Tuesday, September 2, 2014

Solar Panel On Stern Pulpit

Photovoltaic Panel On Stern Pulpit
PV panel hung on the stern pulpit of Speakeasy.

After stringing wire and installing the controller and battery monitor, I thought installing the photovoltaic (PV, solar) panel would be a breeze. This has not been the case at all. My first mistake was thinking that a single bar would support the panel, which is over 30 pounds and it's dimensions are nearly 3' by 5'. I had Sterling (Sterling Sails) create a bar made of 1" stainless steel that spanned the aft Bimini from starboard to port. Brian, our club's dock master, and I attached the panel to this bar and judged it "too floppy" to be trusted in wind and waves. We removed the panel and stowed it in the salon for a month while we sailed around Lake Michigan. 

While out on the Lake, I saw a few PV panels affixed to Bimini stanchions and in all cases two bars were used. I needed to go back to Sterling. I also did some web browsing and noticed that a New Zealand sailor kept his panel on his side rail, which allowed him to bring the panel in close during poor weather and to angle the panel toward the sun during better conditions. I also saw this arrangement on a sloop in Marina Kremic, Croatia. This got me thinking about placing the panel on the stern pulpit, which is the only rail wide enough to hold the 5' long panel.
I saw PV panels on a boat in Croatia similar to this setup.

The benefits of having the panel lower is that it catches less wind and can be removed more easily than atop the Bimini. The issues include access to the ladder and swim platform, which is a matter of safety. Borrowing from the New Zealand sailor! I added two quick-release plastic hangers near the side of the panel and began to fashion an angle adjuster made from a marine antennae adjuster affixed to a vertical bar made of PVC similar to the one the New Zealander made.  I also attached two sail ties from the bimini structure above the panel secured to the Bimini structure. These two points of contact seemed to add more support than the single bar made from the PVC and antennae adjuster. 

When the panel is parallel to the water, the ladder can be raised and lowered and one can duck under the panel to reach the swim platform. This is a good solution when we leave the boat unattended for days or weeks. However, when actively sailing, I'd rather have the panel out of the way above the Bimini. So, Sterling will have to add another bar up top.
Typical PV panel hung on davits.
Each PV panel is hung from a single rigid bar.

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