I work at Louisville assembly plant where the Explorer's are made, we own a 2002 with 4.6 and have the towing package. The truck will pull the boat power wise, but the transmission and rear end are the weak link's, with the independent rear suspension you lose alot of the towing capacity and with a boat that size you feel every little bump and hole you hit. My wife has pulled her 2 horse trailer with it a couple of time's, but prefer's to do it with my 1/2 truck, she say's it feel's more stable around curves and under braking even with the electric brake's on the horse trailer.
hope this help's, I don't want to trash the explorer's, but there just not much for pulling a heavy load.
Kydog