For kayak crabbing, there are essentially three types of traps from which to choose:
After experience with all three, I definitely recommend the ambush/conical style hoop net.
Weighing about 5lbs, they are half the weight of box traps, which makes a considerable difference on the kayak and schlepping them around. They stack nicely, which is important for attaching them to the kayak (I use 4 at a time). And critically, I believe they hold the crab better than the lie-flat hoop nets when pulling them up. (Watch this Dungie escape!)
The box trap is fine if you are going to drop your pots and let them soak for a number of hours. Just be prepared to haul around double the weight, and futz with popping them up, and last but not least, removing the crab is not as easy.
In my experience, hoop nets, and the ambush style in particular, allow for a considerably different approach to crabbing. You drop the first trap, paddle to the next location, drop the next trap etc. By the time you have dropped four pots, you can leisurely paddle back to the first pot and give it a pull. You really don’t need to soak the hoop net more than 15-20 minutes. Unlike the box trap, the crabs don’t need to find their way in through the door. (Yes, the conical trap is slightly more impeding than a lie-flat trap, but still very accessible for the Dungeness.)