Member Forums > Modifications & Equipment
Arch for solar Panels
rbrtmccorkle:
High all
Bought a 1999 Ocean 42 and am currently outfitting for Long Term Cruising. I'm thinking the minimum additions I'll need are as follows:
1. Solar Charging System
2. Water Maker
3. AIS
My question today is are there any strong opinions on where place the solar Pannels? I've been looking online at some pre-Arches. A company in New Jersey sells these and has pic's of one successfully installed on a Bavaria 38. The arch looks tall enough to not obstruct the swim steps and appears to be fabricated out of 1 1/2" to 2" stainless?
Anybody have thoughts on different approaches?
Bob McCorkle
SV Chaos
Yngmar:
I've thought about this long and hard, and came to the conclusion that a stern arch is the best way to place solar panels when used as primary means of power generation (i.e. if you do not have wind power or a genset).
I've designed and built mine last year. It looks like the below. I've been meaning to write a proper blog article about it (some day), but meanwhile here's some bits I wrote on the YBW forum when someone asked a similar question.
--- Quote --- I went with the 2x 300W and am pleased with the results. The panels are mounted on their intended mounting holes (no modifications to the panels whatsoever, so the 10 year warranty remains intact). This is done by mounting each on two square aluminium profiles, with stainless bolts and nylon washers exactly as per solar panel specs. Those profiles are then bolted onto the stainless stern arch and give excellent support. They are not adjustable (I briefly looked at that, and the extra fuss and wobblyness aren't worth the hassle unless perhaps you sail in high latitudes). The panels themselves are rated to 160 knots wind speed for house roof installations, but the full installation is only good for roughly 100 knots before the aluminium profiles go and I suspect with the boat heeling and no house roof under the panels, the glass will simply blow out long before that. Panels can be strapped down to the big aft mooring cleats with ratchet straps over the top of both of them, should it come to that, but in such wind speeds the lost solar panels are probably the least of our worries.
Our panels do fit down the companionway hatch, but removing them and maneouvering them there in rising wind conditions would probably not go well, so for panels of this size that's a rather theoretical concern unless you get a long warning time ahead of bad weather.
You'll want to wire them in series, to get the high voltage into a MPPT controller (Victron MPPT 100/50 - good stuff) that lets you get maximum low light performance - that way they'll start producing useful output earlier in the morning and longer in the evening. The charger is to be installed as close as possible to the battery bank, so you have a short low-voltage (12V) run and a long high-voltage (less lossy) run from the panels. Victron has a calculator for wire sizes (XLS) somewhere that can be quite helpful.
--- End quote ---
--- Quote --- More photos, as requested. After long and hard thinking, I decided the only sensible and visually inoffensive way was to attach the arch to the pushpit. So we welded four "horns" on the pushpit to keep it removable, and the arch slides on those and is affixed with a bolt through each. While the pushpit was at the welder, I made up some large stainless backing plates for its toerail bolts. The rest should be fairly obvious from the photos. It's all 25mm tubing, but the long pieces across the beam have a 22mm tube inside the 25mm, which according to the builder was stronger than any thick-wall tubing he could find, and I've learnt to trust the guy. Before mounting anything on it, I've done a few pull-ups in the center of the top beams and it did not invert. I'm not the slimmest
To reduce shear, there is one brace going from a tang to an inboard corner of the pushpit. This is not yet installed in the photo, but you can see the tang and a bungee cord in the approximate location. I can climb up the sides to clean the panels and it does not bend much. It's also a great place to lash more stuff onto! ;-)
Visually, I made sure the arch extends the angle of the forward vertical tube of the pushpit, so it wouldn't look funny and then raised it high enough so I could step off the aft deck (it's a CC, unlike yours) without mashing my head into a solar panel, and step through the transom as well. This puts it neatly behind the backstay, with the panels protruding forward (and aft) of it on both sides. I also made sure the panels were well within the bounding box of the hull, so the boat length wouldn't increase and the panels couldn't hit anything if maneuvering near tall objects (walls, pilings, etc.). It's wise to angle the panels slightly aft and outwards so the water can run off them and doesn't fall noisily on the transom (we sleep there). Panels are two LG Neon 300W 1.6x1m size.
The panels are attached with stainless bolts as per the LG installation manual, except with additional insulating nylon washers between the stainless bolts and the aluminium. The clever part (a friend came up with the idea) was how to clamp the profiles to the tubes. You can see the two plastic bridges around the tube, and a third one (with nuts held in place by a bit of hot-glue) is hot-glued to a piece of slim cable trunking and slid into the profile from the end until the holes line up. Then the bolts are tightened into those and the cable conduit simple pulled out with a tug, which breaks the hot-glue off cleanly. Looks nice and vastly cheaper than any square-to-tube clamps I could find.
--- End quote ---
rbrtmccorkle:
Thank you for your insightful reply. Looks like I have the 42 ft version of the same boat and I had not thought about attaching to the stern pulpits, but like the idea very much.
Some questions:
1. The factory stern pulpits are not 2" stainless - so when you had the arch fabricated in 2" stock - it looks like you also had 2" pulpits fabricated?
2. Any chance you have any drawings you would be willing to share?
3. My radar dome is on a post mounted aft of the stern Pulpits. I had been concerned about the following:
A. The possibility the the Arch and solar Pannels could in someway interfere with the radar?
B. The radar dome casting a shadow on the Pannels?
C. Any thoughts on making the height of the Arch higher or lower than the dome (I noticed your dome is mounted on the mast) but I'm trying to keep projects to minimum in order to get cruising as soon as possible).
Your boat seems ready to go or very near. So would appreciate your insights.
Bob McCorkle
SV Chaos
Yngmar:
--- Quote from: rbrtmccorkle on December 30 2017, 16:39 ---1. The factory stern pulpits are not 2" stainless - so when you had the arch fabricated in 2" stock - it looks like you also had 2" pulpits fabricated?
--- End quote ---
Everything is 25mm tubing (with an insert across the arch as described above). You don't need more unless you also want to use it for davits, then it needs to be much sturdier.
--- Quote ---2. Any chance you have any drawings you would be willing to share?
--- End quote ---
Just got some sketches that I gave the welder to give him an idea of what I want. I was of course there for every step of the build and it underwent several more steps of evolution during that. As nothing on a boat is ever straight, drawings with dimensions don't really work and when I suggested to make some, the welder (a very experienced guy) just said "please don't". We constructed and aligned the thing in place, tack-welded it on the boat and then took it to his workshop to seam weld and polish. Happy to share the sketches I have.
--- Quote ---3. My radar dome is on a post mounted aft of the stern Pulpits. I had been concerned about the following:
A. The possibility the the Arch and solar Pannels could in someway interfere with the radar?
B. The radar dome casting a shadow on the Pannels?
C. Any thoughts on making the height of the Arch higher or lower than the dome (I noticed your dome is mounted on the mast) but I'm trying to keep projects to minimum in order to get cruising as soon as possible).
--- End quote ---
That's awkward. Only choice is to have the radar above the arch and panels, as otherwise they would very much interfere with the radar. That means the fat blob of a radome will cast a shadow on the panels, defeating much of the point of building an arch in the first place. A better place for the radar would perhaps be the mast, although that has downsides too - ours sometimes gets caught by the Genoa, although usually shakes free and never did any damage to it. I've seen gimbaled radar mounts on the backstay, about halfway up, so less of a problem than on a pole.
--- Quote ---Your boat seems ready to go or very near.
--- End quote ---
We've "gone" last June and are now in Portugal. The anchored picture above is in Culatra (near Faro) :)
rbrtmccorkle:
This is so helpful - thank you and Happy New Year.
I think I know somebody who could fabricate this and yes I've worked with wonderful welders in the past who only worked off conceptual drawings.
I was thinking about Davit potential, but in truth given the real estate available on both our boats - I have a very small tender, on any serious passage it would be lashed to the bow, on shorter trips it can survive nicely either on the bow or being towed - so Davit's clearly fall on the nice to have list and there are many things that my outfitting budget could be better spent on.
Thanks again and Blue Skies and Fair Winds on your trip
Bob McCorkle
SV Chaos
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