thanks for your thoughtful response. yes, i'm coming from an Allied perspective.
AirSearch to spot convoy routes & increase the detection level of targets would of course be useful, when available.
A CVL w/ a DB sqn (& tank range of 10) would have to be a carefully-planned op - getting the boats into position 1st, then high-speeding the CVL into position for (at best) 2-3 days of look-see before it ran low on fuel, missions & drop-tanks is a nift' idea! the initial moves of the boats would give some idea of the presence of enemy NavSearch, b/c it'd be key to have the CVL group arrive undetected. useful to put the skeer on an opponent in a specific situation, but not something you'd want to be doing repetitiously in the same area, w/o an unlimited supply of replacement CVLs!
also it's a complex hands-on one-off op, & i'm more towards looking for sub-ops in 'set it & forget it' mode. the 1-hex max reaction range of sub TFs is a key constraint.
i've used the 'patrol around target' option, imo it's better-used against coast-line targets than island targets, 'cos it favors the 'towards friendly' hexes. against islands, i prefer to lurk my boats on the 'towards enemy' side. also, 'patrol target' keeps the boats close-in, & i prefer a manual patrol-zone where one of the three hexes is offshore by 1 day's run, in order to shake off enemy aerial detection.
i'll offer this variant - say my 4 subs are 'led' by a 1-sub TF w/ an assigned patrol zone, the other 3 are in 1-sub TFs set to 1-, 2- & 3-hex 'follow' ranges of the lead sub. let's call this a 'trawl-net'. the lead sub is set to spend 1 day at each of its 3 assigned pat-zone hexes, this is my standard assignment to reduce fuel consumption and increase time-on-station. all 4 single-sub TFs are set to 1-hex reaction range.
my question is this - if the last boat in the train becomes adjacent to an enemy TF, will it 'react' to that enemy TF and attempt an attack, or will its 'follow' setting require it to maintain the specified distance from its leader (which will move to its next-specified pat-zone hex), & ignore the possible intercept?
Hmn, the way you propse to use the CVL is not the only tactical approach.
You could run the sub TF, whose cruise speed might be very similar to the CVL TF (particularly if you are using the Long Island), as the moving vanguard of a TG, operating within the naval search envelope provided by the air search planes. This would minimise the use of high speed fuel consumption. An alternative is to replace the CVL TF with a small surface TF containing a/some cruisers with float planes.
As to the specific question raise about the last sub in the train. I can't give you an anwser from experience because I don't give my TFs with follow on command a reaction range. However, on a close reading of the manual and my recollection of other relevant comments made by the developers, this is my take on the matter.
The follow on command is a destination order. Just as valid a destination as if you had given it the explicit order to go to the destination x/y co-ordinates. In moving towards their destination hex, the difference between the two inputs is that a TF with a follow on command;
"...During movement, it will always move so as to stay in the same hex as the TF it is unless ordered to trail at a distance. If the following TF is not fast enough to keep up, the followed Task Force will slow down to allow the following TF to keep up." (s.184.108.40.206 of the manual)
This attention to maintaining movement integrity is absent from TFs setting off from the same base and moving to a commonly shared destination (also see s.220.127.116.11.3 of the manual).
My take, and it is subject to correction from the developers, is that a TF's "follow on" command overrides the reaction order given to the follow on TFs. This would be consistent with a TF given the "meet TF" (and either merge or trail) order. It would defeat the purpose of the exercise to give a "meet TF" destination order if the meeting never occurs because the TF coming to meet has gone off somewhere else on a reaction of its own.
A further consideration which gives me some comfort that I am on the right track is that any TF with a "do not retire" order will not subsequently react whilst it remains on station. Reaction orders are very much intended to only become active for TFs on "patrol", although to muddy the waters submarines can launch an attack during the movement phase of moving towards their destination (ssee s.18.104.22.168 of the manual).
So taking the preceding into account this is what I think would be the most likely outcome.
1. The leading sub TF, which has a specified destination, which happens to be a patrol zone however you have structured it, will steadily move towards its destination, bearing in mind that on ocassion it might have to slow down to allow any "stragglers" to catch up.
2. The leading sub TF, given a reaction range of 1, might react to a target of opportunity on route to its destination.
3. The three sub TFs with a "follow on" destination will always attempt to be in the same hex as the leading TF. This objective will override any reaction ranges they themselves may have.
4. If the leading sub TF does react, then in accordance with (3) above the follow on TFs will attempt to move to the same reacting hex.
Hope that helps. Of course it would be better if a developer could give you a definitive answer. Nonetheless I think you are troubling yourself over a fairly minor matter. For what really matters is how the TFs perform once they arrive at the patrol zone, almost by definition they will have far fewer targets of opportunity getting to the patrol zone than they will have once they are at the patrol zone. Once there, they should not have the follow on command for that would tend to minimise one of the major advantages of having the multiple TFs rather than a single wolfpack, viz greater sighting odds.