breaking the Aleutian paddle

The Aleutian paddle is a pleasure to use, its comfortable, light weight and has a very nice grip on the water. It feels powerful too.
I have made 3 up to now and all of them have broken in the surf. the first one a couple of years ago while I was playing in the waves with Eli. You can see the moment of fracture in the video at 052--056. I guess there was too much pressure on the blade from coming down so hard.
So I made another and kept it our of the surf, just used it to paddle in flat water, until one day I heard the awful crack and found myself with another broken paddle. I tried to repair it with glue and screws and tape , but its still bust.

Top is the first paddle after attempted repair and it just broke again, bottom is the second paddle also attempted repair

Today I broke number 3, I have been using it for a while now and kept out of the surf

, but there were some cute waves just calling out to be surfed and off I went. As I applied power to the blade I heard that dreadful crack again and if you look at the top photo, you can see the middle paddle with a nasty crack right through the shoulder and into the loom.

So, how do I determine the problem? is it bad wood or is there something wrong with the design, maybe these paddles are not made for rough water.
Anybody got any good ideas.
The next repair will be with a carbon fiber sleeve which I have just received, but I would like to make an unbreakable paddle instead.