Hi Sean,

First off I'd like to say that for the most part what you forget at home someone will lend you. There are a lot of generous people in the sport who will do about anything to get you on the water. That said, here is more stuff to bring:

2 cycle oil
WD40
gear case oil
prop nuts
spark plugs
tools - screw drivers wrenches etc
knee pads or pad for boat
wet shoes
extra clothes
sunscreen
camera
video if you have it
GPS for recording speeds - or Keller speedometer
notebook to keep track of your set ups and results
stop watch - some guys like to have one in the boat so they can make timed runs at the clock before the race starts
sponge
drain plugs
starting fluid - for drying out engine
small plastic bucket
soap/hand cleaner
waders - if the water is cold
extra starter ropes - depending on the engine you run
shim sticks - 1/16", 1/8", 1/4"
height checker - make sure you are legal (can borrow)
angle checker - to check prop shaft angle (should have one since they are all slightly different
EZ canopy (nice to have)
legal gas - have yours checked before you mix with oil
paper towels
duct tape
extra kill switch tether
cordless drill & bits
food & drink
test wheel
holy cow, no wonder I need a bigger van

I'm sure there is more, maybe someone else could chime in.

Bill III