Now, in retrospect, I know that was the wrong decision - and indeed 'less than expert' on my own behalf. In addition to the above, there was a very strong wind blowing from the left. It was an inconvenience that was waiting to happen - and caused me a great deal of embarrassment, along with the possibility of a huge bill from a rescue service - e.g. £300!
I should have held a steady course up the middle of the channel - and certainly I will next time. Powered boats might have to give way to manually propelled boats but after causing me a massive problem there was not a word of apology from them. I wish I had sunk them both!
After 5 hours on the sandbank and two failed attempts at towing, another (more competently crewed) narrowboat named 'Dragonfly' persisted for long enough - at least an hour - to help me, and subsequently and consequently got stuck themselves. I felt very guilty about that of course. By then I was getting free, but a third boat came along and pulled the second one out before I had chance to go to their rescue.
I should mention that there was never any risk of injury, and the boat is unharmed. Only my pride is injured.
All I had on board to thank my rescuers was a cheap (but cold) bottle of white wine and some cans of beer, but they seemed to accept them quite willingly. It was the least that I could do in the circumstances.
5 hours on a sandbank and wading in water up to my waist wasn't entirely on the plan for the day!