I finally got around to adding solar panels to my Irwin 38 CC last month - and now I'm finally going to post about it.
The wife and I bounced around about towers and bimini's and davits as mounting options for a long time, and then had our decision helped by running down to 60% state of charge overnight.
Plan (a) was a pair of 315w panels mounted on a tower/arch. That got shot down by cost and the fact that we'd have looked like Skylab.
Plan (b) was panels on the bimini and a 315 on the davits.
That got shot down when I ripped out the davits (rotted base, not feasible to fix).
The option became run the diesel for 5 or more hours or run the Ryobi 2200 for 10 hours of so.
Or mount the panels on the stern rails.
A pair of Kyocera 140w panels mounted on 1 inch diameter stainless tubes via a rail mount kit from eMarine; coupled in to a Blue Sky 2121 MPPT controller that allows for later networking to additional panels.
I had the stainless bits and pieces delivered by two separate on line sources.
This won't work for everyone - a Center Cockpit has a big aft deck where unless it's a ketch nothing 'moves' while sailing. It makes a nice lounge deck at anchor, or a sun pad etc.. but no crew work/trimming etc goes on.
Note I went extra (the lower tube/rail) with the tubing as we intend to use the area under the panels to store jerry cans of diesel, gas, and water anyway - this will strengthen the area.
The panels are 26 inches wide and 59 long. I hung them off center with 8 inches hanging over the deck so they both take up less deck space inboard and are naturally weighted to fold over.
I don't have the cables tied in yet in these photos (they get seriously fastened later).
Most folks that do that put a support on the off side to hold them up.
I put a strap on them to hold them DOWN and level.
When coming into a dock I simply unshackle the strap (which is adjustable so I can angle the panel for the sun) and the panel folds over outboard and out of the way.
I have 5 inch wide toe rails and a 3 inch rub rail to fend off pilings and such, no chance of an accidental bump shattering glass.
The rest of the hook up is straight forward - find the cable runs that fit for your boat and drill, fill and pull. I went down through a locker, under the queen in the aft cabin and then followed the steering cables to the engine room where I mounted the controller. You can see by the light that it's working and in float mode.
Cable ties and such not yet in place, I'm terrible about taking pictures so you get what I got.
I got two 50 foot MC4 cables as part of the install - cut them in half (25 feet each) and that made 4 cables with 2 male, 2 female connectors.
I plugged the connector ends into the panels and ran the now cut/bare end to the controller. I spliced the positives to a length of short #4, the negatives to a short #4 (via a 3 way butt connector) - then put the #4 into a 30amp fuse block. Out of the fuse block and into the controller.
The only truly hard part (other than running the cable) was splicing the heavy cable down to connectors that fit the tiny screw on bits for the controller.
This controller is the cheap, out of sight one. I still intend to add a 315w panel to the davits once I replace the davits. That controller will be the one with the pretty panel, gauges and buttons, and installed next to my battery monitor (Victron BMV 602s).