I owned an Aquarius 7.0
which was the 1979 (only) version of the A23. It had a transom-mounted rudder on a long pintle (so you could pull it up) instead of the balanced rudder mounted in a 'cassette' in the cockpit sole, and a masthead rig instead of the common fractional. They all had the same steel swing keel, AFAIK.
At the time, Coastal Rec. made 4 product lines: Aquarius (21 and 23), Balboa (20 and 26, plus a 27 at some point, and maybe a couple more), Ensinada (flush deck, 20 ft I think), and the La Paz motor sailer. The whole company became Balboa, I believe, in or around 1980, and the A21 and A23 became B21/23. I don't know the rest and will accept that posited in a previous post. I'm not 100% confident in the models I gave anyway.
You can get critical replacement parts from IdaSailer, including a stainless centerboard, cables, rudder, even a CB winch rebuild kit - the original CB winch was a nifty bronze unit, and they're sought after by many owners.
I have lots of pics of mine on it's original trailer (and yes, it's trailerable - single-axle on the east coast, dual-axle on the west coast). I can email them if you want, but don't have a way to host them for linking to.
As I recall, the boat was initially a bit tender, but very stiff beyond that point. Sales literature showed them pulling the mast and sails under water, then letting it go and the boat righting itself, all with the CB up. It was marketed as a safe family trailer sailer, with easy to unstep mast for transport (I could do it myself). Some say it sails like a brick, but I know folks who own them, and with the right sails for the conditions get hull speed or better routinely.
It had a draft of only 13" with the CB and rudder up, with a skiff keel (with lead in it), and was designed to be beached. If had mine in all kinds of places you wouldn't take a keel boat, and at worst, I could hop into the water and just shove it back. Down side of mine is that the rudder was a single slab, and not kick-up, but if I kept it, I would have had Joel at IdaSailor make me a kick-up. The CB, of course, will swing up if grounded.
I only paid about $3k or so for mine, with original trailer with surge brakes, plus an original Evinrude 9.9. It was in superclean condition, except for the blown out sails, but was ready to go. Mine had a Merriman/Yacht Specialties added (not a factory option), which I removed when I thought I couldn't get a new push-pull cable (oddball size, but Edson stocks them).
I only let it go when I got a larger boat, but if I was going to get another trailer boat, I'd consider the A23. Lots of cockpit space, huge cabin for it's size, easy to sail, and pretty bullet proof.
If you want pics, let me know.