Here is a robot dog that can withstand exposure to water and carry lots of load. The Unitree B1 Robot Dog has max walking load of 80kg. It is IP68 rated for protection against dust and water. This robot weighs 50kg. It lasts up to 4 hours on battery and can walk as fast as 1.8m/s.
This robot can overcome slopes up to 35 degrees and 20cm stairways. It uses Jetson Xavier and depth cameras to perceive its surroundings.