Seat height can make a big difference. Lowering your seat will add stability. Even a 1/2" will make a difference. 2 3/4" above the keel is a long way. Adding more keel will not help the stability and might make it worse.

: I just finished my skin over stick frame kayak. I built it per the plans in
: "Wood and Canvas Kayak Building" by George Putz. I followed the
: plan for the 17 foot Southwest Greenland model. The only difference I
: reduced the length to 15' 9". The kayak is either really tippy or I
: don't know how to handle it. It is only the second Kayak I have ever been
: in. The other was a rented double sea kayak. I think my seet elevation may
: be too high. It is 2 3/4 inches from the top surface of the seat to the
: inside surface of the keel. My keel on the bottom is only 1/2 inches high.
: Does anyone have any comments before I start trying to lower the seat or
: add more keel? Thanks everyone/ Ken