Ho big a hole can I drill at the base of a mast?

[Malish]

I've a Kemp mast dating from about 1972. Wiring running up to the mast head enters at the base throug a series of 3 or 4 small holes drilled as required by previous owners. The clattering of the wiring against the inside of the mast is an irritation that I would like to remove using un-cut cable ties at regular intervals. None of the holes at the base of the mast are big enough to take the bundle of wires + ties and hence I need to enlarge one of the holes. My question is how big a circular hole can I safely create and where is best to put it - facing forward or to the side? is it worth reinforcing the area with a riveted stainless steel ring? I have a hunch that the size I am likely to need is about 2.5 cm diameter. The mast is deck stepped, the foot will not come off (screws well corroded) and I would say the mast has a fairly thick aluminium section, at least given the comments about its weight that the yard hands make every time the mast is unshipped for winter. Boat is a Rival 32

 

[Strathglass]

If I were you, I would flatten out the round bundle of wires then-

I would put a vertical slot (12 - 15mm wide about 80mm long) in the side of the mastabove the foot, It should be of a similar size to the slots for passing the running rigging through through the mast.

Then fit a stainless or plastic fairlead in the slot to reduce the chaff on the wires.

There should be no holes all the way round the mast within at least 2" from the top or bottom of the slot position.

Iain

 

[PeterGibbs]

I take it your mast does not have a dedicated channel running down the inside to accommodate wire runs? I had this on my old Fulmar, and,yes, the wires do slap about a bit inside.

I never solved it - even pulling all the wires out and taping them together at intervals to make a stiffer bundle. Your thinking is that cable tie tails will brace against the wall and silence them? Could work.

Holes in masts is a squishy subject. But I do not hear of masts collapsing because radar cables (about 20mm) are run in through a frontal hole - not a problem on mine. So 25mm? Probably ok. Instinctively I suggest a hole in the side and maybe 10-15 cm up from the base. No doubt you will keep the hole as small as possible.

PWG

 

[oldsaltoz]

Can you feed the wire in from the top, avoiding the need for a larger hole at the base?

Avagoodweekend......

 

[homa]

Personally I would have another look at removing the mast foot.

Did this on my mast (1979 vintage) by drilling out the rivets. And tapping off the foot.

Allowed me easy access into the mast. This will enable you to easily run cable and ties up inside the mast.

Good luck
Homa

 

[PBooth]

Hi, the cable tie trick does work, on a previous boat I used small ties ( about 3" long) in groups of 3 so they held the wires away from the mast walls. You only need a small clearance round the wire to feed it and the cable-ties into the mast, you could do your cables individually to save on any new holes. I am assuming that you have external halyards.

Peter

 

[MM5AHO]

Identical boat and mast here. Best is (as said above) get the mast footing off. Those corroded screws need sorting anyway.
Our holes are about 10mm dia, two off take VHF coax and nav lights cables. Both grommeted.
An alternative (not so good) to the cable tie method is to use silican glue. Smear heaps of the cable as you feed it in, and it will surely stick to something. Sometimes the inside of the mast! What doesn't stick becomes a rubber shroud on the cable that doesn't make a noise when it slaps inside.

 

[William_H]

First choice would be to remove the base. However you may have to cut the bottom off the mast to open the metal from around the base. You could lse 2 inches of mast. You may need the base off for other reasons at anothe rtime so it won't be completely wasted. Use lots of Duralac when refitting.

However it would be far better if you can avoid big holes in the base.
I had a mast on 21ft trailer sailer where large holes had been cut for 2 turning blocks near the base. After some years of corrosion and replacing the blocks the holes got quite large like 25mm by 30 mm one on each side at the bottom. Later I found that the mast was starting to compress with folds in the existing metal so the mast shortened by about 1cm. I had it reinforced with an added sleeve.
Sadly that mast was later lost in an accident with a marker post. Now I just have slots up higher and well spaced (vertically) for halyards.

The moral of the story is you can weaken the mast with holes that are too big especially if they are at the same level. But then you will probably be OK. good luck olewill

 

[VicS]

[ QUOTE ]
you may have to cut the bottom off the mast to open the metal from around the base. You could lse 2 inches of mast.

[/ QUOTE ] Makes the standing rigging a bit slack!
/forums/images/graemlins/laugh.gif

 

[William_H]

Garn nobody would notice .....much olewill Have hacksaw will travel.

 

[Malish]

Thanks for all the responses - oldsaltoz's idea is elegantly simple (which I like a lot) the mast was coming down this winter anyway so a hole on the top plate seems the way to go.

 

[chasroberts]

If you can get easy access to the bundle then after cable tying them together wrap in foam water pipe insulation. You can pick this stuff up in metre lengths cheap as chips from B+Q etc. Avoids cables abraiding on the inside of the mast and as an added bonus - Hey Presto no more frapping.......