I made that trip with Doc last October. We had multiple sharks everyday,
from the moment the cages were dropped until the moment they were hoisted.
We had sharks from 8 feet to 20 feet, though most of them were 12 to 14
feet.

On Horizon, the way Doc works it, you can have a number of camera setups
ready to go. You label each rig with "Gary 15" or "Gary 20" or "Gary 20-35"
and whenever you want to change you poke your head out of the cage, yell out
"Gary whatever" and they will retrieve the rig you desire. Having said that
though, I think a 20 is a better overall choice than the 15 **if you will
only have one camera setup** and the 20-35 is even better than that. I
wouldn't shoot any prime lens with a smaller perspective than 20mm though.
The sharks get close, we had a couple that were rather insistent on bumping
the cages, but most stayed 2 to 3 feet away on their close passes.

From the outside corner spots on the cages you can capture the whole animal
(plus sufficient background) as it approaches the bait lines with a 20. Also
when they come right up to the cage a 20 or 15 will work nicely. As they
swim under, around, away and whatever, you are still talking at least 20
before the water column deteriorates the image anyway.

It's a great trip, I hope to return again some day. Food onboard was
excellent, I mean really quite good. I'm not a drinker but was told the
concoctions were delicious. Accomodations are really bunkboat rather than
liveaboard, but for a 5 day cruise it hardly matters. There's lot's of
fishing to do in between your cage turns and the weather down there at that
time of year is really nice.

The sole downside to the trip was the crossing back to SD. Ours was as rough
as anything I have ever been on, far worse than my worse Coco crossing, and
lasted for a good 18 hours before the seas settled. Even if you don't get
sick you still cannot find anything to do to pass the time in the rollin'
rockin' Horizon....reading, chess, cards, they are all out of the question
because that little boat is pretty active in a heavy sea. So be prepared to
weather that crossing if indeed the seas do not cooperate on your tour.

I started the "dives" in a 5 mil with hooded 2 mil vest and eventually ended
up "diving" with just the 5 mil. The water is somewhat cold, but I
acclimated quickly and found more comfort in less neoprene. Some folks dove
dry, but I had been advised it wasn't necessary and found that to be true.

You probably will anyway, but just as a point of unsolicited advice: Pay
attention to their system for entering and exiting the cages, it works
nicely, is safe, and is the fastest way for the exchange from one group to
the next. We had one guy who thought he would do it his way and came *that*
close to losing his balance and falling off the cage into the water with 3
Great White just a few feet away. A 20 would have worked nicely for that
photo op as well! :^)

Have a great time. I am decidedly envious!