Can I chase Canada geese on water in my boat?

This depends on whether the boat is under power or not. If an engine is being used, then this would be an offence under the Wildlife & Countryside Act 1981. Section 5 (e).

If the boat is being paddled by hand or powered by wind, then no offence would have taken place.

You can shoot geese from a stationary boat with an engine on but not in immediate pursuit.

https://www.legislation.gov.uk/ukpga/1981/69