[mechanical_fish]

If you make the umbrella ribs more rigid you will tend to make them heavier. You could improve the leverage of the braces between the stem and the ribs by attaching the braces farther out on the ribs and lower down on the stem, but that will collide with the owner's head unless they hold the umbrella higher, which will cause more leakage and catch more wind and make it harder to brace the stem against your body in a wind.

I'd be very hesitant to claim that I could design a better umbrella. They've been evolving for a very long time. Maybe modern materials would help, but I for one wouldn't dare buy a carbon-fiber umbrella because I just know I'd leave it on a bus or something. Cheapness is a feature too.

Meanwhile, the hilarious invention at the link not only looks ridiculous, but I'd have to be convinced that it wouldn't drip all over my lower body. And how on earth do you carry it when it's folded up? A big feature of the standard umbrella design is that it's not that hard to carry or store while folded.

I have a nice waterproof hat from Outdoor Research and a Gore-Tex jacket. For serious swimming I've also got waterproof pants and even gaiters. That combination seems like it would be superior to the space helmet.