogerBW's Blog

Fourteenth Harpoon PBEM AAR: Black Buck One 04 December 2015

Another scenario from South Atlantic War, the Black Buck One raid on the airfield at Port Stanley.

There's not a great deal for either side to do in this one. The Argentinians set up their air defences; the British decide on an approach route. In both cases they went close to the historical pattern, with Argentine mobile radars on the hilltops, and the British coming in from north of east.

The Argentine guns and missiles were spread over the near-island where the airport is sited.

The Vulcan was spotted with about six minutes' warning, and released bombs while a few miles off-shore. (Incidentally, stats for the TPS-43 and TPS-44 radars are singularly lacking from South Atlantic War first edition; I don't know whether they were in an old Harpoon data annexe that I don't have. But they're in the second edition PDF from Wargamevault.)

The Tigercat launchers and long-range AAA guns were able to engage, but even with radar guidance their odds weren't good, and they didn't bring the Vulcan down.

The bombs hit, and I started to see why Harpoon has a reputation for being complicated. First of all there was the base chance of hitting the runway at all - a Medium target from Medium altitude with a Ballistic bombsight has a basic 3% chance to hit. You'd think you'd just roll 3% 21 times, but not. Bombs are divided into sticks of six, 21/6 rounds to 4, for +4 = 7% (because they're spaced out in a long line, the odds of getting a single hit go up, and the odds of multiple hits go down). Then we use the Stick Hit Table to determine that there's a 35% chance of one hit, 6% of two, 1% of three, and resolve the whole lot with a single die roll. Well, all right, but it seems like a lot of work to determine that, yes, one bomb hit the runway.

Then there's the question of scatter, for which the only guidance is for "30 or more bombs […] dropped in a single pass". 21 is nearly 30, so I used the rule from that (any target within 250 yards of the line of flight and 1nm along that line from the target is also attacked by a reduced number of bombs), but with a danger space of ⅔nm and 175 yards each way. Still, at least I could readily plot this to see what was in the footprint. I'll admit I'm really quite proud of this image.

This ended up being a 5% chance of hitting each grounded Pucará and a 14% chance of getting the airport buildings. One aircraft was hit, and so were the buildings.

So that's a Decisive British Victory: "Damage runway, ramps and airport buildings, while the Vulcan escapes." Though I can't help feeling that this ends up being a bit of an exercise in dice-rolling, without much opportunity for the players to make interesting decisions.

Thanks (and apologies) to John and Marco for playing this one.


  1. Posted by John Dallman at 11:40am on 04 December 2015

    For the British player, given he has to try to attack the runway and the airport buildings, he pretty much has to attack on the NE-SW line. Going south around the islands and coming in heading NE gives the opponent much more time to spot you.

    I briefly considered coming in from the NW and pretending to be a flight from Argentina, but I didn't have IFF or call signs for that, and it means you can only hit the west end of the runway if you also want to attack the buildings in a single pass. And multiple passes, and generally hanging around, seem like a really bad idea. The quick smash-and-grab, as the RAF did it, does seem like the best way.

  2. Posted by Ryan at 02:43pm on 04 December 2015

    Well done on the bomb damage zone image. Not really sure what else the players can really do in this one.

  3. Posted by Rory at 04:31pm on 04 December 2015

    Hmmm, so how do you calculate the release point and duration of the run for the purposes of the rapid bomber exfiltration?

  4. Posted by John Dallman at 12:23pm on 05 December 2015

    Roger's automated implementation of the Harpoon rules takes care of that. I picked course, speed (obviously maximum) and altitude band, and ordered the turns after release. That was it.

  5. Posted by RogerBW at 09:53am on 06 December 2015

    The only constraint on the bombing approach (level bombing ad Medium altitude) was "must fly straight from 5nm to 3nm from the target, and release at 3nm". My manoeuvre system has a "fly straight towards the target" command (actually it's the "intercept the target" command, but if the target isn't moving…)

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