Solar Panel Location and Mounting Advice

[KingRichard]

I got this flexible 50W panel the other day and was planning to screw it to the deck where it's located in the picture. However, I don't want to put holes in the deck if there's a better idea.

It's a 26S and the charge controller is currently mounted right below the panel in the head or where it would be if it was still there.

Couple questions:
Better mounting locations? No bimini and it doesn't quite fit on the cargo hatch
Better mounting method? Can I silicone it to the deck right there? How bad of an idea is that
If I use hardware to mount it there. Short (1/2") screws into the plywood or through bolts?

Thanks for any ideas!

[Wyb2]

I would not glue it down. Those flexible panels don’t last forever so if you do, I suspect you might be kicking yourself in 4-6 years.

If it were me, I would through-bolt 4 of these just outside the 4 corners of the panel, and lash the panel through the grommets with some small cord.

https://a.co/d/4IYjPEe

(Auto-shortened Amazon link, not spam)

If you want to avoid holes, I would adhere (sealant or resin/epoxy) down some material (plastic or coated wood) that you can screw into and then do the same thing, 4 little deck loops for lashing down.

Through-bolts in the deck don’t bother me as long as they are bedded well, which for me means butyl tape. I don’t like screws because they will never let you know if they are leaking, all the water just ends up in the deck core. If there’s no core, then the screw will go all the way through, so you may as well use a through-bolt and avoid the exposed sharp point.

[KingRichard]

I would not glue it down. Those flexible panels don’t last forever so if you do, I suspect you might be kicking yourself in 4-6 years.

If it were me, I would through-bolt 4 of these just outside the 4 corners of the panel, and lash the panel through the grommets with some small cord.

https://a.co/d/4IYjPEe

(Auto-shortened Amazon link, not spam)

If you want to avoid holes, I would adhere (sealant or resin/epoxy) down some material (plastic or coated wood) that you can screw into and then do the same thing, 4 little deck loops for lashing down.

Through-bolts in the deck don’t bother me as long as they are bedded well, which for me means butyl tape. I don’t like screws because they will never let you know if they are leaking, all the water just ends up in the deck core. If there’s no core, then the screw will go all the way through, so you may as well use a through-bolt and avoid the exposed sharp point.

Thanks for the advice. You confirmed my fear with the screws, I think there's ply wood directly under it and I've been on a 25 that was soft from what seemed to be moisture getting the core.

Question though, why use tie downs? I had always imagined bolting through the grommets, seems like the panel would be ok.

[Wyb2]

Thanks for the advice. You confirmed my fear with the screws, I think there's ply wood directly under it and I've been on a 25 that was soft from what seemed to be moisture getting the core.

Question though, why use tie downs? I had always imagined bolting through the grommets, seems like the panel would be ok.

You could probably just bolt through the grommets. There are a bunch of small reasons that make me want to go a different way, but it would probably work fine.

The biggest is bedding. The panel is plastic, so might not play nice with polyurethane (4200) or polysulfide (life caulk). Silicone I think is safe for most plastics, but I really don’t like silicone on gelcoat. If you ever have to redo silicone, it leaves a residue that nothing will stick to (not even new silicone) and is impossible to clean off. You can sand it away, but if you are on textured non-skid, that’s pretty much impossible as well. The only silicone I see recommended for boats is architectural glazing (Dow 795) for setting glass or plastic windows into metal frames. It takes 7+ days to cure, but it has better adhesion and UV resistance than hardware store stuff for bathrooms. It may also leave less of that residue, but that’s less of an issue on non-porous metal and plastic anyway.

All that to say, I would use butyl tape, which is what I use for most things anyways. But butyl tape really likes to be compressed, it doesn’t glue things together the way curing sealants do. I’m not sure I would be comfortable using a bolt and fender washer and really tightening down on the panel grommet. Maybe it would be fine. Maybe use a nut or two and washers to create a kind of post that captures the grommet? So from top down: bolt head, fender washer, 1 or 2 stacked hex nuts inside panel grommet, washer, butyl tape, deck, washer, nut.

It’s possible I’m just over complicating it.

[KingRichard]

It’s possible I’m just over complicating it.

I think everyone with a sailboat is guilty of that

I really need to buy some butyl tape, everyone makes this stuff sound amazing. Guess I should try it on this project!

[dlandersson]

My solar panel is mounted on my starboard stern on an knob that can rotate 180 degrees. A PO did it, can't take credit for it.

[pitchpolehobie]

My solar panel is mounted on my starboard stern on an knob that can rotate 180 degrees. A PO did it, can't take credit for it.

Doesnt it seem like our "PO" can simultabeously be the best and the worst.

[KingRichard]

My solar panel is mounted on my starboard stern on an knob that can rotate 180 degrees. A PO did it, can't take credit for it.

Knowing what I know now, I think your PO had the right answer!

[dlandersson]

Never met the PO, but they did a lot of pretty cool things - and was willing to spend money to set my X up nicely.

My solar panel is mounted on my starboard stern on an knob that can rotate 180 degrees. A PO did it, can't take credit for it.

Knowing what I know now, I think your PO had the right answer!

[tomradams]

I added two 50watt solar panel and attached them to the aft rails using SeaStow Rail Clamps - 72669. I made a frame from PVC pipes to hold the panels.

[KingRichard]

I added two 50watt solar panel and attached them to the aft rails using SeaStow Rail Clamps - 72669. I made a frame from PVC pipes to hold the panels.

Certainly looks like they get good sun! I have rod holders in those positions and had thought of cannibalising an extension and doing something similar. I'm very surprised by how light and flexible my new panel is, so I think it might work and I'm glad to see someone else did it successfully.

[Wyb2]

Just saw a similar thread on a different forum where several people suggested 3M VHB (double sided) tape. I always felt that suggestion was a little oversimplified because last time I looked 3M sold like 20 different “VHB” tapes. But it might be a super easy solution. My understanding is there are very expensive boats out there with cabin windows held in with nothing but VHB tape, so it can be a very strong joint.

[KingRichard]

Just saw a similar thread on a different forum where several people suggested 3M VHB (double sided) tape. I always felt that suggestion was a little oversimplified because last time I looked 3M sold like 20 different “VHB” tapes. But it might be a super easy solution. My understanding is there are very expensive boats out there with cabin windows held in with nothing but VHB tape, so it can be a very strong joint.

This is a good idea! Might have to buy a couple of the thicker types and test them in inconspicuous locations.

Thanks!