The killer Whale Vehicle Addon is a vehicle that can be used to travel both in the surface and underwater.I'm still working in this add-on so sorry if there are some bugs in this add-on.
To get this vehicle in survival you'll need to craft it in the crafting table with iron blocks and glass, as shown bellow.... You need to interact or just click dive on the screen to use this underwater, and same to make it float.while on underwater look up to make the vehicle go upward.