You live on your boat, dress like a pirate and spend most of your time high as a kite.
You need to get your boat out of the water to repair some damage. That costs munny, so you go to Plan B.
YOu take your boat into an unattended lock, fill the lock up and then secure your boat firmly to the lock. You drain the lock to turn it into a temporary makeshift dry dock.

What can possibly go wrong?
Well, the weight of the suspended boat might cause the lock wall to collapse, filling your boat and the lock with rubble and cutting the Trent off from most of the canal and river network in the north of the country, possibly for months, and leaving people stranded all over the country.
