I have 2 6.5" pioneer 4 way speakers in homemade cans on my tower with about 75 watts going to each one and I can hear them fine 75 ft back. Not the greatest out in the flats, but well enough.
WW could do a DIY article on my boat! I have DIYed almost everything and saved a ton, maybe when I am done with my diy bimini, tinted windshield and partial wrap I will get ahold of dave. Less than $350 for 15" vinyl stripe, bimini and tinted windows