The first ones are going to be the:
what to do when you crash the boat rockgardening at night in a uninhabited island?
Well, we use duck tape and diferent types and sizes of flotation bags.
Before going for rockgardening or surfing betwen rocks, we inflate all this bags so if the watertight areas of the boat are broken in the ride, the amount of water you board is much less. The kayak will be still maneuverable and doesn´t go with the deities of the depths forever and ever......
We prefer several small bags instead of one big one. They can be adapted easly and there is no problem if one of them is punctured with the fibers.
A paddle float inflatable can be a good flotation device too but...
we like so much the small and very cheap bags to carry wine that you can see in the picture below.