Sub Combat with Multiple Boxes

[NatRapsEno]

Can a player with surprise points and subs declare a sub combat, select the 0 box (which has convoys) and another box with enemy combat ships, use 3 points to select a target from the non-zero box ships, and then have the rest of the results apply to the convoy points automatically as normal?

[Courtenay]

Yes.

[Orm]

Indeed.

Might not even need to use surprise points to declare it a SUB combat.

[Joseignacio]

11.5.10 Submarine combat
Submarine combat allows you to attack enemy convoy points. Either side can also spend surprise points to pick a submarine combat even if there are no subs or convoy points included (see 11.5.7).
In a submarine combat, each side’s SUBs (not any other units) will fight the opposing side’s included non-SUB units. If each side has both SUBs and other targets, there will be 2 separate combats. For each submarine combat, add up the non-SUB side’s ASW factors:
 2 for each SCS included (CLiF option 75: each BB adds 0);
 1 for each CV included (CLiF option 75: each CV adds 0);
 1 for each air-to-sea factor included (including those on CVs that
aren’t damaged) during fine, rain or snow;
 1 for every 5 (SiF option 9: 2) US or Commonwealth convoy
points included in a combat in 1942;
 2 for every 5 (SiF option 9: 2) US or Commonwealth convoy
points included in a combat in 1943; and
 3 for every 5 (SiF option 9: 2) US or Commonwealth convoy
points included in a combat in 1944 or later.
The non-SUB side uses these factors to attack the SUBs. You do this in the same way as a surface naval combat except that you use the ASW row of the naval combat chart and only count the SUBs as targets.
The SUBs also attack in the same way as a surface naval combat except that they use the SUB row of the naval combat chart and only the convoy points count as ships (1 ship per 5 convoy points).
SiF option 9: Every 2 convoy points (and any spare point) counts as a ship.
If no convoy points are included (only possible if you spent surprise points to choose a submarine combat ~ see 11.5.7) then you fight on the ‘0’ ships row.
Losses inflicted by the non-SUB side can only be taken on the SUBs that attacked them (owners choice). For every 3 surprise points you spend, you can select the target SUB instead of the owner (see 11.5.6).
Losses inflicted by the SUB side can only be taken on convoys (unless someone spends 3 surprise points to inflict them on another target). If convoy points can take no further losses, ignore any remaining losses (unless you spend surprise points to select another target).