Getting a cable down the inside of mast?

Eeyore

Eeyore

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Joined
5 Oct 2007
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Location
Kudat, Malaysia
www.yachtrhumbdo.co.uk
Evenin’ all

I need to get a 12mm radar cable down the inside of the mast from a point just above the spreaders. Drilled a 12mm hole (biggest drill that the chuck can take) in the front of the mast and found that there is an aluminium conduit about 6mm from the front face of the mast, containing (I assume) cables for tricolour, vhf, wind instrument and steaming light. I don’t want to go to the expense of taking the mast down and wondered if anyone had any ideas/tips on how to ‘break into’ the conduit without damaging the wires contained within……and secondly, what would be the best way to enlarge the 12mm holes to maybe 14mm so that the cable can be passed through both mast and conduit?

Cheers.
 
Not sure how you'd get into the conduit to be honest. you MIGHT get away with a cordles drill on slow speed and a fairly blunt drill. If you can drill as small a hole as possible just close to where you need the big hole, youMIGHT be able to push something in to push the wires out of the way, but its very risky! In view of the cost of a mast and the hasle of redoing wires, I'd take it down, I'm afraid! You'd never be sure that you hadn't nicked the insulation on one or more of the internal wires.

As far as the 14mm hole is concerned, you can buy reduced shank drills (sometimes called "Blacksmith's drills"). Try a search. Pretty sure large B&Q sotres have a selection. That said, in a thin section like a mast, you'll get a sort-of triangular hole with rounded corners. If you can get a small enough holesaw that would be better. Also try a round file on the 12mm hole if the section's not too thick at that point.
 
Are you sure there will be room to fit the radar cable 12mm with all the other cables in the conduit? If not sure then it might be best to pass the cable down next to the conduit.
It might not be necessary certainly not desirable to open the hole up to 14mm. Almost certainly the cable will will exit the mast in an upward direction ie not at right angles to the mast. A steel rod or even cold chisel can be put into the hole then hit sideways with a hammer to bend the mast material in at the top of the hole out at the bottom to produce a smooth exit for the cable. A file can o-pen it up if you need a bigger hole.
good luck olewill
 
We used to use a windy (general purpose air tool) with a bit in it that was something a large engraving bit when we had to do this on aircraft - I guess a Dremel would be similar but smaller - you need a steady hand and a clear view.

Once you have small slot cut you can get a bent piece of wire or similar in and use this to hook cables out of the way. It's difficult to guarantee you haven't nicked a wire when you first break through though - it needs patience.
 
[ QUOTE ]
To do this job you should take the mast down
If you want it inside the mast that is.

[/ QUOTE ]
But from the way the OP describes it there will still be the problem of breaking into the conduit without damaging cables. May as well be done in situ without the extra cost and hassle of taking the mast down.
 
May I suggest that you forget about the conduit for the moment and take the Radar cable down the outside of the mast.. You can do this quite neatly with stick- on pads for cable clips and later when the mast is down , you can review the conduit situation.
I would also chat to a "mast man" because this will not be a new problem.
 
[ QUOTE ]
May I suggest that you forget about the conduit for the moment and take the Radar cable down the outside of the mast.. You can do this quite neatly with stick- on pads for cable clips and later when the mast is down , you can review the conduit situation.
I would also chat to a "mast man" because this will not be a new problem.

[/ QUOTE ]

What a good, and sensible, idea. Thinking outside the box, (or mast /forums/images/graemlins/smile.gif )
 
You can obtain cheap conical cutters which will fit your drill and can enlarge the hole to form a slot lengthways, or expand the diameter.

As already said I would forget about getting into the conduit for the present, too fraught with problems.
 
OK....thanks for the responses. I first looked at running the cable down the outside of the mast and dismissed it. Aluminium extrusion is difficult to get in Turkey and the material is very expensive. Running down adjacent to the conduit isn't possible because it's only 6mm from the front face of the mast. Raymarine have today been up the mast and looked into the 12mm hole - and they will drill into the conduit but with reservations about any subsequent damage (understandably). My remaining options are to a) drill a further hole around the side of the mast and behind the conduit, then drop the cable down and plate over the existing hole, or b) pay 500 quid to take down the mast, then completely rewire it! Why is nothing ever easy?
 
I did not reply earlier as your Q was about running the cable down inside the mast,

But you refer the possibility of running the cable down the mast on the outside.

I have done that, in a marine plastic conduit. Not very expensive in the UK, and so easy to install and remove when the radar might need dismounting.

Added benefit of not having a cable join in the radar cable.

If not available in Turkey, then presumably you can get it posted out from the UK.
 
Hi Eeyore and others,
I have to fit the Furuno 1623 randome and cable when I get to the boat in June.As radar is changing so rapidly to new types I feel the suggestion to fix the cable to the outside of the mast is best because the cable may soon be redundant anyway. Thought to use electrical snap front conduit and spray same silver and perhaps use a small self tapper at intervals to back up the adhesive in hot Med conditions.Still mulling over whether to just do the same with the deck section of the cable or to plunge beneath decks at foot of mast.I hope to mount the screen under the sprayhood for easier observation, but perhaps I should also consider mounting upside down from the deckhead at the chart table so as to be able to compare with chart display.What do others think (those with integrated screens may feel smug reading this!) my budget does not stretch to all the bells and whistles! good sailing to all
 
Depends when you last stepped the mast - not done in the last 5 years? Do it now - you can do all the other mast wiring/lights/VHF etc servicing jobs that should be done and never are and, if you are of so a mind, you can then fit steps up the mast - just a thought!!!
 
[ QUOTE ]
I did not reply earlier as your Q was about running the cable down inside the mast,

But you refer the possibility of running the cable down the mast on the outside.

[/ QUOTE ]

Sorry, that was just a response to an earlier reply. Previous threads on here have discussed running the cable down the outside and the impression I got from those was that it was both unsatisfactory and unsightly - hence my dismissal of that idea. Shipping ANYTHING from UK to Turkey is a logistic nightmare and hardly worth the effort for some plastic conduit - I've had a sail in Istanbul customs since January and neither I nor the sailmaker can get it released (it's to be destroyed now.....allegedly). I'm reluctant to step the mast just now because of insurance requirements later in the year, which may result in re-rigging for onward passage into the Red Sea.
However, I think I may just have to do that sooner rather than later!

PS Paulclan......mine is the Furuno 1623 too, so good luck with it.
 
I must admit my gut reaction is to go for fitting the ca\ble outside the mast if you dont want to take it down. Judging by most of the mast conduits I have seen there is little chance you will find it big enough to get your radar cable in and I suspect the chances of breakin in to it without damaging the cables in is very slim. As for enlarging the hole your best bet is a step drill, these give you 2mm increments in size and will get you up to abount 30mm. IN future you would be better to go for decent holesaws and buy extras as you find you need a new size, my collection is getting moderately comprehensive from 20mm up to 105mm, thought there are gaps some manufacturer will get me to fill.
 
I agree. We have the little JRC radar and the cable would definately not fit in the conduit. It runs down the leading edge of the mast in plastic conduit and makes for an easier job if we ever need to remove
 
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