Probably sand as well. Loosen the clamp screw, put the whole thing under water, push in as well as trying to pull it out.

I would try boiling water on the outside section only and somehow keep the inner section cold.. and you need a person at each end twisting rather than pulling..

This was and still is a common problem with two piece windsurfing masts.. and almost all adjustable paddles..

I once tried to twist one apart myself by putting the blade in a slot in the side of my house and twisting the end piece.. and all I did was twist the shaft out of the blade..

DavidJohn said..
I would try boiling water on the outside section only and somehow keep the inner section cold.. and you need a person at each end twisting rather than pulling..

This was and still is a common problem with two piece windsurfing masts.. and almost all adjustable paddles..

I once tried to twist one apart myself by putting the blade in a slot in the side of my house and twisting the end piece.. and all I did was twist the shaft out of the blade..

Lucky the side of your house didn't give way first