You cannot sink someone else's end of the boat and still keep your own afloat.

We knew if we did fall through the ice, the boat would stay afloat and we could hang on to it.

The CAW, given the context, has done very well. The boat is afloat and upright after going through the rapids. They wanted to protect their members.

There is a ship afloat without a captain,

Sometimes you just have to pee in the sink.

As the station wagon pulled back onto the highway, the sun was slowly sinking below the horizon like a leaky boat. Well, except for that fact that boats are not generally round, orange and on fire. Hmm. Come to think of it, in no way whatsoever did the sun, in this instance, resemble a leaky boat. My apologies. That was a dreadful attempt at simile. Please allow me to try again.
As the station wagon pulled back onto the highway, the sun was slowly sinking below the horizon like a self-luminous, gaseous sphere comprised mainly of of hydrogen and helium.