First, you need three of whatever you pick. They will be connected directly to each of the batteries. Or you need a single 36 volt output panel, but that just means you take the physical size of the panels you are looking at, and triple them. (or take the capacity by 1/3, some result)
Now as far as capacity, might want to rethink that... Lets say you get three of the 6 watt chargers. If you have perfect conditions for charging 8 hours a day, you will put in 3.4 amp/hours per day per battery. An average group 27 deep cycle can have a capacity well over 100 amp/hours, so its going to take 29 days of perfect sunlight to charge that. The problem is that batteries also have self discharge, so its going to take more like double that. Toss in some cloudy weather, and it becomes impossible for the charger to even outrun the self discharge, let alone get ahead.
If you go to 3 of the 40 watt panels, its going to take about 5 days of perfect 8 hours of sunshine.
So those numbers are all under perfect conditions with a tracking mount system. A fixed panel is going to average less than half of its rated output for an average day. Also keep in mind that New Jersey averages 4.21 sun hours a day...
In other words, overcharging the batteries is the absolute LEAST of your problems! Solar panels are fine for minimal use systems and keeping already charged batteries topped off. If you plan on using them to recharge a dead 36v trolling system, you are going to be covering the entire top surface of your boat in panels and still having to wait a week or more for a full charge.
(have to wonder, why a bike helmet?)
