> Question for you as a sailor in a lighter boat. If alerted, would you be able to change direction fast enough?

That would depend. While under sail (i.e. 99% of the time during ocean crossings), no, not really -- not enough speed and limited heading change options in the prevailing wind. But this is balanced by the fact that, during a typical ocean crossing, I might see another vessel every 20 days or so.

Notwithstanding those facts, I ran my mast-head navigation light, all night, every night, because I was alone on the boat, therefore ... asleep for eight hours every night. If I hit something, it was likely to be something smaller than another boat. Like a waterlogged container or a sleeping whale, both rare but dramatic events.

> Also, I’m guessing at some point the collision is extremely dangerous for the boat not the whale.

Not normally. I've hit whales several times during my time as a sailor. I could tell it was a whale because the boat "thumped" the obstacle instead of loudly banging as with a floating log. I hated the thought of colliding with a whale and did all I could to avoid it, but after dark, such things can't be avoided.

In the case of a big vessel, it's all reversed -- the risk is to the whale, not the ship.