Slight digression......No royalties David when you are employed to design anything....it took Cannon (the manuacturers), nearly 20 years to be brave enough to launch the design, it was so different to other bottles on the market.....and yes, it is still a WORLD best seller!!
Back to the water bottle.....I have had a look at pictures of St. Rocco, and I think you are absolutely right Ivo...and thinking about it realistically, the water could be easily sucked out from the narrow neck, and yet if the bottle were tipped over, it wouldn't spill the contents. Have you tried filling it with water to see if it bobs back upright if knocked over? You can see I am a very practical nurse, can't you!!?