NASA Marine Instruments

zoidberg

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Your wish is my.......

Hello. May I ask...?

I have 'inherited' an aged relative's project boat and with it a number of unused, unfitted NASA products - including the MeteoMan unit and the NMEA ( 3 wire ) masthead unit.

I'm now looking to install these and other products and my query relates to the power/data ( 3 wire ) cable. The mast is 'down' and faces a 100 mile journey, with the boat, to the sea and re-launch. I will mount the 'fragile' masthead unit after re-launch but want to run the cable down inside the mast, while it is here. That would necessitate cutting the cable near the unit and later rejoining it.

Would you have any recommendations for me regarding making such joins, bearing in mind that is likely to be at height?

Then:

Ideally it would be soldered back together and then each wire separately wrapped in self amalgamating tape. Failing that a terminal block would do it again sealing it afterwards.

I'd got that far myself, and was hoping for something a little more esoteric. I don't intend to attempt soldering, 30-odd feet up and suspended, slowly spinning, in a harness.
Instead, I reckon on using those adhesive-lined cable connectors with low-temp solder in the middle. Then I'll slide some heat-shrink tubing into place, on each of the three small wires, and warm that up until it compresses.. Then I'll slide a broader section of heatshrink tubing into place, covering all 3 now-sealed wires, and shrink that on.

Belt and braces.....
 

JumbleDuck

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Then I'll slide some heat-shrink tubing into place, on each of the three small wires, and warm that up until it compresses.. Then I'll slide a broader section of heatshrink tubing into place, covering all 3 now-sealed wires, and shrink that on.

Glue-lined heatshrink is your friend for such things. It is a lot more expensive but in every other respect the dog's danglies.
 

bbg

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Your wish is my.......



Then:



I'd got that far myself, and was hoping for something a little more esoteric. I don't intend to attempt soldering, 30-odd feet up and suspended, slowly spinning, in a harness.
Instead, I reckon on using those adhesive-lined cable connectors with low-temp solder in the middle. Then I'll slide some heat-shrink tubing into place, on each of the three small wires, and warm that up until it compresses.. Then I'll slide a broader section of heatshrink tubing into place, covering all 3 now-sealed wires, and shrink that on.

Belt and braces.....
Wouldn't it be easier to run a mouse line in the mast when it was down, then using that to pull the cable through from the top when it is up? Or even when it is down after the 100 mile journey? I would have thought that is a lot easier than trying to re-attach the cable at the top of the mast ...
 

Spirit (of Glenans)

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Wouldn't it be easier to run a mouse line in the mast when it was down, then using that to pull the cable through from the top when it is up? Or even when it is down after the 100 mile journey? I would have thought that is a lot easier than trying to re-attach the cable at the top of the mast ...

+1. Run two or three mouse lines while you are at it, in case you need one in future, to fit some other equipment at the masthead, or in the unlikely event of breaking a halyard.
 

zoidberg

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Wouldn't it be easier to run a mouse line in the mast when it was down, then using that to pull the cable through from the top when it is up? Or even when it is down after the 100 mile journey? I would have thought that is a lot easier than trying to re-attach the cable at the top of the mast ...

I agree with you, entirely. In fact, that's what I suggested I would do.

As for 'multiple mouse lines', I'd be tempted to rig some baggywrinkle on 'em..... ;)
 

bbg

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I agree with you, entirely. In fact, that's what I suggested I would do.

As for 'multiple mouse lines', I'd be tempted to rig some baggywrinkle on 'em..... ;)
Sorry, I misunderstood. I thought you said you wanted to run the cable down the mast and leave it in the mast during transport, then only re-attach the masthead unit when the mast was up.

My suggestion was to run the mouse line when the mast was down, and once the mast was up, use the mouse line to draw the cable down through the mast. So you never have to cut and re-attach the cable at the masthead.
 

zoidberg

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Yes, 'bbg', we're on the same page. No 'sarky' intended. Limitations of online comms again. Here, 'ave a smilie! :D

The mast is indeed 'down' and horizontal. I'm replacing all the cabling AND the now-tired mousey lines I'd run with shiny new stuff, spending all my pocket money on boaty bits. I'll hope to rig the several cables down the mast, all ready for connection at/after launch, for I don't want to risk my shiny new 'Salty John' antenna!

As for the 'baggywrinkle' - that was an attempt at feeble humour. Would you believe I was 'stonished to see just that on the angled backstays of a quite small trimaran at Restronguet Creek/Pandora Inn some years ago....? Made sense, of course, once one had considered the expensive Mylar mainsail.
 

zoidberg

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Yes, Steve. I'm wondering how I might achieve that effect. I may be able to 'capture' the group of cables at different heights as I haul them up, fishing through an 'ole and wrapping cable ties around which will effect a 'star pattern'. Or I might just try to live with the hollow ringing while bobbing about on't mooring at night. Just nearby is the RN MoDPol dogs' compound, and it's quite likely the mast noise will keep them awake - then they'll keep everyone else awake, for a mile around.....:rolleyes:
 

bbg

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Yes, 'bbg', we're on the same page. No 'sarky' intended. Limitations of online comms again. Here, 'ave a smilie! :D

The mast is indeed 'down' and horizontal. I'm replacing all the cabling AND the now-tired mousey lines I'd run with shiny new stuff, spending all my pocket money on boaty bits. I'll hope to rig the several cables down the mast, all ready for connection at/after launch, for I don't want to risk my shiny new 'Salty John' antenna!

As for the 'baggywrinkle' - that was an attempt at feeble humour. Would you believe I was 'stonished to see just that on the angled backstays of a quite small trimaran at Restronguet Creek/Pandora Inn some years ago....? Made sense, of course, once one had considered the expensive Mylar mainsail.
I think we are still talking at cross-purposes. I don't know why you would run the cabling inside the mast now, if it means you have to cut the cable at the masthead and try to reattach it while working at the masthead while the mast is up.

It seems much easier NOT to cut the cable, but to have a mouse line for that cable. Then, when the mast is up, you use the mouse line to draw the cable down the mast. All you need to do at the masthead is the much less fiddly job of feeding the cable. Not making an electrical connection in a place that it is difficult to work and that also introduces another point of failure in the wiring.

When I transported my mast, there was enough play in the cable that allowed me to remove the antenna from its mount and fold it back against the mast, where I taped it in place.
 

zoidberg

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OK, 'bbg', I get it now, thanks. I'll likely do that. I'd been fixated on the avoidable hassles when clamped at the top of the mast, swinging around violently as the Plymouth RMs charge past in streams in their training landing craft.

There is an argument for fitting the VHF antenna onto the pushpit, and I've just remembered it..... :rolleyes:
 
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