The thing that im hung up on is that in order for the “Doesnt block enemy movement” rule to trigger, the condition of only transports or only subs respectively.  If either instance triggered it then the rule should state both transports and subs in the rule like “off shore bombardment” rule for battleships and cruisers. it states both units use the rule simultaniously and not exlusively.

Heres the scenario.

Allies have a US sub and an AUS transport in the phillipines in sea zone 35. and a US destroyer in sea zone 36.

Japan has a fleet of mixed ships in Sea zone 20 with the sea port in kwangtung.

The Japan player is wanting to get to the south pacific isles his next turn. sea zone 36 is blocked with a speedbump US destroyer. No question.

If sea zone 35 only had the US sub there then anything but a Japan destroyer could move over the sub ignoring combat. Any inclusion of a destroyers turns the sub into a speedbump. If the AUS transport was by itself any and all ships could ignore it and move past. But since the transport is no longer the ONLY enemy ship in the sea zone because it is accompanied by the sub it can not be ignored there because both ships become a speed bump.

Correct?

If not what in the rules am i missing?