Trojan Transport for AIP Submarines

Recent Announcement: Ultramodern Diesel Submarine To Be Tested In Russia
"The submarine is notable for its high combat capacities, fair speed and cruising range. Saint Petersburg is able to stay underwater without refueling for 45 days." For export, not under ice.

Cutaway of Amur sub in transport-tender Zephyr al Yemini (a juicy target). The transport vessel features an interior docking well for AIP-sized subs and provides a disguised helipad.

Saint Petersburg's Nominals
Endurance: 45 days
Speed (submerged): 27.6 knot (sprint est.); 6.3 knot stealth
Crew complement: 35
Max depth: 984 feet
Propulsion: AIP oxygen-hydrogen fuel cells
Screws: 1
Submerged displacement: (est.) 3400 tons
Armament: Six tubes; 18 torpedoes / cruise missiles
Length 220 ft
Beam 23 ft
Draft 21+ ft

Pros
Quiet
Reduced Crew

Unannounced and Hypothetical
Manning (no haitability or relief issues)
Transportability yields time on station of up to 39 full days at unlimited range
Repairs, relief crew, stores, fuel and munitions eliminate return to port except for extraordinary maintenance or refitting (multiple transport-tenders required).

This arrangement would be no match for U.S. AIP submarines serviced by nuclear submarine mother ships (former SSBNs). - Hypothetical, of course.