Does speed does not effect ASW effectiveness?

[davidlondon]

Am I right that the speed of ASW vessel does not effect its effectiveness?

Example: a series of 1,100 ton vessels, Destroyers and Corvettes, built at he same time, hence with same technology; similar armament, except that the Corvettes can't carry torpedoes, one example without additional depth charges, others without:

35 knot, DD, NO addit'l DC, ASW value 6
35 knot, DD, additional DC, ASW value 7
30 knot, DD, additional DC, ASW value 7
25 knot, DD, additional DC, ASW value 7
20 knot, DD, additional DC, ASW value 7
15 knot, KT, additional DC, ASW value 7
10 knot, KT, additional DC, ASW value 7
05 knot, KT, additional DC, ASW value 7
01 knot, KT, additional DC, ASW value 7
00 knot, KT, not permitted

Interesting. While we can not build zero knot vessels we can go as low as one knot: they have the same ASW value, and appear to still be effective This seems counter intuitive. It makes me chuckle to call them sub chasers since they won't be chasing anything.

While I do not have references to hand I would bet pennies to pounds that in the real world speed matters. But the designers cannot model everything. And IDK they might already be working on something for the next release, or there is something in the black box already doing this - I don’t have the skills to find out.

My thought is some sort of effectiveness modifier against sub speed. Perhaps a figure that rises automatically over time, or against the enemy submarine tech. I'd imagine not a straight line relationship but a bell curve of some sort, perhaps with a ceiling somewhere.

So it looks like base ASW value for kit is:

500 tons - 3
600 tons - 4
900 tons - 5
1,100 tons - 6
1,400 tons - 6
Increased DC add +1
2 K guns - ?
4 K guns - ?

Plus other modifiers according to tech.

Finally, as an experiment I redeployed the one knot vessel from Northern Europe and it made it to the Mediterranean. I would have thought that it would have had trouble even getting out of port under its own steam. Drifting out on the tide perhaps?

[andrewm]

The need for speed for an escort varies a lot depending what you are escorting and what the subs can do. Escorts for CV and BB need to be fast as these ships cruise at relativly high speeds and they need to maneuver around them, on the other hand they are difficult to attack as they move faster than subs before the late 40's. The Flower class escort was reasonably effective but slow, the protected convoy's which were slower. They were too slow though as they had little if any speed advantage over a surfaced sub and if they stayed to prosecute a contact they took a long time to catch up with the convoy , faster sloops and converted DD were more effective but still slower than a fleet destroyer with speeds in the 24-28 knot range.
Streamlined subs and particularly nuclear subs need escorts at least that fast to be really effective so they can reposition to attack a defected sub, but in the same time frame the escorts started to aquire stand off weapons with Helicopters or rockets to launch torpedo's to the contact (Ikara, ASROC). Although as long as your escort can keep up with the merchant ships it is still useful as the enemy has to come to them

[wlbjork]

Base ASW is 1, plus 1 per 200 tonnes of weight and is capped at 5. Extended depth charge racks provide +1, as do pairs of K-guns. An ASW mortar provides +2.

We don't know how speed works in the ASW role. I haven't carried out any scientific study, but it seems to not play any noticeable role - that is, you lose more ships with slow ASW vessels or sink more subs with fast ASW vessels.



IRL, vessels travelling too fast - especially in he early days of Sonar - could overwhelm the system leaving themselves effectively blind and therefore vulnerable.

[gurudennis]

IRL, if a sub can outrun its pursuer when submerged, then such a pursuer is nearly worthless as an ASW vessel. A handicap in surface speed is less of an issue, up to a point.

As an example, a Type VII U-boat could make something on the order of 17 kts on the surface (just over 18 with extraordinary measures) and close to 8 kts submerged (closer to 4 kts sustained for any length of time). Conversely, many low-tonnage Allied escorts barely pushed 15 kts on a good day - but it worked because their surface firepower would force the sub to dive and deprive it of the speed advantage.

Before the invention of depth charges mid-WWI, the most common tactic was to ram subs, and that too requires speed.

I think the game should feature a steep penalty to ASW score for vessels slower than the expected submerged submarine speed for a given time period; and a further minor penalty for speed below that of a contemporary surfaced sub. If the value can't be dynamic, it's OK to tie it to submarine tech at the time when the escort is built. As a side effect, it will also cause ASW corvettes to eventually become technically obsolete, something that regrettably never happens in the game today.

[williammiller]

I'm not sure if ASW is modified 'after the fact' by ship speed, but Fredrik W would know for certain. If not, then this is a good idea to add.