Sealing wires into the mast head

[jarcher]

How do you guys seal wiring that comes in and out of the mast head for lights and such? I will be rewiting my mast this coming week, and I;ll have a radio feedline, light power wires and a signal cable from a wind transducer to get inside the mast at the head.

Are there special things for sealing the wires, or is it a matter of grommets and sealant?

Thanks...

[geraldartman]

I do not think you want to seal them completely. You want the inside of the mast to circulate air to dry out. Masts are not watertight to my knowledge. The primary issue is wear. Grommets provide the cushion to avoid sharp edges of metal holes. The insulation on the wire(s) should be sufficient.

[jarcher]

Originally Posted by geraldartman

I do not think you want to seal them completely. You want the inside of the mast to circulate air to dry out. Masts are not watertight to my knowledge. The primary issue is wear. Grommets provide the cushion to avoid sharp edges of metal holes. The insulation on the wire(s) should be sufficient.

So its okay if water runs down the wires?

[tager]

Unless you plan on frequent knockdowns, this would be mostly rainwater. Not as big of an issue as salt spray.

[jarcher]

Okay thanks, I'll find some rubber grommets then and just run the wires through holes down the top.

[J36ZT]

I'd seal the wires where they enter the mast but not where they exit. Ask a rigger for specific products they use. In the least, use marine silicone.

Wires should be in conduit...unless you like to piss off your neighbors...

I see an electrician's fishtape and some stuff called Tefgel in your future.

Thanks,

Skipper, J/36 "Zero Tolerance"

PS Use the Tefgel to bed any hardware, NOT to seal around the wires.

[sailingdog]

Tefgel isn't used to "bed" hardware, but to coat fasteners, so that the fasteners and the mast are less likely to have galvanic corrosion occur between them. You can use Lanocote to much the same end as well.

I would recommend that you seal where the wires enter the mast, but leave the mast bottom unsealed. The rubber grommets aren't for sealing, but for chafe protection.

[jarcher]

Thanks...

I mostly want to remove stuff. There is an old windex and an old anemometer that need to go away and be replaced by a new wind transducer. I'm expecting to find a bunch of holes when I finally see what's up there.

I have never heard the existing wires banging around so I am hoping that there is a conduit. Fingers crossed.

[J36ZT]

Thanks Sailingdog for the correction on "bedding" and Tefgel. I couldn't think of a better word at the time; bedding would imply a watertight seal which Tefgel (or Lanocote) doesn't really do.

Jarcher, if you do find a bunch of holes from old hardware at the masthead, I'd seal whatever doesn't have a fastener going through it.

Again, ask a rigger (which I am NOT) if you have questions or are running into problems. There are one or two riggers that do post on sailnet.

Sounds like you've got things under control though.

Skipper, J/36 "Zero Tolerance"

[jarcher]

Originally Posted by J36ZT

Jarcher, if you do find a bunch of holes from old hardware at the masthead, I'd seal whatever doesn't have a fastener going through it.

Again, ask a rigger (which I am NOT) if you have questions or are running into problems. There are one or two riggers that do post on sailnet.

Sounds like you've got things under control though.

Well I don't know if I have it under control, but I did decide not to risk pulling the mast. The marina owner told me that its not at all uncommon for that kind of problem to happen. So, the plus side is that I launch tomorrow, the down side is that I climb the mast this weekend