d) Why does the value of boats fall off so fast? Some new boats seem
to loose half their value in five years.

Because people are stupid enough to buy a new boat which costs a lot
of money. Same as with cars.

Not all boats lose that much. In 1989, an Island Packet 31 listed at
under $78,000. Today there is a 1989 on Yacht World for $74,000 and this
is typical for IPs. Of course if you count inflation--
Still not bad for an 18 year old boat.
Gordon