I'm in the same boat, so to speak. I'm 6'0 and 190, and I've built a Petrel. I'm new to this style of kayak...I finished it in late August. I don't know if you're an experienced paddler, but I'm told I'll feel more stable after I spend more time in my kayak. So it's me, not the kayak. 

Every time I go out, I feel unstable at first and then settle in. I'm told by my experienced paddler friends that I'll have that feeling for a couple more months. I've joined a group that paddle off the coast of Southern California most Sundays, and so I've been getting used to rougher waters. A few times, I've just paddled around marinas and I'm feeling more and more confident as I hit wakes and wind waves. I've yet to capsize unintentionlly, but I've had a few close calls. I'm learning to roll.

I've just finished yet another retrofit of my cockpit, this time to change the padding on the side of the cockpit and change how the back band is suspended.  I've seen some pretty neat custom back rest setups where people have built back supports using a combination of plywood and/or closed-cell foam. I'll try that if my latest back-band set up doesn't work. I've also read, however, that the back band is there to keep you from sliding around and not for support as it is in a sit-on-top. Not sure. Learning. I definitely need to lean back for rolling and whatever support I have has to fit in and under the spray skirt, so whatever setup I have needs to accomodate that.

Cheers

the Chesapeak series are relatively stable boats.  I started out with a chesapeak and at first felt unstable.  one thing I learned is that most of the time you want to let the boat roll with the waves.  Let your waist bend to keep your body upright over the boat but let the boat tip.  As long as your weight is over the boat it will not go anywhere.  A comfortable seat that is very low in the boat, hip pads that keep you from sliding around, pads under the deck where your knees meet the deck and a back band that gives you some support, and sitting upright, not leaning back all give you a better feel for the boat.  Having a paddle in the water also stabalizes things.  

then practice leaning the boat (you stay upright over the boat) by lifting one knee or the other and soon you will feel much more comfortable.

At least that was my experience.  I now paddle a Petrel which is a bit less stable but still easy to keep upright.

Ed

FITZ

 I have had a Chesapeake 17 for several years now. I am 6'3" 220lbs.  I have to agree with Ed the boat seems a little unstable at first, however once you settle in and get comfortable with it I think you will find it quite stable. The hip pads and deck pads are a must they will allow you to move the boat from your hips while keeping your body verticle.  I have found the best thing is to just relax and let the boat roll with the waves.

Have fun

andy 

I thought that I had made a huge mistake the first time that I paddled my 17LT. It felt like sitting still on a bicycle, trying to keep my balance. After a few paddling trips, I settled into the boat.

Then we went on a 6 day Everglades trip, loaded with gear, I could have paddle away from the group with ease. Only twice did I worry about my boat. One close encounter with a Dolphin, close enough that I don't know how he didn't hit my boat. Once, in the dreaded quartering seas and winds, easily remidied by a skirt. I was fully loaded, taking water over the stern. I have discovered that the 17LT is a very capable boat.

JRC

The Chesapeake 17 is a very stable kayak, IMO you should keep paddling and you will eventually get used to it. When I bought my first sea kayak after paddling a wide  plastic Rec kayak for several years I felt the same way. The first couple of times I took that thing out I was convinced that I had made a $2,000.00 mistake.

The reason that it feels unstable is because it is so alive and quick!  I built a Chesapeake 17 and an 18 over 10 years ago.  I fish in the ocean for Striped Bass from the 17 and I only weigh about 165 lbs.  I have yet to dump anything!  Just keep paddling for experience and heed the advice given above!  They are wonderful and beautiful boats!  Enjoy!

Thanks for the advice.  I will have more paddle time in the spring.   I love the boat but just need to get use to the fit.