Reddit mentions of Bonine Motion Sickness Tablets-Raspberry-16 ct., Multicolor (27516)

Your certification is perfectly valid and welcome on dive boats provided the dive site falls inside your certification (ie, not too deep or technical, etc).

Some things to think about:

• Seasickness - Even if you don't normally get motion sick you might get seasick, it happens. Get some bonine before you go. Take it easy on breakfast and stay hydrated! If you are feeling seasick there are a few things you can do, get to a place with airflow, watch the horizon, of if possible lie down flat (preferably close to the boat centerline). You will usually feel better once you start your dive, so usually its worth it to do the second/third dive of the day. If you are using a wetsuit, it can make the feeling worse when wearing it fully zipped up on the boat, so try and minimize the time you have it fully zipped up if you are feeling seasick.
  
• Gear storage - unlike a shore dive, storage space is limited. I'd highly recommend a mesh bag something like this for example. It lets you transport all of your scuba related gear in something that takes a minimum of space. I'd also recommend a dry bag for things like your wallet, keys, cellphone (if not left in the car), dry clothes etc. There is dry space on the boat obviously but its at a premium usually (depends on boat size/configuration).
  
• Getting ready to dive/exiting the boat - Unlike on your shore dive where you likely gradually entered the water, you will go from boat to water very quickly. The boat crew should make an announcement to start gearing up, that is your signal to get into your wetsuit and be ready to go. A couple of key things, MAKE SURE YOUR AIR IS TURNED ON, make sure you removed the bungee cord or similar type of restraint from your tank/1st stage prior to getting into it so you can actually stand up when you are ready. You will exit the boat either via rolling off or via a giant stride (just depends on the boat/crew/etc). Don't be anyone in this video. Regardless of how you enter before you leave the boat.. mask on, reg in mouth, air into your BCD (nothing crazy, but not an empty BCD either), put a hand to your mask to help keep it in place, look in the water BEFORE you start the exit to make sure no other divers are there (tank to the head would SUCK). Give the boat crew the okay dive sign. Follow the DM's instruction on how they want you to descent/group on the surface/etc.
  
• Getting back on the boat - It all depends on how the boat is setup. There are little elevator setups, multiple different types of ladders, swim up platforms etc. What the crew wants you to do ahead of time should be explained very clearly. Personally if it is a fins off ladder, I ask if I can keep them on my wrists instead (through the fin straps) of handing them up, having had to do a swim with no fins it is no fun. Regardless of the platform, be very cautious of its rise/fall with the ocean. Once you are safely onboard, get out of the way of people just leaving, swap your gear over to the next tank as soon as you can. Keep drinking fluids to stay hydrated.
  
• dive briefings - hopefully the crew does this at a point when you aren't gearing up etc. But pay attention! This isn't the time to be screwing with your gear, trying to put something on, etc. Your only job at that moment is paying attention
  
• tank dust covers - Don't put them back on after you dive, they are normally used to distinguish full vs empty tanks.
  
• questions - If you have any questions what so ever ask them! Questions on dry land are better than questions on the boat, questions on the boat are better then questions in the water at the surface, and questions at the surface are better than questions underwater.

I'm surprised no one has mentioned Bonine

you forgot to get this
https://www.amazon.com/Bonine-Motion-Sickness-Tablets-Raspberry-16-ct/dp/B000YA8NYQ/ref=sr_1_3_a_it?ie=UTF8&qid=1478018236&sr=8-3&keywords=anti%2Bmotion%2Bsickness&th=1