How to secure stuff behind the electrical / breaker panel

[N.A.]

I am finally getting around to installing my AIS (well, more motivated as my local race organization now requires AIS; I have been delayed by the hassles of the tiny wires (have seen Christian's post re: those; thanks for that!) and the need for the NMEA 2000 backbone/trunk line adding complexity for me.)

But in the simplest case, I simply don't know how to secure it behind the panel on my E34 -- can I just screw stuff into the backing there (which I presume is some sort of liner and not the hull?) I was thinking of putting the antenna splitter/amp, Vesper AIS, and a piece of NMEA200 backbone on a piece of plywood and screw that back behind the panel... which beings me back to the screw question.

As an aside, I was thinking of wiring the AIS/backbone to power via a panel breaker, so I can turn it off while inside the (crowded) bay, but wire the (powered/amplified) antenna splitter directly to the bus pars since it always needs to be on if I want the VHF. But maybe the backbone needs to always be on in the future? And maybe one should never wire anything to power that doesn't go through a breaker... feel free to advice there too.)

Any thoughts appreciated!

 

[southofvictor]

I’m working on this myself right now so interested to hear what others suggest. So far I’m thinking of using Christians idea of using construction adhesive rather than more time consuming epoxy to bond some plywood pieces to the hull directly behind the panel. That way I’ll have more space to screw into. Does anyone know a downside to this? So far all I can think of is potential moisture getting closer to / onto terminal strips or bus bars from ingress at the toe rail or stanchion base above and coming down the hull, so I’d want to factor that into what gets mounted there and make sure to add drip loops.

 

[Christian Williams]

I did disconnect the drain for the E38 side-deck cowl, which went right through my electrical panel.

Otherwise that area ought to be dry as a bone. Any old slab of plywood painted white and stuck on with $3 worth of construction adhesive.

 

[Pete the Cat]

I’m working on this myself right now so interested to hear what others suggest. So far I’m thinking of using Christians idea of using construction adhesive rather than more time consuming epoxy to bond some plywood pieces to the hull directly behind the panel. That way I’ll have more space to screw into. Does anyone know a downside to this? So far all I can think of is potential moisture getting closer to / onto terminal strips or bus bars from ingress at the toe rail or stanchion base above and coming down the hull, so I’d want to factor that into what gets mounted there and make sure to add drip loops.

I have always used construction adhesive and had no problems attaching marine plywood for electrical and even for providing a surface in the laserette to attack line hanging hardware. You do need to figure out how to hold in place while it cures. I have used duct tape successfully in some places. I have also used a screw barely tapped into the glass just to hold in place until the construction adhesive sets up. I am not sure how this would effect moisture in the area--that seems to be a separate issue to me.

 

[peaman]

I have used 4200 to secure small backboards or mounting boards to rough surfaces like the hull itself, but I have not tried it on the smooth gel coated liner. I paint the plywood boards before installing, for a neater look, and reduced chance of moisture absorption. My 32-3 has hull lining within the panel wiring cavities, so I simply screwed terminal strips and ground bars to that.

As for wiring, I used a circuit breaker labeled "Radio" to power my antenna splitter, AIS, and VHF. I installed a toggle switch for the AIS, and the VHF has its own on-off switch so I can choose what gets powered.

My DC panel also has a circuit breaker labeled "Instruments" which I used for power to the NMEA2000 backbone, as well as my wind and speed instruments.

All +12V wiring should be suitably fused, which means that if you go from a circuit breaker with big wire, and you connect that to a tiny wire, you should have a fuse for that tiny wire. With more devices, the extra fuses can get tedious to the point that it might be worthwhile to consider a separate fuse block, like THIS or THIS.

 

[N.A.]

Thanks, folks -- this is super helpful. The toggle for the AIS makes sense, and isn't that much more complex -- my plan was to put it all on a piece of plywood, then attach it and wire the remaining leads to the breakers. I don't think the AIS draws so much more than the VHF, but I guess I should check and see if they require different breaker/fuse sizes. Thanks for the fuse-block links.

I think I have a hull liner in my boat -- @peaman, what size/type screws did you use in attaching stuff to it?

 

[Loren Beach]

I think I have a hull liner in my boat

You might want to double-check that thought. Behind the panel is likely the roving surface of the hull.

 

[Prairie Schooner]

Construction adhesive or screws sound like the best plan here. For future reference, this system was advertised by Jamestown Distributors recently and it appeals to my tech-toy tendencies. It's been in the back of my mind, on the watch for a project where it makes sense.

But I always have to remind myself, KISS.

 

[bigd14]

I have used thickened epoxy to mount pieces of scrap boards about an inch thick vertically to the hull then screwed the plywood panel to those pieces. This leaves a gap between the panel and the hull for any overzealous screws and avoids water entrapment. The panel is also easily removed if needed. Construction adhesive would be easier than epoxy.

 

[Alan Gomes]

I have used thickened epoxy to mount pieces of scrap boards about an inch thick vertically to the hull then screwed the plywood panel to those pieces. This leaves a gap between the panel and the hull for any overzealous screws and avoids water entrapment. The panel is also easily removed if needed. Construction adhesive would be easier than epoxy.

View attachment 49205

Thanks for sharing this picture. This is EXACTLY what I have been planning to do to tame the rat's nest of wiring on my boat. Your picture is highly motivating!

 

[Kenneth K]

Like Peaman said, the 32-3 electrical panel back seems to be a continuation of the "liner" that backs the cubbies:



I haven't drilled into the liner behind the panel, but I did drill and screw into it aft of the cubbies to mount my solar charge controllers.


Just drill a test hole first, with a small bit, to see how much clearance exists between the liner and hull, and pick your screw length accordingly.