I was thinking of a new submersible transport craft that serves as a decent improvement over the Triton. The Poseidon is basically the Skystriker over the Skyranger, requiring some research, mainly Ion-Accelerators and Aqua Plastics to say the least. Like the Triton, it has no weaponry as it is strictly a troop transport. But the additional engine power and the aqua plastic airframe allow this transport to reach target sites quicker. Furthermore it features 2 exits instead of one, a large 2 space exit door in front (similar to the Triton) and a small 1 space exit door on the opposite side of the hull, close to the cockpit. This allows for more flexible troop deployment. This makes the Poseidon transport quite useful as a stopgap before the Leviathan.
Description for the Poseidon:
The Poseidon is a superior assault squad transporter, with a similar size, shape, and capacity to the Triton. The Aqua Plastics Airframe and the Ion Propulsion systems allows this craft to arrive at the target quickly.