There’s several ways of getting afloat after going aground without needing poles.

The simplest is to go slowly (I emphasise the word SLOWLY) backwards until you are free. If you go slowly, the propellor doesn’t suck you down.

Method two is to swing the stern in towards the shore with a hard, fast, sideways move of the tiller. As narrowboats turn about the middle, taking the stern towards the shore will often move the bow off the obstruction and into the centre of the channel. Then go SLOWLY forwards.