Just broke my paddle by landing on the nose of my foilboard after breaching. The paddle shaft was in front of me when I connected. Snapped clean in half. I liked the paddle as it had an oval shaft & ribbing which was great for grip & & the paddle always aligned its blade to the water so that you wouldn't get that wasted paddle stroke that can occur with round shafts.
Lucky it lasted me about 5 years & made me think not to buy an expensive one as it only takes one accident to blow at least $300.
So have ordered one for $150. SUPCO brand. But no oval shaft.
Anyway I had repaired another paddle a few years ago that snapped close to the blade due to bad design. The blade shaft being too short snapped the main shaft during normal hard paddling.
I had a go at fixing it by cutting off the damaged end of the main shaft & using a piece of plastic plumbing water pipe that had a nice easy fit over the main shaft to use as a sleeve.
I then heated the end that fits over the blade shaft & rammed it on to take the shape & let it cool. I then removed it & slid it over the main shaft. Then glued the blade & main shaft back together & let it cure.
Then glued over the joint & slid the plastic sleeve over the joint & let the glue cure.
Hasn't failed me yet over 3 years.

Thanks Mark. I was already planning on fixing it myself by heat softening some plumbing pipe & inserting it as an inner sleeve. It will have to be lengthened of course so the sleeve will be made longer & I will make up the gap by binding layers of matting over the sleeve & will over lap the main shaft a bit.
But if the main shaft is damaged elsewhere, I will purchase another shaft & modify the blade shaft to fit. I can buy another handle easily.