Unique way to mount a solar panel on a C34

[PaulJacobs]

Eight years ago I wanted to add a solar panel to our 1990 C34 MK 1.5 (no. 1068) to provide a means to remotely charge our battery bank when on a 10 -14 day cruise.  I looked at dozens of approaches.  I did NOT want hard panels at or near deck level, nor did I want the expense or less than aesthetic look of a davit-like structure.  I even thought about installing flexible solar panels on the coach roof, but realized that they would likely be very slippery when wet.  What to do?  I really thought long and hard, wanting a location that was extremely unobtrusive, not not negatively impact the C34 aesthetics, yet would be modest in cost to implement.  Then one day back in 2013 I was lying in Pleiades cockpit, on her mooring, reading a book.  At some point I stopped reading and happened to glance up at our split backstay.  Suddenly, I realized "why not utilize the split backstay to mount a solar panel"?  I made a few quick measurements and realized I would only need six SS wire clamps, a rubber grommet-like seal,  about 20 feet of positive and negative wire, and about 20 feet of 3/16" diameter Dacron line.  The advantages of this approach would be:

1.  EXTREMELY unobtrusive.  People often do not even SEE the solar panel until they are in the cockpit, and then only if they look up.
2.  EXTREMELY inexpensive.  About $25 for the whole mounting system, and about $200 for a 100 W panel & controller!
3.  Effective & rugged.  It has been up there for over 6 years, through sun, rain, snow, and 60 knot winds, and is still looking great.

I used a 10 foot stepladder mounted athwartships on the starboard & port cockpit benches.  Then I made a cardboard pattern of the solar panel and its frame.  On a windless day with a friend we held up the panel so it was about 10 feet above the cockpit sole, and marked the locations on the cardboard pattern where the split backstays touched.  Then, we very securely attached a SS wire clamp to the starboard split backstay about 13 feet above the cockpit sole, and a second such clamp at the same height on the port split backstay.  Next we attached two 10 foot lengths of 3/16" diameter Dacron line (3/16" for both strength and long-term UV resistance), one just above the starboard clamp and another just above the port clamp, with double clove hitches (sometimes known as a Magnus hitch), and then twin half hitches to the working part of the line.  The point is you REALLY do not want this knot to slip in a seaway.  Then, we drilled small holes (3/16" diameter) in the aluminum frame that fits around the solar panel - along what would be the aft transverse edge, at the separation distance marked on the cardboard pattern.  Next, we drilled two 1/4" diameter holes in what would soon become the fore portion of the panel at the P&S bottom outboard corners of the frame, and mounted both S&P 1/4" SS eye bolts with lock nuts directly to the frame corners. 

Now, one of us held the actual solar panel and its frame in position while the other of us screwed the 10 foot high twin wire clamps through the aluminum frame and very snugly secured all four lock nuts.  Now, we ran the starboard Dacron line from its 13 foot high clamp elevation, down to and through the starboard eye three times (to intentionally generate significant friction), and then down to another starboard wire clamp about 8 feet above the cockpit sole, and tied a temporary knot just to maintain tension.  Next, we repeated this process on the port side.  Finally, we increased tension on both the P&S sides until the frame was extremely snug, level, and the tension on both sides felt about equal.  At this point we secured both lines with Magnus hitches just below the 8 foot high clamps, cut off and burned the tails, and then used white rigging tape to cover all the knots.  Next, we ran the dual electrical leads down the starboard split backstay, securing them with small nylon wire ties about every 8-9 inches, ran the wires through a small hole (subsequently sealed with a rubber grommet-like seal) into the starboard lazarette, under the quarterberth panel (again secured with nylon wire ties so the twin wires would not interfere with other hoses), and finally to the solar panel controller mounted under the quarterberth seat, near the refrigeration compressor / fan.  Finally, the positive and negative solar panel wires were run under the galley and directly to positive and negative house battery connections.

The system has been operating for seven years.  The four (3 house + 1 engine) group 31 batteries (about 400 AH total capacity, 200 AH "useful" capacity above 50 % battery charge status) have NEVER been below 12.0 volts over the past seven years!  And, since properly charged batteries will NOT freeze, I can leave them aboard all winter, which saves a lot of effort each fall and each spring.  I was down at the boat yesterday (3 February).  Even with heavily overcast skies, in the dead of a RI winter, and with non-optimal orientation of the boat on the hard relative to the sun, all four batteries were at 12.4 volts!

I mention all of this simply as a "totally different" way to mount a 100 Watt solar panel on a C34.  Oh by the way, the resulting geometry neatly clears the mainsail leech by about a foot, so there is zero interference with the mainsail, and since the panel ultimately winds up in a plane perpendicular to the plane of the split backstays, it tilts down at about a 20 degree angle, so rainwater nicely cleans it, runs off it,  :clapand even washes off bird poop!  I do expect in another 3 - 4 years I likely will need to replace the Dacron line, since just like old sailors nothing ever lasts forever!

[KWKloeber]

Pictures, please.

[PaulJacobs]

I realize this thread is absolutely crying out for some pictures.   

I have probably a dozen photos of Pleiades - both on her mooring, at a guest dock, and even a few taken by friends from their boats while we were sailing.  Unfortunately EVERY one of them exceeds the file size limit for this message board.  All the previous photos were taken with a digital camera.  Perhaps Nancy can take some photographs with her cell phone that will NOT exceed the file size limit.

What I would really like to show is one side view of Pleiades on her mooring.  Even KNOWING exactly where the solar panel is from my earlier note, it is STILL hard to even see it!  Then I would like to show a different angle where the panel is more visible - to help explain how it is attached to the split backstay.

Paul

[Jim Lucas]

For what it's worth, the PO of our Calypso had installed two panels on a custom arch. It was one of the things that really caught my eye on this boat as I love the lines of the 34's w/o too much added structures that I feel take away from the look.

Mine probably isn't that unique but I'm interested to see how Paul's approach works in relation.

[Jim Hardesty]

Unfortunately EVERY one of them exceeds the file size limit for this message board.  All the previous photos were taken with a digital camera.

Paul,
Try this,
https://c34.org/bbs/index.php/topic,4053.msg23052.html#msg23052

if that doesn't help just google it.  Lots of ways to resize pictures.
Jim

[KWKloeber]

Pleiades at her mooring in Wickford, RI.
Notice that at first glance you barely even see the solar panel.  On closer inspection - now that you know where to look - you can just barely make out the solar panel above and aft of the aft end of the boom.
I was just down to the boat about an hour ago, and I realized that my memory was not exactly perfect (I am not complaining, some people my age don't even recognize their wives!).� The upper S&P wire clamps are actually about 11.5 feet above the cockpit sole, not 13 feet. The aft portion of the solar panel frame is indeed at about 10 feet, and the lower S&P split backstay wire clamps are at about 7.5 feet above the cockpit sole.

The second photo (492) is more of a closeup.
Be careful, this photo almost creates an optical illusion.  The S&P 3/16" Dacron lines go from the S (or P) split backstay upper wire clamp, forward and down to the SS eye mounted on the outer lower corner(s) of the aluminum solar panel frame, and then aft and down to the lower split backstay wire clamp.
This forms two parallel triangles, and when the line is drawn taut, the result is that the solar panel does not even budge!
Nancy and I have been sailing in 6-foot seas, with 45-knot winds, and glanced up to note that the solar panel is extremely secure, and at most is doing a tiny "vibrational dance" even under these severe conditions.

The third photo (501) shows another "typical" view.
I have seen lots of sailboats with solar panels. Some have elaborate structures near the aft lifelines, or near the pushpit, which I believe detract from the C34's lovely aesthetics, and represent more things for lines to snag, or people to bump into.� This is the only solar panel installation I have ever seen which does not snag lines, or people, does not adversely affect aesthetics, costs only about $25 (not counting the panel & controller), has stood up to salt spray, large waves, winds up to 72 knots (while on anchor) and seven years of UV, and still works wonderfully well.

[Gary Brockman]

A very cool installation. It looks like the split in your backstay was raised quite a bit and that you gave up having an adjuster for fixed tension with turnbuckles. 

[Ron Hill]

Paul : Back in the early 1990s I published a chart that showed:  Voltage Reading    Approx. State of Charge    Hydrometer Reading
                                                                                                   12.75                            100%                         1.265
                                                                                                   12.50                              75%                         1.225
                                                                                                   12.50                              50%                         1.190
                                                                                                   12.00                              25%                         1.155
                                                                                                   11.75                              00%                         1.120
I've just listed 5 of the 14 points of that chart. 
So each .05 volts represents approx. 5% of charge. 
This is battery steady state at rest!!   FYI

A thought   

                                                                                                   

[Stu Jackson]

A very cool installation. It looks like the split in your backstay was raised quite a bit and that you gave up having an adjuster for fixed tension with turnbuckles.

Gary,

Many of us raised the split in the backstay because the OEM setup ended up having the splits hit you repeatedly in the head.  My wife said she'd rather do that!

Many of us added adjusters.  I went with a Garhauer plus a Garhauer vang to adjust.

The drawing is one that someone posted in Mainsheet in the late 80s, shows the same concept, but a different type of adjuster.  I used that to determine the height for the new split.