Seriously considered one a good while back but :
Did not point well
Had concern over quality/content of bilge keel fill ( looked like steel swarf in the example I saw)
Good accomodation for O/A length
Flexing of hull evident when lifted into cradle
Wide beam to length ratio meant she liked to be sailed upright
Good value for money (length/volumn) per £
I've sailed a Cobra 750 fin keel extensively and found it to be a great little boat, surprisingly fast for its size and with excellent accommodation. Does tend to be slowed down or stopped easily bashing to windward in a steep sea, and I suspect the bilge keeled version would be worse for this.
She always felt solid, so surprised re. the flexing remark.
The Cobra would be, either a 700, 23', a 750, 25' or an 850, 28'. not an 820.
All David Feltham designed, moulded by Cobramould in the late 70's and early 80's. Almost all home completed, so will vary enormously. Sailed slow but steady, hulls generally well built, all had very high freeboard, if you are buying a twin keel one with aview to drying out, you may like to know that they all dry out with the nose down in the mud, for some reason, and not upright. This is in my experience of the ones that I have known, they may not all be like this.