How accurate is this

[MAK]

Came across this site and curious on how accurate the information is;

soldboatprice.com

soldboatprice.com recently sold Hatteras
site lists 2 recent sales

53 Classic Motor Yacht asking $166,700 sold $75,000 date sold 5/3/18
56MY Motor Yacht asking $133,400 sold $65,000 date sold 4/27/18

both sold at about half the asking price, looked at other builders(Viking; Californian) on the site and a lot of the sales are also at drastic reductions. I understand that condition and circumstance has a lot to do with final close price, but if you description sure paints a different picture,

am fairly well versed in the classic car market, but new to the boat market, so the question
Is this the market?
Is this information accurate?
So what is a realistic offer against asking? Half? a third? ????