Stereo Problem

I really do not know anything about stereos or wiring. We had the boat out this past weekend and everything was working fine. The stereo was cranking like it usually does on Saturday. Then on Sunday I am driving out of the Marina and turn the stereo up a little and notice the Sub is not working. It had a very faint kind of muffle sound and that was it. I start taking a look at the 3 amps and pulled out the fuses and noticed on one of the amps both fuses were blown. What would cause the fuse to suddenly blow? I have not replaced the fuses yet or done anything else. Any advise would be welcome. Thanks!

Getting wet or moisture in some way getting to the amps will do it. Replace the fuses and see if it does it again. Also check the positive and negative cables. Sometimes they get moved around and make contact at the terminals. Some amps place the teminals really close together which can cause this problem.