Gamer's Notes for 6:54 to 6:59 PM - The Deaths of Dreadnoughts
At 9,800 yards, the German 12/50 had a fair to good chance of getting through KGV turret armor, per jj. The shell/armor/range/bearing combination combined to yield a die spread of 0 -116. The higher the die roll, the greater the damage.
The RN BBs, unlike the RN BCs, had very little GT risk from shock or minor penetrations of the turret/barbette armor. The above is reflected in jj by replacing certain probability ranges in the mid-90s with just large fires within the penetrated turret. Centurion, in fact, took just such a hit in the opening minutes ---but no GT.
The KGV and Orion turret armor is rated by jj to require greater than 105 to yield any chance at all of GT from a turret hit. The shell, not just splinters or fragments must get through the armor, because they are BBs not BCs, for any GT risk. In general, that means ranges lower than something like 10,500 yards for German 11/50 and 12,500 for the 12/50.
It takes a turret hit above 110 to put the RN BBs at GT risk from a turret hit, that is, to put the risk above 1 %. The probability spread for Ajax facing 12/50 fire from 9,800 yards put her at about a 5% risk from each turret hit.
The GT roll on Ajax was 113. Kblammo!
The die roll on Conquerer may be harder for some to accept, but I'll try to explain what happened. The jj model shifts the probability from mostly hull and deck hits to mostly superstructure and upper works hits as the range drops. Under 12,000 yards, there will not be many hits placed in those first two bins. Those that do hit the hull at low range have greatly enhanced chance of causing large flooding damage and even destroying power and propulsion machinery. (In fact, two Konigs have taken such bad flooding hits already. Historically, Invincible's hits on Lutzow were in this category.) The few deck hits have chances of hitting a barbette. Here, however, jj splits risk by design of target --- more in a moment.
For wing turret ships, hull hits also have a chance to hit a barbette, putting the Helgolands and Nassaus at somewhat greater risks than otherwise. On all center?line ships, barbette hits are lower threats, probability-wise, if they are on the first barbette and even lower if on last barbette, since less barbette is exposed above other compartments that could decap or otherwise disturb an incoming shell.
Thus, jj postulates greater risk if the hit is on a midships or superfiring turret. This is mainly due to the barbette being more "accessible" to direct hits. The GT hit on Conquerer was on the second turret. If it had been on the first or last, there'd've been risk of turret loss, but no GT (the die roll required would've been higher than possible). The die roll spread for the actual hit at just under 11,500 yards was 0 - 107. To get the GT, the die had to be greater than 105 - so the risk was just under 2% even after the hit was placed in the low probability bin. The roll was 106.
To recap (excuse the pun!), the shell had to hit (fairly low probability) had to be placed in the Deck bin (low probability) and then had to get a 106 or 107 out of a spread of 0 - 107. It did.
The loss of Centurion was not a GT. I left the characters in doubt, but it was a damage control failure that did her in.
In jj, a large fire near magazines, including secondary mags, begins to accrue explosion risks if damage control efforts fail. There is zero risk if the fire is fairly small, a tiny amount if the fire is moderate, and a small amount if the fire is large. However, the risk is a continuous one and only is mitigated if there are firefighters and damage control teams actively fighting the blaze. Any speed above 6 knots adds some extra risk and a little more above about 15 knots, and a little more above 24 knots. The PC version of jj had the increase as a smooth curve, but manually I do it by those discrete speeds.
On Ajax, there was a risk spike for such an explosion earlier. The phone going dead amid reports from the XO to the bridge on the progress of the fire fighting was due to a shell that slaughtered almost all on one side of the fire. Ajax survived that risk, in part, because initiative rolls let others quickly resume damage control efforts.
In the jj, the above initiative check depends a lot on ship-wide casualties (a simplification). That is, if the ship has taken a lot of casualties, the crew is presumed to be spread thinner, as back up personnel take over tasks of those lost. Also, there is a "shell shock" loss of initiative if the ship has been pounded with huge loss of life.
Centurion lost her fight for life. The last observed hit on the barbette/turret did hurt her, but was not the cause of death. She'd taken significant casualties and the hits had included several in the area of the fire-causing hit and in areas just aft. Far from coping with the flames, Centurion was losing the fire fighting battle. The hit from Ostfriesland took out most of the second DC team, after the first essentially disappeared to a man from the hit earlier that itself caused new visible fires just aft of the ones already out of control.
Since Konig was the LOB leader, that made the range greater to her than to Centurion for the opportunistic shooters further back in the LOBs. Second, though Konig took a lot of hits, casualties to the firefighters has been low, so far. While they have not beaten the fire, the fire is of much lower risk to the ship (in jj) with the teams on station to hose, flood, etc any higher risk spaces that might be threatened.
As for relative GT risks, the Konigs have the thickest turret/barbette armor in the battle. They also have no wing turrets. Since this battle pre-dates the post-Jutland RN ordnance improvements, the RN die spreads are lower. When, at the lowest range, Ajax was getting hit with a spread of 0 - 116, Konig was getting hit with a spread of 0 - 106. After the Jutland improvements, I think the Konig spread would be 0 - 115 for the 13.5" at this range (not sure, that's close, though) despite the better armor.
The 15" would be higher still. Even at the Baron's Jutland, the
spread would be something like 0 - 120 for that ordnance at this range.
The QE is still mercifully beyond visibility.
by Jim
To the Related Jutland Story at 6:44