Submarine is a TSS → TSD → PC opener developed by Eternalaws and Not Kaiyon, given the name "Submarine" due to it's shape roughly resembling a Submarine diverging into water. This opener can be performed with an early L/J in the first bag. This opener leaves a relatively clean and easy to downstack board state thanks to multiple donation methods in the second bag.
ZLO Variant
Z→S, L→O→J
PC Chance 91.51%
L J Variant
J→Z, L→O
PC Chance 93.33%
If you have a late I and/or receive garbage when going for PC you can opt for a TSS into Tetris.
OJ Variant
O→J, Z→LS/L→SZ
PC Chance 94.52%
JZL Variant
J→Z→L
PC Chance 99.25%
OL Variant
O→L
Second TSD
J→S
The third bag TSD variant is only dependent on a J before S thanks to multiple helpful L spins.
PC Chance 40%
SZ Non PC Variant
This pattern has a very high succession rate thanks to multiple alt formations.
Possible Followups
J→S/Z, L→O
L→S→Z, O→J