Carbon mast shroud attachment?

Hi guys I have a cf groovy mast and I was wondering how you attach the shrouds and foreatay to the mast. I am a bit reluctant to just drill a hole and use a hook as I have done in the past with aluminium masts as I fear that the carbon may crack, splinter and break away. Any sugestions? Or am I just over thinking it? Thanks in advance.

With Carbon masts, I bend a small attachment, then lash it to the mast with kevlar thread and CA. If I dont have kevlar, unwaxed dental floss works as well. Then no holes in the carbon.

I have drilled holes and epoxied a ss hook that I tied shrouds to, and never had any issues. However, I started doing as John, and lashing a fitting to the mast so there was no hole. If you are using a groovy mast, this would not work because of the sail groove.

Drill holes and make sure you epoxy the fitting into the hole and seal the edges of the carbon with the epoxy so as not to create a point for a split to start. Remember that most all “real” boat carbon masts have holes molded in them to accept tangs for shrouds.

I too use the lashing technique as well, the less holes, the better… I prefer carbon tow or loops of dyneema secured again with CA or epoxy. My latest technique does involve drilling 3mm holes through the rig, then bond a 3mm Carbon rod into the holes. The rod is continuous and passes from one side to the other. Once cured - Trim the rod leaving approx 2mm excess protruding from each side. With small diamond files I shape a groove into the top of the rod. The loop in the end of the shroud locates snugly into the groove and your set. No way are you going to bust these fittings, nothing to debond, and the rig tube remains sound.

Just an addition, if you are drilling holes in Carbon be careful that you don’t delaminate the fibres. All small holes are best done using Diamond burrs in a Dremel tool or similar. Regular Twist drills do have a habit of ‘chewing up’ the laminate.

Thanks, I like the carbon rod system. do you also use a carbon rod for the foreatay? Or do you form a loop around the front of the mast between the two to attach the foreatay?

If the forestay height is right using the shroud location then a loop between them is perfect… If not then, you might have to place another in the mast and use the loop on that.
Nowadays just about everything you can think of on modern racing yachts are attached using soft loops, making shackles, terminations & bottle screws all history.
A well designed system using soft loops places much less point loading than with more traditional methods for considerable weight saving.

Hi Jim
any pictures to show ?

OR, wrap the carbon with masking tape where you want the hole. Then drill through the masking tape and carbon. Remove masking tape. You have a nice clean hole.

Just be careful removing the tape… Seen this done and seen it fail when the tape pulls Uni strands away with it.

I should have said Blue Painters Tape. I forgot that I haven’t had a roll of classic masking tape in my possession for many years :slight_smile:

Ihave seen guys use barrel swivels… like this…®-Bill-Fisher®-Heavy-Swivels/product/97312/-1448812 similar to what AC did with the carbon rod. drill through the mast, epoxy in the swivel…presto.

On most R/C boats I have seen the shrouds and backstay are made from thin wire,fishing trace I think. With the ready availability of spectra fishing line is there any reason that this can not be used for the same purpose. post #7 above indicates that soft fittings and attachments are used on the real thing maybe this can be done on the R/Cs. I can recall seeing an article somewhere that suggested wire had “local stiffness” not something I have had experience with for a few years but maybe is a reason for using wire.
Any comments?

This is how we attach the shrouds & headstay on our 6’ ACC boat. Basically it’s a T fitting made by hand.


you got a diagram of what the “t” look like does the bottom of the T come out for the forestay and the top comes out for the shroud on each side? and the $25000question. is it easily fixed or rethreaded in case of breakage?

on my current vic I did something similar to what you have showing. and if I break a shroud…Its not an easy repair.

but I just got some new spars and I’m going to make a new rig. not sure how I’m going to rig it…

Sorry no drawing. The shrouds & headstay are held in the same way. The t fitting is a small carbon rod, they are fed in through the top. In the event of a failure you can pull new shrouds in the same way but, it is tricky…
We’ve sailed the 6 footer (with 18lbs of ballast) in heavy winds (20 knots plus) and had no failures with this method over the past year.

so the carbon rod forms the top of the T and the forestay/shrouds make the bottom of the T as they come out of the hole drilled in the mast… Nifty…and yes it could be a bear to do a replacement pondside…

I use 30lb braided stainless for my ec12, 3 shrouds each side, adn then enter the side of the mast and dead man at the bottom of the mast crane. So if one breaks I have to feed a new one to the mast crane which just pulls out.

I drilled holes in my CF mast for my Vic I am going to use the same method I used on my ec12, and dead man them to the bottom of the crane…

for a minor twist, I am going use one line for both shrouds. the vic mast is plenty stiff so I don’t need much in the way of support to keep it straight, only support to keep it upright.

so the line 65lb spider wire. one end will be deadmaned to the bottom of the crane, passed through the upper shroud hole, down to the deck then continuing back to the lower shroud hole and back to the crane…to be knotted at the crane…

this way I will get the mast support over two points. and only one turnbuckle on each side. to save a few grams…

the only downfall is that if I loose a shroud, on one side, I loose both of them…and the mast falls over…