Captain Jack's Treasure!
Cap'n Jack 'as once again sailed 'is Black Pearl t' 'is favourite 'arbour - Pirate's Cove on De Courcy Isle. After downin' a bottle o' rum 'n staggerin' onshore, he port 'is most prized booty in a secr't location nr'by. Yer challenge - t' find Cap'n Jack's treasur' chest. T' numbers above will get you t' a dock. Count t' number o' sides on tis strange beastie and call it "A". Then, be usin' t' formulas below and ye should 'av 'er in no time. Go thar, its within a thousand or so paces as they say.
B = 4A + 8
C = 2A
49 05.B2
W123 43.C6
'Av Fun
The cache is not at the above co-ordinates but is within a 10 minute walk from the dock. The overall difficulty rating is based upon the fact that you must take a private boat to the island.