On Mon, 27 Oct 2008 21:17:19 -0500, Brian Whatcott
wrote:

I sampled price versus length from offers at SailboatTraderOnline,
for the names initialized by A thru G
(Allmand, Beneteau, Cal, Dufour, Endeavour,
Fountain, Grampian, Hunter)

..and planted the list of lengths versus boat bucks into NLREG
(a non linear regression tool.)

This came up with
Price in boat bucks = [ 0.115 times Length in feet ] cubed.

The fit is not particularly great (It explains 0.43 of the variance)
but it is plausible for a random sample of boats,
so for a
20 ft pay $12.2K
30 ft pay $41K
40 ft pay $97.3 K
50ft pay $190 K

Try it again based on price per pound and I'll bet that it is close to
a linear fit. New boat prices range from $20 to$30/lb and older used
boats anywhere from $2 to $5.