did ya read this thread?
http://forums.iboats.com/showthread.php?t=304353
while i've not done the deed. someone else here, can't remember who, did. from memory, since i can't find the thread. he cut large holes under the carpet to get at the wet foam. said he used a spade, a crow bar a large long drill bit to help loosen it up. scooped it out and replaced it.. basically any tool ya can use to loosen it and scoop it out with it sounds like to me.
good luck.