I've got a 228 Seafarer, so not the same boat as yours or anything, but I like to keep a window squeegee, bottle of windex and a roll of paper towels on the boat for this very reason. On my boat, there's only one windshield wiper on the drivers side and then nothing on the passenger side. In the mornings when I go out fishing and there's a lot of condensation on the windshield and fog, then the squeegee works great to clear them off and if there's bird crap or anything else on there then the windex works well. The issue with the wiper blades imo, is that if the boat stays outside year round or even for months on end then the rubber on the wiper blades will crack and bend. Which won't get all of the rain or water off of the windshield. You can try some of the spray on products out there as well, I know Rain-X has a product that I've used on my cars where you spray it on the windshield and the water/rain run off without needing to use the wipers while driving. It's nice, but you have to apply it every couple weeks or so and I'm not sure how that would work with birds crapping on the boat and so forth.