I had an Alacrity - many years ago and thoroughly enjoyed it.
It sailed like a dinghy with a roof on it !! It was a Bilge keeler and still sailed well ... performing reasonably in the Club events.
The Alacrity was actually a version of the imported Catalina and was part of the early Jaguar development.
Points to look for : a) Rudder stock fixings are bolted through the stern and can lead to cracking and crazing of the gel-coat around the bolt holes. Easy to fix .... fill, fair and epoxy a backing pad inside the transom to take the limited load, b) the rudder stock was norammaly from laminated woods and tends to 'open' at the seams when sailing hard ... again can be repaired easily, c) Osmosis is most likely, but generally on these lay-ups where they were hand-laid and heavy ... will most likely be micro-blisters and to be honest not a threat to the boat ... mine had it for years, I'm a surveyor and never treated it !! Shame on me !, d) samson / forw'd mooring post is generally oak and passes down through deck to keel line. The forward internal bulkhead is often screwed to the face of it providing the anchor locker etc.... look for water ingress around the post underdeck as it rots the wood and can shear off.... general signs of deck working around the post on deck and absence of sealant will be good indicators, d) window leaks are common as the upper moulding is lighter and flexs more.
Set the mast forward raked to reduce weather helm ...
Otherwise its down to the normal basic detective work of gel-coat crazing etc. and overall form.
They are a strong boat, sail well and in the later version actually had 2 cabins .. mine was the earlier 3 berth single cabin job ....
Oh and by the way ... officially designated the Alacrity 19 .....
if you want to e-mail direct to me .... then no problem :
Oddly enough a day or so back I memntioned on this site that I once owned one of these boats.
It took me on an exciting 6 month trip back in 1975 to the Balieric Islands and back.
If you want I can give some more info via a PM Ive also got photos etc. but in brief these are good strong little boats with OK but unremarkable windward performance. We got caught by the " Tremontana" coming back from Menorca to Barcelona and weathered that for 36 hours (later heard that it had blown F9) and survived, although I wouldnt recomend it!!
I think there is a website run for the Vivacity owners which might include the Alacritys as they are very similar ( I think 20ft iso 18ft 6)