How to run wire through masthead

[farmer.leo]

While the mast could be taken down, it won't be for this job.

We're looking for suggestions for running a wire to the top. I've got a nylon snake, twine, etc.
What I'm unsure about is how to get the last part, through the mast cap.

I'm guessing that the four bolts (three shown each in a red circle) merely attach the mast cap to the mast.
But I wondered if I loosened the nuts, if some bolt would plunge 45 feet.

From what I can tell, at least at the bottom of the mast, there is an internal tube of some sort, perhaps even plastic PVC pipe. A vertical
cross section of this pipe, which might run fully to the top, appears in the blue dots, part of which is offscreen.

Perhaps this is simple, but I've never done this type of job. I have been at the top of this one, and the view is great, but I'd rather know
what I'm doing before going up again.

Thanks again Gentlemen

Edit: added another picture

 

[tonygibbs]

I would imagine that the internal tube is where the wire goes through, a sort of conduit pipe. I replaced the wiring on my mast recently while it was unstopped. I taped the new cable to the old from the base of the mast, then gently pulled from the mast head.

 

[john_morris_uk]

The usual method is to drop a thin line from the masthead downwards with a length of chain on it (or some small shackles in a chain) and then hooked out from the bottom of the mast. The line is used as a mousing line to pull the wire through.

If there is a conduit then check very carefully to see if there is a mouse line already left in place?

If there isn't a mouse line through the conduit, then I would start thinking about using one of the wires already in the conduit to pull a mouse line through and start again with the whole mast wiring.

 

[KAL]

The usual method is to drop a thin line from the masthead downwards with a length of chain on it (or some small shackles in a chain) and then hooked out from the bottom of the mast. The line is used as a mousing line to pull the wire through.

If there is a conduit then check very carefully to see if there is a mouse line already left in place?

If there isn't a mouse line through the conduit, then I would start thinking about using one of the wires already in the conduit to pull a mouse line through and start again with the whole mast wiring.

Yep - I used a length of mousing line attached to a basin sink chain, but am told a bike chain is even better. You could use the slot that is already at the top of the mast and feed from there. In other words you don't have to take the cap off. Would go from the top and let gravity help. If you use a very large plastic cable tie inserted into the base of the mast (keep hold of the two ends and let the middle expand like a hoop inside the mast) you can pull the chain out quite easily (that is, if you don't use John's suggestion of making use of an existing wire/cable to pull the new one through, which is even easier).

 

[prv]

I think the red-circled nuts are on bolts that have a 90º bend just before the head, with the head passing through the mast wall just below the cap plate (visible in the second photo). My cap is attached with two such bolts.

Taking the cap off is a non-starter anyway, as it looks like the shrouds are attached to it.

Pete

 

[alahol2]

View attachment 43238

I'm guessing that the four bolts (three shown each in a red circle) merely attach the mast cap to the mast.
But I wondered if I loosened the nuts, if some bolt would plunge 45 feet.

View attachment 43239

I may be reading it entirely incorrectly but it looks like there is a fair amount of standing (not to mention running) rigging attached to that mast cap. I can't see how you could possibly release it whilst the mast is standing.

Edit: Must type quicker.

 

[farmer.leo]

You're probably right. Now that you mention it, it looks like the mast cap is a functional load bearing element.

It also looks like the stay rides with a pin holding it on top of a slight arch. Probably not a good spot to sneak a wire down, given the play that is likely.

The lighting rod seems to pass through a hole with a lot of extra room. I should also get a photo of where the wind speed wire enters the mast.

 

[farmer.leo]

Yep - I used a length of mousing line attached to a basin sink chain, but am told a bike chain is even better. You could use the slot that is already at the top of the mast and feed from there. In other words you don't have to take the cap off. Would go from the top and let gravity help. If you use a very large plastic cable tie inserted into the base of the mast (keep hold of the two ends and let the middle expand like a hoop inside the mast) you can pull the chain out quite easily (that is, if you don't use John's suggestion of making use of an existing wire/cable to pull the new one through, which is even easier).

To be more specific, the big unknown part of the job is how to get the wire from above the cap into the conduit. There is no old wire, all current wires are working and passing through a sealed rubber grommet at the deck, so I'm reluctant to borrow one. I'm going to check again if there was a "mouser" line left.

I was going to feed the wire down from the top, but it will likely all go better if I feed a string first. I'll try using a thin chain attached to the string to help with gravity and getting around bends. Perhaps a stiff zip tie could help guide the chain towards the mouth of the conduit.

Update: there is no mouser. Wondering how to get the chain to "release" from the stick - once it's in position. And not sure how I'll be able to know when it's in the right position.