Kayak for fishing? Sit on or sit in?

SOT by all means and 12 feet as a bare minimum.

and my 'yak of preference is the Cobra "Fish N Dive" as the proud owner of one.

12' 6 ' long, exceptional stability with a 36 inch beam with a 600 pound capacity.

There are many things you should think about before purchasing a kayak. Some kayaks feel stable in calm water, but once the water get rough it isn't stable anymore. Some that may feel tippy are more stable in choppy water. The longer a kayak is the easier it is to keep straight when paddling a distance, but shorter boats are more maneuverable.

Also I recommend you check out other kayaks and not stuff that comes from the big box stores. Find a local kayak shop, they know much more about kayaks than the general sales clerk at bass pro. Local kayak shops also have demos where you can try before you buy. It is the only way you can really decide what is best for you. You should check out Wilderness Systems kayaks, Ocean Kayaks, Jackson Kayaks, Native Kayaks to name a few.

I have both a sit in and sit on top kayak for fishing, A Necky Vector 13 and Necky Manitou 130. The sit on top is better for storing gear on the back deck and easy access when you are on the water. However, both my kayaks were not made for fishing, but made for touring coastal waters. I bought them for their performance and they are multipurpose boats for me.

I have a 14 foot open cockpit two seater sit in that is a kit from Foldbot. It's wood frame and covered in tough vinal. Had it for 40 years now. You can't tip this thing. I would defiantly recommend a sit in.

Sit ins are my prefrence, you can store all your gear inside the kayak.

Sit on and the bigger the better. ; ) ~good luck catchin'.