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An array of tactile antennae/feelers?

now you’re thinking like a catfish! i like it

Entertaining the idea of a probe sticking out the front led to a realization. The problem is you're never going to stop in time if you're at speed. You need to know well in advance that something's there.

Perhaps a sound signal that's a copy of something naturally occurring, e.g. by sea animals.

That came to mind for me too.

Fleet of small scale autonomous drones? Bonus points if they're water soluble.