The Offshore Voyaging Reference Site

Carbon Fiber Mast, Costs and Benefits

In the last post I explained why we replaced our old aluminium mast. This post gets to the real meat: How much did carbon fibre cost? And what did we get for that money?

The new mast, excluding some new rigging, cost about US$55,000, as against an aluminum replacement mast, which would have cost about $30,000; a lot of money to us, particularly since it was capital we were spending that came from the sale of our house.


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Alex

I’m confused… was the new mast 55k or 25k?

Thanks!

Michael

Hi John,

Any data on how long an aluminum rig will last? Ours is 30 years old and we are on the fence about just sleeving the area near the vang attachment that is cracked and re painting or maybe going with a carbon rig. It’s a lot of money to be tossing around when the diffemce could be a few years more crusing or the rig not holding up.

Regards,

Mike R

Stein Varjord

I’d just like to support every word John says here, and throw in my 5 cents, or some. 🙂 I’ve mostly had my mast fracture problems on utterly extreme racing rigs. They are not directly comparable, of course, but they do tell you what works, and more frequently, what doesn’t. 🙂 What I’ll say, will to some extent repeat what John says, with some variations. I do that to keep the explanations complete.

First, when there are cracks in a mast tube, not only is the crack itself a weakness, but stuff has happened with the metal. Probably that whole part of the tube is quite brittle from fatigue loads. Making that “as good as new” is not possible, but it’s possible to make it work. A rather long insert that follows most of the inside of the tube is the main element. I’d say in a spot like that, I’d use a piece at least 1 metre/3 foot long. Preferably more. You probably have to make the insert from a piece of the same profile, cut off the rear end (with the sail track) and split it in the front. Use a file to round off the edges a bit. Makes the job easier. Do one side of the mast at a time. Spread some rather thick putty on the insert that will make the insert support the tube well. Epoxy is a good base that doesn’t get too brittle with time.

When the insert is in the right spot, have some means of pushing it hard towards the tube. I have found that threads in alu tend to corrode, so I don’t trust screws. I prefer “monel” steel pop rivets. Do NOT use aluminium rivets. Way too weak compressive force. Use the largest type, 6,4 mm. Make sure they are long enough. It’s smart to have two different lengths. You need a serious riveting tool. The amateur stuff won’t last the whole job. The hardening of the grip teeth isn’t good enough.

Put the first hole where the insert is already tight onto the tube. Gradually work your way out from that spot. Drill, rivet, drill rivet. This will use the rivet tension to pull the insert hard towards the mast tube. The pattern should be so that you try to avoid the perforated paper effect. Distance between rivets maybe 10 cm/4 inches, but that will vary with mast dimensions, metal thickness. There will be a lot of rivets! When finished, remember to hammer out the nail head from each rivet. Otherwise it will rust and damage the rivet.

An outside patch where the spot loads occur (like the vang attachment) will not increase the mast stiffness, but will spread the spot load so the mast can cope better. The patch doesn’t need to be very big. It also needs putty to make the mechanical contact good.

If my description didn’t already make it obvious, this is quite a lot of work with no guarantee for everlasting happiness. My advice would normally be: Get a new mast tube, but if that’s too expensive, this fix is something you can do yourself and it probably, but not certainly, will keep you sailing for a long time.

Michael

Hi John,

Thanks for the advice. The previous owner of the boat had made a new vang attachment years ago and the engineering was off causing stress cracks. Turns out the attachment/pivot pin was too far from the rig allowing for more leverage than was ever anticipated.

On the repair. We feel our rigger will be able to do a fine job. What we don’t like is spending half of what a new rig would cost on the refit of the old one. Cheap route is to go with the old but as you know that decision could be the expensive one in a few years.

Regards,

Michael

Pete Rasmussen

Hi John,
I enjoy your website and have learnt a lot of very useful stuff.
I wonder if you have tried hoisting a bag of sand or some weight to ease the jerky motion mentioned in windless conditions?
I’ve reduced my halyards from 12 mm to 8mm and noticed a difference and this is on an 10 ton ferro double ender!
Thanks for the effort to make this site such a great read.
Pete.

Dustin Doyle

Lifting a rubber coated weight to the top of the mast with a T slot attachment that goes into the main sail’s track should work, you can store it in the bilge area when not in use.

You could even make a fiberglass anchor attachment that would put the anchor into the main sail’s track, keep it from moving around, and protect the mast from scratches, and lift that as high as needed.

Greg

Hi. A novice here. I’m shopping for my first boat to refit on the hard for a few years. I’ve found a cat with a Aero Rig manufactured by Carbonspar. I’ve never seen this before (which is why I happened upon your site). Any feed back on this product? I see that you mention that cycling loads are the best indicator of wear, for any material. Any idea how much longer a carbon product will last over aluminum?

Thanks, Greg

RDE

Hi Greg,
If you are thinking of a catamaran as a first boat, give my friend Kurt Hughes a call and pick his brain before you make that leap. http://www.multihulldesigns.com/

And if the aero rig cat that you are looking at is the one for sale south of Seattle that has had several million poured into it and never launched, you might want to invest in a pair of NIKE’s running shoes instead.

Stein Varjord

This is way too late for any advice on buying this specific boat. Also, I’ve never actually sailed an Aerorig. Still I have some comments on it.

I’m a multihull fanatic and loves the unconventional too, so I should like it, but I must say I think the Aerorig is a misunderstood solution to the wrong problem, and especially so if put on a multihull.

It’s great to be able to depower at any angle of sail. It’s also great to have the rig balanced so sheet loads are low. The aerorig has both, but the lack of supporting stays and shrouds mean the rig is ridiculously heavy, expensive and still very soft. This means it’s impossible to get a good and stable sail shape.

The claim for superior efficiency, is mostly quite significantly the opposite. The much narrower slot between main and jib means serious loss of efficiency. Downwind this is better, but it seems much of the thought behind this rig is based on a misunderstanding of aerodynamics combined with overconfidence in carbon fibre, which is an amazing material, but not magic.