How much wattage are you getting out of your panels on the Hatches?
I would venture to think that is is very low wattage.
If you want to use solar panels to charge your battery you will need some serious square footage for a product like PowerFilm:http://www.powerfilmsolar.com/rollable- ... argers.php
Solar panels that you can either fold up or roll up are not even close to what NASA sticks on their satelites in terms of output.
Here's the next question: Where do you live? Look up the average hours of sunlight in your area.
Just to gain 10 watts on Powerfilm will use up half of a tramp and set you back a serious chunk of change.
If you go that way, I suggest a Morning Star 7 amp solar controller at about $80-$100. If you are only interested in pulling power when your boat's 'asleep' consider a standard 30-50 watt Sunforce solar panel like what they stick on the roof of those lux homes in the middle of Nowhere. This is the best tech at this time and it WILL charge your battery in a day. Without the Controller, your battery will blow up, quite as simple as that...ergo the extra $80-$100 dollars.
You also need to keep your boat covered or the UV will seriously shorten the lifespan of your boat and it's components. The Cover is Bombproof (and not meant for hauling. It is a simple $150 investment to keep your toy shiny and new. (Btw: the built in bright red flag on the end of my cover is now very pink after sun exposure for 3 months. Nothing more on this subject need be said, I think)
If your dog jumps on your tramp, your PowerFilm may now end up being Dog Doodies (and a possible afro on your dog, if he get's it right....!.
M8, I wish there was another way around this, yet until the efficiency of the products very sharply rises and the nutty price syndrome drops way steep, I suggest you simply connect a good sealed gel cell battery in a Pelican box with a waterproof connection and haul it ashore and connect it to your batt charger after daily use.
Trust me, it will save you a ton of money and less torn out hair. (If you need longer use buy the same battery and setup, times two, at twice the weight)
(However, if you want to talk about Wind turbines....well now, we're talking... but not on a 16/18' daysailer...try a 35 to 40 foot plus offshore yacht that can mount 2 helix
wind turbines on a very solid base).
Yah, a buddy of mine almost literally got decapitated when the prop from his old school wind generator came loose in heavy seas and almost killed him and his wife.
Nothing comes easy, my friend, or we would all be sitting on top of Mt Olympus, dictating to the Greeks how to get out of their horrible financial mess of tax dodging and bribes to get anything done in this messed up country..
Be well (remember also, that those twist and seal hatches are a soft plastic black hatch and they need a ton of waterproofing if you run bolts and wires through them...and constant checking for leaks as a bolted on addition can warp the underneath seal unless the nuts and bolts are properly fastened in turn (like adding torque when you change a tire)