USB memory stick where anyone can add files, but only I can read, modify or delete.

I.e. a stick where adding a file is equivalent to encrypting the file with my public key and mailing it to me.

PFD for Vacuum Flask

I want my thermos to float when I lose it from a kayak. So it needs a Personal Floating Device. Most likely solution is a neoprene cover. That would also reduce the noise when it's rolling around in an otherwise empty cargo compartment.

Kayak bottles

I want a bottle that will stay in place under the shock cords on a kayak's foredeck.

That most likely means one concave side to align with ridge running the length of the deck.

(And I want them both for cold and hot drinks.)