Extra fenders. A better anchor than what comes in that starter kit. A shore spike. Hot Sauce (a fast boat detailer and spot preventative by Boat Bling).
If this is your first Yamaha, it would be my suggestion, that you go out the first time, with your wife or significant first mate, and practice with the boat getting on and off the trailer, and docking, maneuvering around a buoy, etc. Do this on a weekday without weekend traffic at the ramp. Yamahas are extremely maneuverable but they are just different than other boats, even other jet boats. The posts on here I hate to read, are the ones that mention that first ding in the boat. It will happen as all boats get rash. But a little practice can prevent a gouge or someone getting hurt. The 242 is a big heavy boat and it doesn't maneuver like other boats or even like a jet ski. So practice the first time or two, without the big group or the kids. Now if the kids are going to be crew members, then no harm in them coming if they know this is a training run and not a day at the lake. No harm in combining the two, but get in some practice at the ramp and dock before you have to come back to a busier ramp and do it under pressure.
The rest of the stuff you need for storage or supplies with come as you see what you need. If you have had a boat, you know most of that. I can't tell from your profile if you had a seadoo before or maybe it was just a possible as you shopped. Figuring out what you need will be based on what you do with your boat and how you guys like to boat. If you raft up, bigger fenders, if you beach, shore spike, if you want to beach with the boat on the beach, keel guard. It will take time for you to learn the boat and establish your own way of using it. And you will love the boat! Here is a checklist I designed for my first Yamaha. It is something that you can use even with the 242. It was created in word and you can alter it to fit your own needs. Congrats and enjoy! And welcome to the forum!
