For those not playing the game. "Orel Cruising" is a term commonly used for running submarine fleets at World 2 map 3 (2-3 for short). With only 3 submarines you can complete the map without losing fuel, as you pass through 1 or 2 nodes that awards you fuel and refuel/repair consumes very little.
The thing is from all submarines available into the game, I-401 is the only one that consumes twice the fuel as any other even in her unremodel form. So it's very common for admirals not using her while doing their dailies (beat 5 bosses in any map at world 2, sinking transport ships, light carriers, etc.) or gaining fuel.
