Andrew:

I would sugest that if you can take your gear to a friend who has a vacume seal like a food saver or the equiliant. Take your gear that you know you will use only incase of an emergencey and seal it up with an extra ziplock back in it. This way your can save space and ensure total waterproofness of the gear in the vacume sealed bag.

The extra ziplock bag is for when you open the vacum bag you have another bag to put the gear in.

While I know you won't have the K-Bar in the watter, or rather I should say it in't your intention, I would sugest going with a more watter aprpriate knife as I know watter is a tricky item and can work it's way into the darndest places.

Finaly I would sugest a phylosophy that I see repeated here a lot, "Two is one, and one is none." Meaning that redundancy is your friend.