I have a heavy duty sewing machine and I was trained as a sailmaker but my training was with the Royal Naval Dockyard in Portsmouth so my trade is heavy canvas rather than sails. However I can repair some smaller sails - batten pockets and general tears for example. I've kept my palm and needle to hand so I can even hand sew some heavier points. I may also be able to help canal boat owners with covers and soft-furnishings... not professional but affordable!
I can of course also make or mend other boating kit such as screens and awnings so just ask and see it I can help.