My first LOB was the Belize Aggressor 3 (BA3), and I learned a lot on that trip.
First, what to pack, get out the clothes that you want to take on the trip. Then put half of them away. Take a good look at what is left, and put half of those away. Wear some comfortable but relatively nice clothes (like a golf shirt for instance) on the flights and to have available if you want to go out Friday night to a nice restaurant in Belize City, but you will not need anything fancy on board the boat. Plan on a couple pairs of shorts and a few t-shirts. I tend to wear gym shorts because they are comfortable, but the big thing is that you will want to have something dry, so having more than one pair is important (or at least advisable). Also make sure that you have a few swimsuits so that you can rinse them out and have a dry swimsuit when you really want it.
You asked about a "typical day". The boat's motto is "Eat, Sleep & Dive" and IIRC, pretty much every day was a variation on this:
- Wake up
- Have breakfast
- 1st Dive
- Snack
- 2nd Dive
- Lunch (move boat)
- Maybe a quick nap
- 3rd Dive
- Snack
- 4th Dive
- Dinner
- Night Dive
- I seem to remember that on the Monday night there was no night dive to give as much time as possible to off-gas because Tuesday morning was the Great Blue Hole. Even if you are diving NITROX, this will be on air because of the depth. After this dive, you can either do a 2nd shallow dive or a tour of a bird sanctuary with Blue Footed Boobies. I opted for the shallow second dive and actually found the reef that forms the atoll surrounding the GBH more interesting & a better dive than the GBH itself. Tuesday afternoon it is back to your "regularly scheduled program".
Friday, diving will end after the 2nd dive and the boat will head back to Belize City where you can just chill on the deck or go for a tour. The big thing is that the crew will be busy "turning the boat" for the next group and it is best to stay out of their way. This will be the one time when you will not be their priority.
As for iPads etc. I am a photographer, but for the most part, I don't tend to edit my shots while I am on vacation. I do, however take an iPad Mini with me because that is what I use to log my dives. I might upload a few shots that I want to get a better look at than the LCD on the back of my camera can give me, but I personally would rather hang out with everybody than bury my face in an iPad or Laptop while I am on vacation.
One thing to keep in mind is that on a LOB, there is
much less room, so no matter how sociable the group is, be aware of and respect peoples' personal space and their privacy to an even greater extent than on a shore based trip.
Since this is you first LOB, a couple other things to keep in mind are that for most people, 5 dives a day is a lot. Both heat loss and exhaustion tend to be cumulative. If you do plan on doing 5 (or maybe more) dives every day, then bring proper thermal protection (a thick enough wetsuit) and take every chance you get to have a nap. Don't be afraid to sit out a few dives, after all, you are on vacation. Relax.
One last thing. No matter what else. Stay safe & have fun!