In order to deal with that, RHS evolved over time a system which standardized ALL ASW weapons
(ship type as well as aircraft delivered) and which addresses the problem of different pressure
hull thicknesses re how that impacts damage from weapons. What we used was the design standard
for Hedgehog - which was itself based on the standard hull thickness of German Type VII and Type
IX submarines (which was 3/4 of an inch). We rated ALL ASW weapons in terms of their ability to
penetrate as well as ALL submarines were given "armor" = 1/3 of pressure hull thickness (it isn't
armor plate but it has some protection value). This was done in terms of the area in which a
weapon detonation has a 50% plus chance of rupturing the hull. That area is a function of the
individual weapon effective area TIMES the number of weapons in the pattern. This in turn was
reduced to a per cent chance. It turns out that the worst patterns in game terms are two very
small depth charges - these have values of 1. [A pair of JAAD Type 2 DC has a value of 1; a pair
of JAAF Type 3 DC has a value of 2; Four JAAF Type 4 DC - also a typical pattern - has a value of 4;
a pair of JAAF Type 1 DC has a value of 1 as well. Two US Mark 41 ASW bombs have a value of 3.]
Typical mid war patterns of 12 IJN ship dropped DC have values of 12. A pattern of 14 USN Mark 6
DC have a value of 42. Typical early mixed DC patterns of six Mark 6 and 7 Mark 1 have a value of 4.
RN patterns well illustrate the range of values: 5 "Minol" type are worth 8, 10 are worth 15,
14 are worth 21 and 26 are worth 40. Normally only ONE attack is possible for a ship or aircraft per
pass - except if there is an ahead throwing weapon as well as a DC pattern - in which case two
attacks are possible. ASW attacks "bearing" is always "all sides" - they are centered on a "datum point"
where the sub is estimated to be - but the sub may have sped up, slowed down or turned during the time
the weapons drop - so the attack tries to cover all possible positions at depth. The combination of
standardized weapons and standardized hulls and a limited number of attacks per pass results in a system
very like reality: subs are hit fairly often, but almost always succumb only to repeated hits over time -
unless a catastrophic event occurs. Aircraft and various types of ships have a different chance of detection
as well. We have to hope the code values for these are realistic - we cannot change them. But the results
after about three years of testing is pleasing - so they likely are ball park.
ORIGINAL: Barb
Game uses bombs as regular ASW weapon... i.e. just consider them to be air-dropped DCs...
IRL planes were sent on general search equipped either with
- regular GP bombs, usually instantaneous or very short delay fuse (which exploded upon impact) - for use against surface targets (like cargo ships, barges, light combatants, surfaced subs)
- Depth charges with shallow settings (in war changed from 100 feet to 25 feet) - which can be used not only for diving submarines, but put close against hull of the ship can do considerable damage too...
Wiki on operational research:Other work by the CC-ORS indicated that on average if the trigger depth of aerial-delivered depth charges (DCs) were changed from 100 feet to 25 feet, the kill ratios would go up. The reason was that if a U-boat saw an aircraft only shortly before it arrived over the target then at 100 feet the charges would do no damage (because the U-boat wouldn't have had time to descend as far as 100 feet), and if it saw the aircraft a long way from the target it had time to alter course under water so the chances of it being within the 20-foot kill zone of the charges was small. It was more efficient to attack those submarines close to the surface when the targets' locations were better known than to attempt their destruction at greater depths when their positions could only be guessed. Before the change of settings from 100 feet to 25 feet, 1% of submerged U-boats were sunk and 14% damaged. After the change, 7% were sunk and 11% damaged. (If submarines were caught on the surface, even if attacked shortly after submerging, the numbers rose to 11% sunk and 15% damaged). Blackett observed "there can be few cases where such a great operational gain had been obtained by such a small and simple change of tactics".
