Undiscovered Abyss

Round 48, with Deep Waters 1.4.0:

• Mobs swim instead of walking underwater: every body type has its own swim stroke, humanoids lie flat while swimming and tread water when still, and idle swimmers hover off the seabed. Crabs, scorpions and mantises still walk the floor.
• Safety pods: sailing into a water dimension with a Sea Chart drops you inside a floating safety pod on the surface. It is reused on your next trip, and the chart works from inside it to sail home.