I do not have direct experience with diving off of a sit-in kayak, but it doesn't seem like the right way to go. I have a pair of sit-on-top Ocean Kayak Scupper Pro TWs, they are great little vessels, and well-suited for diving off of. The well in the stern is the perfect size for an AL80 / HP100 plus a scuba rig. I've only done it a few times though -- the most recent time was last Summer, and, my main dive buddy had
a really bad experience, so we haven't made it out there since. But I'd like to get out on them again, if you're ever the Monterey area, let me know.
FYI, there is a small vessel / kayak
subforum on ScubaBoard, you'll find a lot of information there from people with much more experience than I have. But that being said, here's a few things I have learned, I hope it helps:
- I like to have several 3-4 foot lengths of shock cord. On one side, I tie a boltsnap to it, on the other side, either a second boltsnap or just a bowline knot. These are invaluable for keeping your gear attached to the boat. I have a few of these pre-attached to the kayak, and a few more assembled and stowed in an easy-to-reach storage compartment. Clip off every single piece of gear, all of the time. One for your mask, one for each of your fins, one for your paddle, one for your lunch bag, etc.
- Assemble your scuba rig ahead of time, bungee it to the kayak ready-to-dive, with the BCD full. Pack the rest of your gear with the stuff you want first on the top: don you fins first, then mask, then weight belt, then gloves and hood, then splash in and put your scuba rig on in-water.
- When you return to your kayak, some gear is easier to doff in-water: mask/gloves/hood/belt, clipping them off one at a time. Getting your scuba gear back into the boat is the hardest part, and there are two ways: either shove it up into the boat from in the water (easier with fins on), or first climb up on top and then haul it in behind you (easier with fins off). If you're hauling it behind you, a buddy can help from in the water, but be careful -- if the boat flips, both you and the scuba rig will be headed in their direction.
- Do not use a drysuit. While paddling out, you will have a tendency to overheat, which will encourage you to open the zip, or peel the suit halfway down. Once you do that, flipping the boat goes from a nuisance to a dangerous situation: the suit will instantly become completely flooded, provide no buoyancy or cold protection, and will create a lot of drag while you try to swim / re-mount the boat. So if it's too cold to dive wet that day, just leave the kayaks on your truck.
- Don't do apex dives off a kayak until you have some experience under your belt. The boat adds a lot of little things to worry about, so you don't want to already be task loaded by the dive itself.
- When you're with a buddy and you moor the boats, moor them facing each other (bow-to-bow). This will facilitate you and your buddy keeping an eye on each other while you gear up.
- Bring a DSMB for the dive, and launch it before you surface if you're in an area that has boat traffic. Which you probably are, since you took a boat there yourself.
- Bring (and use!) kayak safety gear -- PFDs, an effective bailing tool, a radio/PLB if you're going way out there.