Submarine retreat

@Krieghund
Scenario
At the start of the US turn there are 4 US subs in sz 97 and one Italian dd (deployed the previous italian turn).

US attacks the sea zone with 1 ftr and Italy scrambles 3 ftrs to defend.

4 subs score one hit , US ftr misses and so italians lose the dd.
Defending dd and ftrs score 2 hits and so US loses 2 subs

At beginning of round 2 there are
2 US subs, 1 US ftr and 3 italian ftrs

Rulebook
The attacker (never the defender) can retreat during this
step. Move all attacking land and sea units in that combat
that are on the battle strip to a single adjacent friendly
space from which at least 1 of the attacking land or sea
units moved. In the case of sea units, that space must
have been friendly at the start of the turn. All such units
must retreat together to the same territory or sea zone,
regardless of where they came from.

Seems there is no legal space for the subs to retreat to. There is no adjacent sea zone where at least one of the sea units moved. So does that mean they are not allowed to retreat the subs since there is no legal space for them to retreat?

In that case, if the attacker chooses to retreat, then can he just retreat units that are allowed to retreat (the air in this case) and leave the subs to continue the battle (where they would just submerge since there is no dd present).

@colt45554 submerging is not retreating.

I am trying to confirm that in this case the subs have no legal retreat. And so when the attacker decides to retreat at end of round 1, only the air retreats and subs have to stick around. In this case the subs would then submerge at beginning of round 2.

@ksmckay

there are variants to this case as well where the subs wouldnt be able to submerge (say the dd doesnt get killed) and trying to make sure that the attacker can still retreat the units that are legally able to retreat.

95% certain I am interpreting things correctly. But its a bit of a unique situation. Not too many cases where non amphibious units dont have a retreat path.

@panther

Its not a partial retreat. Its retreating all units legally able to retreat. Same as an amphibious assault.

@Panther Not saying you are wrong, but I dont think the rules are explicit in this case which is why I am asking.

In amphibious assault it doesnt say there are special rules for retreating different from normal combat. It says seaborne units cant retreat.

In the hypothetical situation I proposed, there is no path for the subs to retreat so you could and I do say that the subs cant retreat.

So in amphibious battle, units legally able to retreat do so, and I am asking for a sea battle, if units that have a legal retreat path can do so.

I think its a fair question without an obvious answer and two reasonable interpretations of the rules.

@krieghund thanks!