[BLOCKING] Boats can't ride across descending ice smoothly

Summary:
When riding a boat across ice, the boat briefly comes to a stop every time you drop one block.

Impact:
This is the core mechanic for our free piece of content and ruins the speed and feel of the gameplay.

Repro steps:
1. Create a line of ice descending a few blocks.
2. Ride a boat across the ice.

Observed behavior:
Boat pauses on each drop.
Expected behavior:
Boat freely skids across drops.

Video: https://drive.google.com/a/noxcrew.com/uc?id=1kXY2QnxZIoAVpNv9Iq-c0spiPjFN-KxL