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Wayne25 01-09-2007 12:43 PM

Mast wiring
 
I bought a 1976 Helms 25 this past Labor Day and sailed it until November. The perfect boat for my shallow bay areas here in Delaware. Now that I have the mast down for the winter (Deck mounted mast, hollow and no interior rigging) I want to add a masthead nav Tri-color/anchor/strobe, spreader lights, masthead/foredeck light and antenna. I plan to run RG-8U coax for the antenna and will use Blue Sea's Cable Clams for the coax thru deck fitting and for the upper mast penetration. I figure the Cable Clam at the top of the mast will also act as a coax strain relief. I know about the trick of leaving cable tie tales on inside the mast to stop the wires from slapping around.
I was going to use Anchor's 5 conductor mast cable for the wiring, but can't find information on the physical wiring of the lights. At what point do I remove the cable cover to expose the individual conductors? Do I run the cable to the mast top and fasten to some type of interior strain relief (If so what kind of relief and how?) and then run the individual conductors back down the mast to each light? Or remove the cable cover at the first light (the spreader bar lights) and run individual wires to each light above that point? But then how do you strain relief the cable? Do you use rubber grommets for the individual wires going thru the mast to each light? I guess I need to know the standard and correct way this is done without re-inventing the wheel.

Thanks for your help!

Wayne

pigslo 01-09-2007 05:14 PM

Open up the fixture and you will understand a bit better how the wires go. Any wire or cable that comes out of your mast needs to have a drip loop. This means for example when you rx8 coax comes out the side of the mast route it down towards the boat a couple of inches then back up to the bottom of the antenae. This allows rain to drip off the loop instead of into the mast.
pigslo

Wayne25 01-09-2007 05:21 PM

Thanks Pigslo. The same as electricians do with service wires coming into a building. Any thoughts my wiring questions inside the mast?

Wayne

pigslo 01-09-2007 06:23 PM

I would leave the cover on anywhere you canas the UV at the top of the mast is murder on insulation. My wires go up a pvc pipe that is riveted to the inside of the mast. They barely fit thru so support was never an issue. Just putting in the drip loop and attaching to the mast will provide some support. Give this board a day or so and you will get a better anser than mine as this board has a lot of very knowledgable people eager to contribute. I ran a separate set of 3 wires that came out at the spreader and a 4 wire set that came out at the masthead.
pigslo

Wayne25 01-09-2007 11:00 PM

Thanks again for your ideas. Hope to get more from the board. Its a deep well of knowledge learned the best way, by experience. Has anyone used the OGM mast head nav lights? https://secure.orcagreen.com/xcart/home.php?cat=249

hellosailor 01-09-2007 11:27 PM

Wayne-
For the RG/8U I'd suggest Ancor's expensive cable, which has a 96% shield and PVC dielectric material, which will absorb less water and distort less than the more common foams will. It is also fully tinned--which will make a difference since no matter how you seal the cable, moisture finds a way in.

In theory you support vertical coax by tying it off to a support every so many inches to spread the stress. Unless you have some kind of liner to secure your cable bundle to, that's probably not possible for you. Using a steel wire, or copperweld (copper over steel) and running that with your cable bundle, would allow you to tie them all together (maybe every foot or two) and use the steel cable to take the weight of the bundle.

To split out the steaming light, deck light, etc. you would need to measure the length to that point on the mast, then split open the outer jacket and extract those two wires, or split it open and splice in a "tee" if you can't pull them back down. You'd also need to splice in a "tee" to the ground wire in the bundle at that point. I'd make sure the splice was well sealed with butyl tape or silicone tape, and if there are any internal halyards, some anti-chafe over that.
The quality of your work (grommets, seals, splices) will pay off, so by all means go for the best.

Wayne25 01-10-2007 12:04 AM

Hellosailor:
I agree with your coax choice and have already purchased the coax. It is expensive, but very low signal loss.
Great idea about the vertical wire support! Expanding that idea, I could use a length of braded dacron line instead of wire supported from the masthead. That would allow me to insert the plastic tie straps through the braded line and around the coax and 5 conductor cable and it won't slip down. Also probably less weight than wire and no corroding or rusting. It would also allow me to extract the wires out of the jacket as you recommended and still have the support needed. Thanks for the great idea!

I'll need to remove the masthead and base aluminum castings from the mast to do this. Looks like stainless steel pop rivits used for fastening. Having not done this before, I assume I drill out the SS pope rivets and replace with new SS pop rivets when I'm done? Or is there a better way?

Wayne


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