I own a 35 with my brother for 3 years now, we are doing a quite intensive refit.
Normally the boat has a shaft, i have seen a refit with a saildrive but this not common.
The deck is single skin. (see pics) However there are reinforcements with plywood.
For example at the anchor winch, which was in our case rotten. but not beyond repair. (epoxy!).
In 1987 the yard just cut outs holes where needed and did not laminated the sides of the cut outs. After 30 years this is sometimes a little problem.
when you buy a 1987 boat you have to prepare for a lot of work and investments.
at least this is our conclusion, but maybe we have a higher standard of perfection then average.
for the engine (2003T Volvo Penta 2000 hours )for example we:
-send the gearbox away for the ms2b spline issue
-overhauled the cylinder head incl. atomizers and atomizer copper sleeves
-renewed the starter and fuel primer pump , waterlock, ALL the hoses and turbo
-renewed the prop shaft, prop and shaft seal
-renewed the oil cooler for a non Volvo Bowman cooler (cheaper!)
-overhauled seawater pump and dynamo.
-overhauled the exhaust elbow (ceramic coating)
-cleaned the fuel tanks
This winter we are doing a overhaul of the anchor winch and the chain locker (leaking where the cables are going through the bulkhead.
And a complete overhaul of the steering system (seal sets for the hydraulics, rudder bearing and reinstall of the rudder trunk which was leaking)
Off course i don’t know in which condition the boat is where you are looking at.
but our experience is that a 1987 Nauticat is a lot more work and costs then we expected.
However to sail and live aboard a NC35 is good boat.
NC35 Silver Crest