I have been fishing out of a kayak for a while now. Nothing like catching a big fish in a little boat. My first yak was an 11 foot Ocean Kayak Caper. I needed a small yak I could put on top of a little car. It was fine for small ponds but it was as fast as a paddling a trash can lid if I had to cover water. I upgraded to and Ocean Kayak Prowler 15, which was a 15 foot yak. Much, much faster! I sold my Caper and kept the Prowler.
Here are some tips to buying a yak.
1: Don't worry about stability. You will outgrow a stable kayak in 2 days and want something faster.
2: Always buy a sit on top, forget the sit insides. Sit insides are dangerous. If you flip them, they are swamped and you are not getting back in. A sit on top you can climb in and out of in the water.
3: Read reviews and maybe test paddle some if you can.
4: Try and stick with the bigger name brand models....Ocean Kayak, Native, Malibu, Hobie, Wilderness Systems. They have been building quality products for a long time.
5: Use your yak a lot before you start rigging it up. Remember once you drill a hole in it......it will always have a hole in it .
6: Don't underestimate the power of a rudder. Being able to steer a yak with your feet is fantastic. You can now drift fish and steer your yak. It makes it much easier to paddle tight creeks as well.
I love talking yaks. A rigged up kayak is really fun to fish out of.
If you want to know how stable a sit on top kayak is. I sit sideways on mine when I fish, like sitting on a park bench. Both legs hanging in the water. And I stand up in it and push with a pole to sight fish for Reds at high tide. I have also had it anchored and climbed in and out of it in the water.