From Luang Prabang we took a boat upstream for a few kilometres then on to a tributary, the Nam Ou (River Ou).
The boat was a miniature of the Slow Boat, long, narrow, flat-bottomed, but seating about 12 people instead of c. 150.
This design seems ideal for handling the fast-running rivers with occasional shallow sections and rapids.
They’re not slow at all, merely slower than speedboats.
I was pleasantly surprised how stable they felt.