Solar cable gland on curved coaming?

[skunther]

I’m looking for a good solution for a cable gland to pass through my coaming. The coaming surface is curved and the glands I have are blue sea cable clams. They do not seem to sit flush. See attached images. Any thoughts or suggestions?

is there something better suited to a curved surface? Or a way to adapt these?

 

[dLj]

Depends on the amount of curvature. The first photo doesn't look like a lot of curvature, but I can't really tell.

Small difference, a thicker gasket.

More difference, you can make a small pad with filled epoxy. You can take a larger disk of wood, like teak of other wood of choice and form one side to match the curve, leave top flat for the gland.

dj

 

[Foswick]

That doesn't look like more curve than the gasket could handle on its own, but I would lay just a thin bead of butyl tape around the perimeter to make up any difference.

If it were me, and I was worried about it, I would just 3D print a shim in TPU. If you think it needs it, and you give me the specs, I can print one for you.

 

[east coaster]

I have three blue seas clamshell fittings on my 310 just aft of the port winch where the deck curved about as much as depicted in the initial photos. Have been in place for three years through summer heat, winter freeze and thaw as well as some serious rain, deck washing, no leaks at all. Had my doubts about their integrity but not now.

 

[PickledHerrings]

They make RV ones that will work better and you could shave off some in the middle of the curve w sandpaper easier. That's what I'd use.

 

[LLoyd B]

Butyl tape compressed all the way around as if the surface was flat. Otherwise modify the gland to match the curvature of the surface( best) or flatten the surface only to match the gland(difficult).

 

[skunther]

The attachment pictured next to the CableClam is one of two split backstay attachment points. It seems a bad idea to drill too close to the backstay attachment points. The flattest and most protected and convenient point to install the gland with the shortest run of loose cable is right between the backstay attachment and the Bimini tube I plan to route the cable down though. Is it too close to the backstay attachment?

 

[Foswick]

How is the backstay mounted on the underside? That is, is there enough room around the chainplate and any backer hardware? You'll need, of course, not just room to drill the hole but also enough extra room to tighten the nut on the underside of the gland.

I don't think you have a structural integrity problem by putting it there. The backstay doesn't rely on the lateral strength of the surrounding fiberglass. I just don't know how you will get good enough access from below to get that nut on and tightened. But, I suppose you've already sorted that.

 

[sailme88]

the curvature doesn't appear too great. The bigger problem is the non skid. Keep well off the non skid and the rubber bottom gasket should do fine.

 

[skunther]

How is the backstay mounted on the underside? That is, is there enough room around the chainplate and any backer hardware? You'll need, of course, not just room to drill the hole but also enough extra room to tighten the nut on the underside of the gland.

I don't think you have a structural integrity problem by putting it there. The backstay doesn't rely on the lateral strength of the surrounding fiberglass. I just don't know how you will get good enough access from below to get that nut on and tightened. But, I suppose you've already sorted that.

Access is clear, and there’s no backing nut on the CableClam 1001 - just mounting screws.

 

[skunther]

Here is the backstay, from both under and over the coaming. There doesn’t appear to be any anchoring securing the bolts the backstay is attached to, aside from nuts and washers.

 

[Foswick]

IMG_0303.jpeg shows the underside of the backstay attachment? No backing plate or chain plate? There must be something there I am not seeing. But, just based on that view, I would concerned about weakening the fiberglass in the immediate vicinity of that point. That attachment point seems wholly inadequate to begin with, though it does appear to be how it came from the factory. I guess someone that knows more than I do would have to comment on that, but that looks underengineered to begin with.

 

[dLj]

IMG_0303.jpeg shows the underside of the backstay attachment? No backing plate or chain plate? There must be something there I am not seeing. But, just based on that view, I would concerned about weakening the fiberglass in the immediate vicinity of that point. That attachment point seems wholly inadequate to begin with, though it does appear to be how it came from the factory. I guess someone that knows more than I do would have to comment on that, but that looks underengineered to begin with.

If you look at both sides of that attachment point, you will notice that it is a reinforced connection point. There is nothing inadequate of how that was done.

I'd look for a better place for that gland however. Drilling a hole in that area of the corner might not be the best thing to do. Got any more places you are looking to put it? Perhaps to the right of the stainless part you see in that picture? I would probably not want to put it within that curved region near that stay connection. That whole curve is actually part of that structural connection.

dj

 

[JBP-PA]

Access is clear, and there’s no backing nut on the CableClam 1001 - just mounting screws.

Yep, they seal around the wire because of the shape of the cap. It jams the rubber tight against round wires. It would "probably" work OK on a curved surface. You might need to orient the slit to make it tight. But I'm with dj, a bit too close to the backstay for comfort.

How about closer to the bimini mount? Make a little plate for it out of scrap fiberglass, G10, starboard HDPE etc. Use a grinder or sander to back it out for a nice fit. Maybe epoxy it in place, or use butyl with longer screws for the clam.

 

[jssailem]

butyl with longer screws for the clam.

When using butyl, I like through machine screws with a washer and nut on the inside. I dis like just running a screw (like a wood screw) into fiberglass.

I have seen it done and it works for a while then it fails and you have leaks that eventually create laminate failure.

 

[skunther]

This seems a legitimate concern. Has anyone experienced one of these cableclams failing in this way?

I’m now planning to avoid the area around the backstay entirely and mount it on the transom, adjacent to the shore power input, above the lazarette. Can I just drill through the wall with a hole saw? It doesn’t appear to be laminate construction.

 

[Foswick]

I’m now planning to avoid the area around the backstay entirely and mount it on the transom, adjacent to the shore power input, above the lazarette. Can I just drill through the wall with a hole saw? It doesn’t appear to be laminate construction.

I'm assuming that you mean it isn't cored. That is almost certainly true, in that location - just solid fiberglass.

But, yes, a hole saw will do the trick. It is not a bad idea to put a piece of masking tape over the gel coat, first. The theory there is that it helps prevent chipping your gelcoat. But, I am not sure it makes much difference. The better strategy is to just go really slowly until you are all/most of the way through the gel coat. A steady hand helps too, as I have chipped the gel boat when I thought I was well past the point I needed to worry, just because I changed the angle of the drill a bit too much.

 

[Project_Mayhem]

Run the hole saw or drill bit backwards through the first bit of gelcoat to reduce chipping. Even two 10awg solar wires don't require more than 1/2" hole. For the curve, use some BedIT butyl or 3M 4000UV, through bolt the mounting holes and call it a day

 

[jssailem]

You can use tape, but running the hole saw backwards will help to smoothly go through the Gel Coat without chipping. Then go forward and cut into the fiberglass.

 

[skunther]

So I taped the gel coat and ran the hole saw backwards until it penetrated the gel coat by a few mm. It didn’t take long. From there I ran the saw forward, and the hole came out very clean with no chipping. I did the same thing for the screw mounting holes (drilled backwards through the gel coat), resulting in no chipping and very clean holes. All is mounted in the flat surface adjacent to the shore power to avoid any compromising of the backstay and issues from a curved surface. Gland went on smoothly, some soap got the cables through the rubber seal smoothly (I didn’t cut it with a razor per Seaview’s instructions), and I’m very happy with the result.