Nice write up! I would say that you can most certainly cavitate when a torpedo is coming after you!
I couldn't help but notice you said the Kilo was in range of the Mark 48 at ~19 nmi when your torpedo has a max range of ~21 nmi. 21 nmi is the torpedo's maximum running range but that is not equivalent to your maximum engage range. If you assume the Kilo is going to run away, your maximum engage range is effectively a lot shorter than the torpedo's running range. Check out this video I made about it a long time ago:
Basically, for a Kilo, your maximum engage range is ~7.5 nmi (with Mark 48 at 55 knots and Kilo at 20 knots). This is the distance at which the Kilo can never outrun the torpedo (excluding maneuvering and countermeasures). However, this can probably be increased by a reasonable amount due to how RA has changed the TIW modeling of Dangerous Waters.
Unfortunately, the 688I is becoming outdated tech. 6 knots is likely to have caused you some trouble. A Seawolf or a Virginia can run around at 6 knots+ easily but with the 688I, I would stay around 3-4 knots.
Where is this mission located? It sounds fun
Cavitate as a reaction on a TIW though? This mission has me thinking, before you drop all stops and ring the flank bell, you should make sure you can see the torps on at least the narrowband towed (and make sure it isn't showing up on any arrays with a smaller range). The reason I say this is because you might get a TIW from an airdrop that is off by 5+ NMs and then you just give away your position with a knee-jerk cavitation run. Just me thinking outloud here after reading your response. Maybe an airdrop of 5+ NM error is a little too optimistic :P
Good point on the difference between max range and engage range, I'll take a look at the video. Also thought I'd comment, maybe if I'd ran the torp at low speed it would've had enough fuel by the time it enabled to catch it? Because he wouldn't have heard it till it was much closer to him....I think.
How has RA changed the TIW? I know not of what you speak! But I am interested!
You think 6kts is too noisey?! Even at ranges between 10 to 15 NMs? Wow. Didn't think that. I hate creeping along at 3kts because it takes ages to make turns and you gotta wait even longer for the towed. Just adds time to getting rid of ambiguous contacts and changing from lead/lag courses. Even the 688I huh...Dang...I like that boat
The mission is in the Persian Gulf. I DLed it from Subguru DW Scenarios, its by Wargamer Scott.