Drilling a hole in a carbon fibre mast.

[johnMi 2]

I have a querie about drilling a 5mm hole in a carbon fibre mast.

The reason being is I need to have a mast raising pole that fits on the front of the mast about a metre from the mast step ( Trailable boat). I can use velcro to support it on the mast, but this will not stop it from swinging to the side. By inserting a pin fitted to the raising pole into a hole in the mast will prevent the swinging.

But

1. Will that 5mm hole compromise the strength to an unacceptable level

2. What is the best method of drilling carbon fibre, ( Fast, Slow )

3. Should I reinforce around the hole with extra carbon Fibre

4. Does anyone else have another better idea of securing the raising pole

[Kiteroa 8]

1 - Any hole in a carbon mast that was not allowed for with additional patching will compromise strength in that area.

 

2 - Try to keep it cool while drilling. So sharp drill and light pressure.

 

3 - Yes. To what extent I can't say. You need to know what laminate the tube was made up of to make that call.

 

4 - Try and bond something to the mast rather than drilling holes.

[RushMan 31]

Drilling holes sounds like a recipe for disaster

 

Have you had a look at other systems?

 

I like the system on Hurts, it controls the mast with removable stays, might be worth having a chat with Dean.

[johnMi 2]

Rushman, I also have removable stays, but they only control the mast.

On PE I was able to support the mast raising pole by lines from the end of the pole back to the deck anchors that are on the centreline of both the mast pivot and the raising pole pivot.

On Sledge, the raising pole pivot is different to the mast, so I can't support the same way. (The lines need to alter as the mast goes up)

I will not drill holes after the comments. I may glue some brackets on the mast to stop the pole from slipping.

So

Next question.

The mast is white, so it must be painted.

I guess I need to sand off the paint, then what would be the best way to fix the bracket. 2 pot glue?

[Ed 143]

If it's not going to see a huge amount of load, just glue onto the sanded paint

[Hurts 6]

Hi John - My mast raising pole has three stays to support it 1. goes about 3m up the mast and 2 side ones go down to the pivot points (same place as the mast supporting stays attach to) - my mast raising pole comes out pretty much from the base of the mast (or close to it) so the lines don't need adjusting as it pivots around and mast goes up and down. I've hunted out the F82 designs/specs and as standard the pole should be the same as mine, though the spec doesn't specify side ropes - JT may have added them in for me after he'd had some experience with Kant Know. I think I actually have an F9 system not an F82 system. I've never had any issues with mast/stay stability thankfully but I don't do it very frequently and seek out nice days.

 

If you could lower the point at which the mast raising pole connects then I think you could use the same pivot points like mine does and get sideways stability, hard to think of any other nice way to do it.

 

It's possible Jon moved the pole up to accommodate the mega centerboard, otherwise the pole will hit it when mast up (ay Rohan) - I now have to take my centerboard out entirely and store it in the cabin for the few times I actually drop the rig and take her places.

 

PM me if you want me to scan and send mast base and pole specs and plans.

[RushMan 31]

Haha Dean... When you asked for a hand to raise the mast I didn't think it would involve lifting Hurts off the trailer and cutting a hole in the trailer.

 

We didn't even have to use the number 8 wire either!

[johnMi 2]

Hi Dean

Thanks for the tips

Yes, if the pole is in line with the pivot points all is well, (PE was like this) but unfortunately it's not.

That's not my only issue. When Jon made the mast canting, he had to change things, but also I believe the whole mast step etc is different to normal as the step is fully Carbon Fibre. Usuallly I believe the ball of the mast comes away from the socket. On mine, the ball and socket stay together and the whole mast step rises off the deck. However, the ball moves maybe 2-3 mm away from the socket before it is restrained, just enough to mis-align the brackets on the deck. I have to let the mast come back to take up that 2-3 mm before tightening the temporary support stays.

I have been thinking of using the running backstays as well as the temporary stays, while lowering the mast, the angles/length may be more forgiving. I'm also thinking of lengthening the mast raising pole another metre as well. I did that on PE, made a hell of a difference on the tensions on the initial lift.

As I intend to travel around with the boat (want to go cruising all the Sth Island Lakes for 6 months) I need to get it to the point I can lower and raise easily by myself

Regards

John

[Hurts 6]

The standard F82 mast base does pivot with the mast (the ball socket doesn't come out, the base moves with it as you describe) - it's a bit strange and possibly not a great idea - Eamon is probably the guy who can make the most sense on this subject as he used to raise and lower his mast single-handed (or Jon). It seems my only experience with with the F9 setup which does to work well - still the whole process gives me the willies and I've never tried to do it single handed.

[johnMi 2]

Dean,

One way I can minimise the 2-3ml is to rebuild the swivel joint. It is a stainless ball, but the socket it sits into (some sort of plastic) has basically worn away. Do you know what material is best used for this?