I paddle a Speedster which is hard to keep upright sometimes. These
boats have a factory hatch between the legs. So I bought an extra
hatch cover, drilled it to pass the hydration tube through and now
put the bladder inside. So the Center of Gravity is lowest. It's so
good I sometimes use the full water just for the ballast effect.

I did the same for my old Valhalla, but it's more of a hassle due to
the Keelson down the middle.

By the way, I've got a new religion: use a paddle leash. I wound up
swimming after my wind-blown Speedster at the end of a short race.
No way could I catch the bugger.