Pulling Cables Through Ducts.

DJE

DJE

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Just started replacing all the electronics on the boat and in a few places I need to pull out an old cable and pull in a new one. I have ordered some small cable socks to attach the new cable to the draw cord but first I have to pull the old cable out and the draw cord in. So what is the best way to attach the draw cord to the end of the old cable. I thought about using a cable sock but I don't think that would work as I would be pulling it backwards and if it snagged it could slip off the cable. My current plan is to open up the end of the cable twist the draw cord up with the cable cores then stitch and whip it closed again. Does anybody have a better method?

I want to use a draw cord and cable sock as the new cables will be NMEA 2000 with plugs on the end. I've tried taping the two cable ends together in the past with limited success.
 
Whooahh this is going to be a long thread (pun intended) there are at least 3 times as many methods as there are people that do this.
So, heres mine:
Lay the draw wire along side the cable, both "facing" the same way, then 3 running half hitches of the draw wire around the cable, tape the loose end of the draw wire to the cable, if its going to be a tricky one then a minimal cone made by the tape will help. Washing up liquid will really help the tight ones.

edit add:
When you have to have plugs attached then a cardboard cone works a treat. Corrugated is favourite, but cereal box will do fine for smaller ones.
 
When running new cables through longish and not very straight tubular ducts I found the best tool was a long length of the white-coated spring 'curtain wire' used for holding up net curtains. with a Biro cap taped to the end to give a small "nose cone". Then pulled through long NMEA2000 plugged cable with plug neatly taped to other end.
 
Also, tie a reasonably strong thread to the mousing line - if it comes disconnected from the cable, you will still be able to draw the mousing line back through the duct to have another go at it.
 
jwilson said:
When running new cables through longish and not very straight tubular ducts I found the best tool was a long length of the white-coated spring 'curtain wire' used for holding up net curtains. with a Biro cap taped to the end to give a small "nose cone". Then pulled through long NMEA2000 plugged cable with plug neatly taped to other end.
Click to expand...

The professional equivalent to this is a set of mousing rods - thin, stiff fibreglass rods about a yard long with metal caps that can screw together to make up the length you need. You can buy them from electrical equipment vendors like CEF. They come with a selection of ends including a bullet and hooks - avoid using the hook - it can get caught on something inside the conduit and become almost impossible to remove.
 
DJE said:
Just started replacing all the electronics on the boat and in a few places I need to pull out an old cable and pull in a new one. I have ordered some small cable socks to attach the new cable to the draw cord but first I have to pull the old cable out and the draw cord in. So what is the best way to attach the draw cord to the end of the old cable. I thought about using a cable sock but I don't think that would work as I would be pulling it backwards and if it snagged it could slip off the cable. My current plan is to open up the end of the cable twist the draw cord up with the cable cores then stitch and whip it closed again. Does anybody have a better method?

I want to use a draw cord and cable sock as the new cables will be NMEA 2000 with plugs on the end. I've tried taping the two cable ends together in the past with limited success.
Click to expand...

many ways to do it, if the cable had some decent size cores in it my preference would be to strip back the insulation on the old cable but don't remove it, solder all the cores together (neatly is the key here) then slip the cables back into the slit insulation and put a decent length of heat shrink over the top, this clamps it all together (this is assuming its flex)

never failed me in the past

something like this (but soldered not crimped) & neater in the last steps so the overall diameter is smooth and always constant

P7379-SP-2-1.png
 
Last edited:
I fitted my boat with ducts formed from 1" plastic plumbing tube. I ran half a dozen mousing lines through the pipe before fitting and it's been a doddle replacing wires ever since. I couldn't solder an old wire to a new one as the corrosion had gone too far up the wire. This has proved less of a problem with the replacement cables in the pipe as drips don't fall on them anymore.

I tape a replacement mousing line to the new cable so there's always a mousing line when I need one. Needless to say the pipes are straight.

I did this on a friend's boat, too. he wanted an access about 3' from one end for a bunch of wires to his nav station which was athwartship. I glued a tee piece on the longer side and we ran mousing lines through that as well as through to the forward cabin. He push-fitted a short length of conduit into the centre of the tee, and has a neat cable bundle in the centre of his nav station.
 
This is my preferred method when replacing wiring, solder old to new, and pull through, heat shrink and good solder joints, never had a cable fail pulling through.

Good luck!

Cactus Sailing said:
many ways to do it, if the cable had some decent size cores in it my preference would be to strip back the insulation on the old cable but don't remove it, solder all the cores together (neatly is the key here) then slip the cables back into the slit insulation and put a decent length of heat shrink over the top, this clamps it all together (this is assuming its flex)

never failed me in the past

something like this (but soldered not crimped) & neater in the last steps so the overall diameter is smooth and always constant

P7379-SP-2-1.png
Click to expand...
 
RobBradley said:
This is my preferred method when replacing wiring, solder old to new, and pull through, heat shrink and good solder joints, never had a cable fail pulling through. !
Click to expand...

I have used this solder together and heat shrink technique successfully to thread a new navigation light wire through the pulpit.
However, currently trying to do the other side and there was more friction. Although being very careful the old wire is very thin and seems to have gone stretchy. I fear the copper bit of the old wire has failed and just on the rubber insulation now.
So caution with thin wires that are not strong. Think I am going to have to try thin drawstring next
 
maby said:
Also, tie a reasonably strong thread to the mousing line - if it comes disconnected from the cable, you will still be able to draw the mousing line back through the duct to have another go at it.
Click to expand...

What for ???-- You would be able to pull the mousing line back any way. Why would you need a line to pull that back ???
You are making this up!!!
 
jwilson said:
When running new cables through longish and not very straight tubular ducts I found the best tool was a long length of the white-coated spring 'curtain wire' used for holding up net curtains. with a Biro cap taped to the end to give a small "nose cone". Then pulled through long NMEA2000 plugged cable with plug neatly taped to other end.
Click to expand...

But the OP said that he had the original wiring. Why would he need to nick the wife's curtain wires.
 
Cactus Sailing said:
many ways to do it, if the cable had some decent size cores in it my preference would be to strip back the insulation on the old cable but don't remove it, solder all the cores together (neatly is the key here) then slip the cables back into the slit insulation and put a decent length of heat shrink over the top, this clamps it all together (this is assuming its flex)

never failed me in the past

something like this (but soldered not crimped) & neater in the last steps so the overall diameter is smooth and always constant

P7379-SP-2-1.png
Click to expand...

Very interested to know how you get the heat shrink on after soldering the wires ... :)
 
N2K plugs though small holes are a pain in the ass so I use field terminations which can be put on after the cable has been pulled.

Otherwise, generally with normal endless cables... stick on well to old cable and pull. Then swear if it comes off and start again.

Some of the big posh boats I work on get a bit of 3mm dyneema rope pulled it as a draw string. If the conduit is fairly full or is convoluted inside, then it'll be a nightmare but hand cleaner gel on the in and out can help a lot too.
 
dunedin said:
+1. https://www.amazon.co.uk/dp/B00WK82...t=&hvlocphy=9046896&hvtargid=pla-421592040690

Also used for threading new under deck reefing line and rethreading In boom outhaul pulley system (though used parts from 2 sets due to length needed for 45 foot boat)
Click to expand...

I have used those for many applications especially to get wipes into the bilge and retrieve them but when I wanted to pull through wiring through any curved surface they snapped and they are quite brittle without much flexibility
 
Stemar said:
Very interested to know how you get the heat shrink on after soldering the wires ... :)
Click to expand...

i thought the same, was just a google image to try and explain better, theres some strange image flipping going off between the cables too, its like spot the difference.
 
When I did my N2K network I sacrificed a male and female terminator resistors by drilling them and tying a a loop of strong thin line through them. I could then select which ever one was appropriate and fit it to the cable end to be pullled then attach the mouse line to the loop. I actually used an electricians fish tape (thin sprung steel in a cassete) for new routings where old cables couldn’t be used as mouse lines.
 
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