Sewing - it's the most wonderfully mindful activity. Clothes, curtains/blinds etc for the boat. Lots of online fabric shops. There are also some beautiful narrowboat embroidery projects, eg
https://mariescrossstitch.co.uk/modern-narrow-boat-cross-stitch-kit-by-heritage/?sku=HCNBMN944A
https://mariescrossstitch.co.uk/canal-boat-tapestry-kit/?sku=BNT1950&gclid=Cj0KCQjw94WZBhDtARIsAKxWG--VjYP75D4qEensBNT_VZvF4beClhAB8JAF4I_VZ8cE99IMr2W7qs8aAik1EALw_wcB