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Old 09-04-2015, 11:56   #1
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How high should solar panels be mounted off the back for offshore cruising

I'm going to put some solar panels on my boat (~800W worth).

My first thought is to mount some davits to hold the dingy while coastal, and hold the solar panels up. I've heard stories of large waves crashing onto the davits and ripping them off/damaging the solar panels/etc.

My boat has a lot of freeboard. I would say the deck is at least 4+ ft above water level at the stern. I had initially thought about 26" - 36" davits lifted above the deck.

I'd kinda like to just buy these and move on to the next project, but a veteren cruiser warned against mounting panels on low davits.

How high above water level should the solar panels be mounted?
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Old 09-04-2015, 12:12   #2
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Re: How high should solar panels be mounted off the back for offshore cruising

If your boat is like most, they need to be high enough for you to go up and down the boarding ladder mounted on the stern without hitting your head on them.
I believe once you get them high enough for that, then they are pretty high off of the water.
On edit, that puts them usually at least as high as your Bimini top, but you want them up there so the top doesn't shade them anyway
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Old 09-04-2015, 12:17   #3
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Re: How high should solar panels be mounted off the back for offshore cruising

My boat is a double ender. I board on the side of it.
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Old 09-04-2015, 12:22   #4
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Re: How high should solar panels be mounted off the back for offshore cruising

You also want them high enough that a local water taxi/panga/etc coming up on your stern can't smash them, even if your anchored in a short chop.

(A friend has his smashed that way).
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Old 09-04-2015, 12:34   #5
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Re: How high should solar panels be mounted off the back for offshore cruising

If your going to mount them on the back above davits, I'd still want mine high enough so that the top couldn't shade them, that puts them up pretty high
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Old 09-04-2015, 12:36   #6
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Re: How high should solar panels be mounted off the back for offshore cruising

Sounds like "at least as high as your bimini top" is the consensus.
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Old 10-04-2015, 08:28   #7
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Re: How high should solar panels be mounted off the back for offshore cruising

high enough to stand under but low enough to clean if you need to.

And let's be honest here, if you are in conditions where waves might crash over the top of your bimini/davits/panels you aren't caring at that point about damage but concentrating on staying alive.
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Old 10-04-2015, 10:04   #8
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Re: How high should solar panels be mounted off the back for offshore cruising

This is an excellent question. I am grappling with the same issue, and I have decided to place them on the deck just forward of the dodger and on the dodger itself. To keep the boom from damaging the cells I am also installing a gallows.
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Old 10-04-2015, 10:55   #9
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Re: How high should solar panels be mounted off the back for offshore cruising

This is one expense we always allow;
we install a goal post arrangement on the stern - this is at bimini height and also take the place of davits. We dont use tilting frames as we believe a fixed mount is sturdier (but less efficient) that a tilting unit and also we dont have to think about constantly adjusting the angles. We also use this goal post to mounty/dismout our outboard engines. We use >900 watts and they literally run everything for us (fridge, freezer, a portable 95 litre two door compartment fridge freezer, made by National Luna - autopilot, radio's and radar, lights, nav lights, music and all the other essential items). Dont forget to consider shading by your boom, access to other equipment, interference with rigging/mainsheet, launching and retrieval of your dinghy etc. If you are worried about being pooped and your dinghy is hanging bleow like a giant bucket .......................
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Old 10-04-2015, 11:52   #10
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Re: How high should solar panels be mounted off the back for offshore cruising

I have just re-installed mine (2 96 cell units) with a new alu frame. They create the roof of my biminni. Yes, the mast creates a shadow but each panel can take it a still produce some power.
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Old 10-04-2015, 12:13   #11
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Re: How high should solar panels be mounted off the back for offshore cruising

I sailed around the Sea of Cortez between 2005 and 2009 and I didn't want to burn rotten dinosaurs or put up with the noise to recharge my batteries. I sailed up to San Diego and had a bimini frame built. Then I installed four solar panels as the bimini cover. Between those and two on the dodger I had 420 rated watts, easily enough to operate everything on my Cal 39. 12 volt refrigeration. 200 GPD watermaker. Radar. Laptop computer and plotting software. And more. It's high enough to be out of the way of any shade (except the mast) and both high enough and inboard enough to any reasonable seaway. My experience in the large following waves heading to Hawaii isd that the ass end of the boat lifts up at what seems to be the last moment before getting pooped. Solar panels at that height, but on davits aft of the boat, would not have been high enough.
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Old 10-04-2015, 12:16   #12
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Re: How high should solar panels be mounted off the back for offshore cruising

I mounted mine at bimini level so they act as an additional sun shade for the cockpit. Probably 9 feet above water level.
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Old 10-04-2015, 16:33   #13
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Re: How high should solar panels be mounted off the back for offshore cruising

We also made an 'aluminum solar bimini monstrosity' to hold our panels. I'm not sure if it is ugly, or not, but I am dang sure that way more electricity than we can use is beautiful. They make >50 amps in full sun, even though the split backstay is always casting a shadow on them.
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Old 10-04-2015, 17:35   #14
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Re: How high should solar panels be mounted off the back for offshore cruising

Well aft (to minimize shading) so above davits is perfect and with enough height to move comfortably underneath the panels for whatever's appropriate on your vessel in that area. Well aft also keeps the panels (relatively) free from sheets...and added height will also provide useable shading underneath the panels.

...and a plug from the sponsor would suggest to ensure your panels/cells are the best available, as in max efficiency in all conditions...overcast, low sun angles, high heat...SunPower!

Good luck with your install...good solar power is certainly worth the effort!
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Old 10-04-2015, 20:31   #15
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Re: How high should solar panels be mounted off the back for offshore cruising

Tried to attach these photos earlier.
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