Steve, what boat model do you have? I looked but may have missed it. More speakers could definitely help. The problem with fewer speakers is you have to push them so hard to hear anything and those closest to them will hear EVERYTHING while you may struggle. If you go with small tweeters though at the helm area, I doubt you'll enjoy the sound. With the wind in the boat, most low frequency notes get washed away as it is and unless you have some subs pumping, it's hard to get good bass response while underway. The tweeters will likely give you so much high end sound I think it will sound shrill and hissy. If you've got a place to add speakers near the helm, that will definitely help. Anything you can do to spread the sound out. Also, if you have a recent Sony head unit, it may have a feature called DSO on it. I'm not a real big fan of too much processing or sound fields in my systems but it kind of raises the sound of the speakers and gets it up off the floor of the boat. There are usually 3 levels which you could play with to see if you like or if they help.
More speakers, maybe an amplifier if you don't have one now can really help. If you can get speakers up high, even better.
O'
"Little Mascara 3"
266BR,496 MAG-Bravo III