It's often used metaphorically to mean getting ready for any tough situation, not just weather.

Metaphorical Use

This phrase is casual and might be used in daily conversations among friends or colleagues.

Informal Tone

Can be adapted to various situations, not constrained to any specific type of trouble or difficulty.

Originally, it was a command on ships to prepare for bad weather by sealing hatches with tarps.

This term refers to a specific action on board a ship to prevent water from getting inside.

It's technical jargon, so in nautical settings, the phrase has a clear, practical meaning.