Ocean Troop Transport

The Ocean Troop Transport (OTT), also known as the S-TRN', was a submersible transport used by the Trade Federation to transport B1 battle droids over and under water.

Characteristics
The OTT had a slow top speed and often had a bad habit of sinking. It performed more reliably as an aquatic surface repulsorcraft. Two versions of the craft existed, one armed[2] and one unarmed.[1] The armed version was described as a battleship.