I'm having difficulty googling what a "rescue rocket" is. I keep finding info on a video game and safety during space travel. What does "rocket" mean in a 1800s context?

I found this: https://museum.maritimearchaeologytrust.org/2025/05/29/rocke...

Is it a gunpowder rocket used to push a boat through the water instead of using rowing oars?

Is it just a gun that sends the carrying cable, what makes it different from any other gunpowder gun? https://www.britishpathe.com/asset/52937/

I wonder if it's for firing lines over to a shipwrecked vessel, to assist with getting people ashore.