Cutting holes in the mast!

Wunja

Wunja

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The masthead on my boat has 4 sheaves. The haylards run right through the mast head from front to back and down the outside of the mast.
I am considering running the halyards inside the mast, to free up two of the sheaves for storm sail and uphaul.

The mast is 30+ years old. 10 meters in length and mounted in a tabernacle.

I have found mast exit plates that create a smooth slot allowing the halyard to move from inside the mast, continuing to the turning block at the foot of the mast.

1. Is this a sensible thing to do? I know I could have blocks shackled to the mast head (as per the current uphaul) but seems like having a lot of string flapping against the mast.

2. Any advice on positioning the slots and cutting them to prevent weakening the mast?

Many thanks for your thoughts.
 
Wunja said:
2. Any advice on positioning the slots and cutting them to prevent weakening the mast?
QUOTE]

Don't know about positioning but I found a router with a metal cutting bit extremely effective at providing a neat result.
I would have a look at similar masts in marinas to get ideas for positioning.
Click to expand...
 
It's extremely difficult to give good advice on this sort of thing without laying hands and eyes on it.

Keep the slot as norrow as practicable, look for a fitting that will provide local support at that point have rounded ends to the hole not even a fraction too long for the support fitting.

Use monel rivets.

Show it to rigger before you make any holes.

Good luck.:)
 
Hi Vince

I've got a rigger coming to see me next Wednesday - shall I ask him? What make mast is it?

I would have thought that if possible the two slots should not be in line either horizontally or vertically and if they are opposite sides of the mast then I shouldn't think this would weaken the mast structure.
 
Hi Roger,

If you could please.

There are no makers plates on the mast. It could be a Proctor. Probably no help, but its anodized gold.
 
Halyard exit holes in mast

I have cut exit holes in the sides of my mast. A said they are staggered in height above the deck and in vertical line. I have 3. I made the holes by drilling with a 12mm drill bit. Once the drill went through I angles the drill and bit down to cut the hole at an angle similar to what the rope exits at. I then go a peice of steel rod of similar size put it in the hole and bashed the bottom so bending the mast material a little bottom in top out. With a bit of smoothing with a round file the hole is reasonably gentle on ropes.
My main halyard has a wire rope with rope tail. It tended to cut into the top of the hole. So I fitted a small piece of Stainless steel plate across the top to take the wear.

The location of the holes is a compromise. Keep them as low as possible to avoid weakening the mast. Mid way between spreaders and bottom is the worst place. Close to the bottom no problem. On the other hand up higher gives less direction change for the halyard as it goes to the turning block.
Also up higher means that you can pull the halyard from standing near the mast base. This is done with spin halyards where a crew person can grasp the halyard above his head and pull it down with much speed and power. In this case a clutch is fitted just below exit hole. After spin is up the halyard is pulled through to the normal place on cabin top at cockpit for release from there.
My spin halyard is too low for that unfortunately. Spin halyard about 80cms above deck. Jib halyard about 60cms above deck. Main on the other side about 50 cms above deck all on a 27ft mast 21ft boat.
Good luck olewill
 
Think of an ally mast like a solid wooden one, longitudinal shakes are no problem, damage across the mast is.

Therefore never have the slots close together but keep them at least 400mm apart longitudinally.

As you don't want the halyards touching internally, keep them apart slightly more than the diameter of the halyard radially, giving an easy lead to the block or winch.
 
I have done exactly what you are talking about, and cut slots for all my halyards including the spinnaker.

I went to the mast manufacturer beforehand and got them to provide a drawing of the location, and they also provided small stainless bump plates to put inside theslot at the top, and outside the slot at the bottom, so that the halyard wore on these instead of extending the slot!.

Cost - minimal

benefit - reduction in worry that I was weakening the mast!
 
Wunja said:
Talulah - when using the router, did you have a template or use it free hand. If a template, how did you attach it to the mast?
Click to expand...

I did it freehand. I have had quite a bit of practice in the past.
Just take it slow and make sure the router wants to flick into the waste area not into the bit you want to keep.
 
When I did mine, I drilled at the top and bottom of the slot, with a drill the same size as the required final slot size. I then used a jigsaw to cut out the unwanted metal inbetween, finishing with a decent file in order to remove any sharp edges (and any slight errors!)

Remembering to tape either side of the slot in order to prevent any scratches to the anodising.
 
Vince (Wunja) - I spoke to the well regarded rigger Dave Nicholls today about creating mast slots.

Slots on the same side of the mast should be half a metre apart vertically and at least 5 cm apart horizontally. Looking at my mast there is a seam down the side - the slots should be on different sides of that seam.

If you want to put slots on both sides of the mast then they should be similarly spaced but a quarter of a metre horizontally from the slots on the other side.

PM me if you need a diagram.
 
MoodySabre said:
Vince (Wunja) - I spoke to the well regarded rigger Dave Nicholls today about creating mast slots.

Slots on the same side of the mast should be half a metre apart vertically and at least 5 cm apart horizontally. Looking at my mast there is a seam down the side - the slots should be on different sides of that seam.

If you want to put slots on both sides of the mast then they should be similarly spaced but a quarter of a metre horizontally from the slots on the other side.

PM me if you need a diagram.
Click to expand...

Mr D Nicholls was entrusted with cutting the extra holes in Full Circle for the extra Spinnaker & Genoa halyards, and for the fittings for the removeable forestay. He speaks wisely.
Fittings are available which will fit the slot in the mast nice and shiny stainless rivetted on.
Important thing is to ensure the holes are smoothly radiussed, and leave no stress raiser edges which might propagate cracks. Also remember to protect the exposed aluminium (after you have removed the anodising) with Duralc or similar coating.
 
Thanks to everyone for all the input.

Having had a long look at the mast at the weekend, I have decided that this isn't going to happen.

Apart from not being brave enough to hack holes in the mast, it is almost certain that the internally running halyards would chaff against the rivet ends of the various cleats, winches, bullseyes and other gubbins that has been attached to the mast.

Thanks again.
 
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