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49er - new style mast


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Hi,

 

monday i bought a 2006 OV 49er. It comes with 2 masts, a perfect new style and a very fine old style. But i've only new style sails (main, jib and spi). For a first test on water i will try the old style mast, but i'm not sure that the newstyle sails a right for the old mast....

Thanks for your help :-)

Michael

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Jib and spi work on the old style rig. The main however is completely incompatible and even if you could somehow put it on you shouldn't. Probably won't break the mast, but the old alloy/composite mast is not built for those loads or cut of the sail.

Start with the new rig right away. It is somewhat easier to handle and more fun to sail. Why do you want to try the old one?

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Actually, even the Spin wont work on the old style mast, there is another 140mm of hoist on the "all carbon" mast, so the spin will end up overly flat with the luff rolled out.

Upside, is the all carbon mast appears not to have a used by date, so saving it, makes little sense.

                            jB

 

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I was not aware that this is an issue with the spinnakers. Thought the halyard stopper was there to account for that difference. 

Or is that something that has changed with the new spinnaker version? I am really out of the loop with recent developements. 

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We intially placed the stopper about 140mm down the mast so the old spins would work.

But when we did the new spinns, we moved the stopper right up so it part of the mast head fitting.

With the new CST mast that is being rolled out now, the stopper is incorporated into the mast head fitting.

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On 9/26/2020 at 9:43 AM, JulianB said:

Actually, even the Spin wont work on the old style mast, there is another 140mm of hoist on the "all carbon" mast, so the spin will end up overly flat with the luff rolled out.

Upside, is the all carbon mast appears not to have a used by date, so saving it, makes little sense.

                            jB

 

Hi Julian

A quick question following on from this.

What the view on leaving the new mast up and in the weather between sailing days?

I've read your stuff about ensuring there's air flow through it to avoid cooking it.

I'm more asking about UV degregration. 

Are the 49er masts clear coated or otherwise treated after they come out of the spindrel (or whatever it is they do)?

It's a bit of an issue with our boats (where the masts are usually clear coated and the view is you should put them away). But leaving the mast up saves a lot of rigging time on a frequently used boat.

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As part of the program we are doing now, WRT the switch from Southern to CST (and I hasten to add, Southern made a decision, we tried to get them to reverse it, but alas, they would not, which set us off on this path of a new mast), but as part of the program, we took some std CST mast (they happened to be C-Rigs) and have had them exposed now for 3 years in constant sunlight.    One is a flag pole, in my back yard, another we actually worked out the sort of load that would be on a and 49er/C-rig/WING tip and then mimicked that with a bit of shade cloth that covers my wife’s car, so every time we get a gust, this spar flexes not to differently from what a mast would.    We had one instance where a truck torn the whole thing out of the ground, but again, it has been in the weather 24hrs a day for now for over 3 years and we test it regularly. and it has not lost its "spring".

So whatever system CST (resin/fibre) is using, it appears un-affected by UV, both in terms of its surface "lustre" or it's mechanical properties.   It is NOT clear coated!

WRT the Southern masts, they insisted on clear coating them, and I do believe that clear coat is a UV inhibitor.  

So whether you can leave your mast standing will depend on who made it and what they made it of!

WRT both the Southern and the CST laminate being used on the 49er/FX, then the answer is yes, you can leave them standing for extended periods of time without too much concern about the surface of the material degrading.

  

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5 hours ago, JulianB said:

As part of the program we are doing now, WRT the switch from Southern to CST (and I hasten to add, Southern made a decision, we tried to get them to reverse it, but alas, they would not, which set us off on this path of a new mast), but as part of the program, we took some std CST mast (they happened to be C-Rigs) and have had them exposed now for 3 years in constant sunlight.    One is a flag pole, in my back yard, another we actually worked out the sort of load that would be on a and 49er/C-rig/WING tip and then mimicked that with a bit of shade cloth that covers my wife’s car, so every time we get a gust, this spar flexes not to differently from what a mast would.    We had one instance where a truck torn the whole thing out of the ground, but again, it has been in the weather 24hrs a day for now for over 3 years and we test it regularly. and it has not lost its "spring".

So whatever system CST (resin/fibre) is using, it appears un-affected by UV, both in terms of its surface "lustre" or it's mechanical properties.   It is NOT clear coated!

WRT the Southern masts, they insisted on clear coating them, and I do believe that clear coat is a UV inhibitor.  

So whether you can leave your mast standing will depend on who made it and what they made it of!

WRT both the Southern and the CST laminate being used on the 49er/FX, then the answer is yes, you can leave them standing for extended periods of time without too much concern about the surface of the material degrading.

  

Thanks Julian

Comprehensive and very useful answer

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The new 49er masts are the CST tow-pro. They seem to be using the same construction on 14s and 16s (although different dimensions).

Was that a design that CST already have available for those classes, and suggested it as a solution for the 49er, or was it developed for the 49er and then the technology transferred to the other classes?

The current all carbon has had it's documented issues with inconsistencies at the spreaders, so going to a metal part get around the layup problems in these more intricate areas. But, do you think there will be problems with corrosion?

The old rigs with alloy and fibreglass sections (like 29ers) can be difficult to pull apart and need separating regularly, especially if sailed in salt water. I had the unfortunate experience of a mast giving way recently on me (an old, but hardly used mast, which had corrosion between alloy and fibre). 
 

Or are the metal bits made out of some super alloy, or had some innovative treatment? 

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7 hours ago, Mozzy Sails said:

The new 49er masts are the CST tow-pro. They seem to be using the same construction on 14s and 16s (although different dimensions).

Was that a design that CST already have available for those classes, and suggested it as a solution for the 49er, or was it developed for the 49er and then the technology transferred to the other classes?

The current all carbon has had it's documented issues with inconsistencies at the spreaders, so going to a metal part get around the layup problems in these more intricate areas. But, do you think there will be problems with corrosion?

The old rigs with alloy and fibreglass sections (like 29ers) can be difficult to pull apart and need separating regularly, especially if sailed in salt water. I had the unfortunate experience of a mast giving way recently on me (an old, but hardly used mast, which had corrosion between alloy and fibre). 
 

Or are the metal bits made out of some super alloy, or had some innovative treatment? 

From my understanding, the metal in the 14 masts is just aluminum isolated from the carbon with fiberglass. Idk about the long term maintenence involved with that, or how the rigs will carry similar bend and weight properties to the other 49er rigs. Interesting to have such a different construction than the southern rigs.

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It's a all new design on all new mandrels using tow-preg, which your right, is a game changer.

To over-come, we have insulated the alloy with GRP or teflon washers or glued the fittings on with Plexus.

 

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13 hours ago, JulianB said:

It's a all new design on all new mandrels using tow-preg, which your right, is a game changer.

To over-come, we have insulated the alloy with GRP or teflon washers or glued the fittings on with Plexus.

 

Sorry to be on the ignorant end of this discussion, but I'm very interested in the outcomes; especially as I contemplate putting a new boat together and want to avoid some of the persistent issues I've had to date with carbon masts and associated fittings.

So can I ask (having not produced very much with a quick Google search)

What's tow-preg? [and if it is a new manufacturing technique for masts, about when did CST adopt it, and what makes it better]

What's Plexus? (which the context suggests might be some sort of glue one might use to glue a spreader base to a carbon/fiberglass mast)?

And if a fitting is not glued on, but fasteners are used, how does a fiberglass insulation stop issues still arising with fastenings that need to go through the insulation and underlying carbon to achieve their job (and here I've had very indifferent results from that gunk - momentarily forget the name - that is meant to be used as an insulation agent. Whether you use it wet or let it dry, as you put the fastening into the tightly fitting hole it always seems to wipe the gunk off)

Sorry to drag the discussion back to such basics, but I'm really keen to understand these issues better.

 

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14 hours ago, JulianB said:

It's a all new design on all new mandrels using tow-preg, which your right, is a game changer.

 

 

By the way Julian, are you still coming up this way?

If you're here on a Sunday, I can offer you a nice Fifteen and competent (but light light) crew for a club race :rolleyes:

The Olympic Nacra 17 crews were training out of our club few weeks ago and -since they came out of skiffs - we had the girls from the boats take skipper or crew places on a couple of our boats. They had a great time

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8 hours ago, Rambler said:

Sorry to be on the ignorant end of this discussion, but I'm very interested in the outcomes; especially as I contemplate putting a new boat together and want to avoid some of the persistent issues I've had to date with carbon masts and associated fittings.

So can I ask (having not produced very much with a quick Google search)

What's tow-preg? [and if it is a new manufacturing technique for masts, about when did CST adopt it, and what makes it better]

What's Plexus? (which the context suggests might be some sort of glue one might use to glue a spreader base to a carbon/fiberglass mast)?

And if a fitting is not glued on, but fasteners are used, how does a fiberglass insulation stop issues still arising with fastenings that need to go through the insulation and underlying carbon to achieve their job (and here I've had very indifferent results from that gunk - momentarily forget the name - that is meant to be used as an insulation agent. Whether you use it wet or let it dry, as you put the fastening into the tightly fitting hole it always seems to wipe the gunk off)

Sorry to drag the discussion back to such basics, but I'm really keen to understand these issues better.

 

Look at cst composites facebook. They provide details on plexus vs spabond for glueing masts and I think some on their pre-peg construction (towpro)

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Towpro is our modular approach to making masts which means you can change out sections to tune stiffness ( cheaper and quicker than changing luff round) , Other advantages in easy transport around the world and can change individual sections if a mast breaks. The metal fittings are machined/ anodized in house at Cst and also be changed to suit as well. Overall lower cost of ownership and more precision. 

16ft Skiff #1 Tow Pro Mast

16ft Skiff #1 Tow Pro Mast

The tow-pro design seems to be this inter-locking assembly. 

Their older designs seems to have more moulded carbon bits, including spreader mast brackets and forestay tangs. The tow-pro seems to integrate the spreader brackets in to the mast tube joins. At the same time they've gone for bonding on an alloy the forestay tang.  

I think carbon tubing is easy and relatively cheap to manufacture, but increasingly small and complex shapes like spreader brackets and stay terminals are much harder to ensure good consistency. There are some areas where metal is a better material. 

The difficulty with metal is you then have to integrate it to the carbon. A shed load of rivets through carbon isn't the best. So the ingenuity seems to be finding the correct glue for the stay terminals and using nylon and an locking join at the tube joins / spreaders. 

 

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Thanks guys

I've looked through the web site and like what I see. I've followed the CST site in the past and sometimes feel its a bit disappointing really explaining their products.

I hope we can get it to fit our class (limited numbers, but hopefully we can somehow use a slightly shortened version of another class's).

And for those following the discussion, Plexus is a new formulation of epoxy glue with superior properties binding ally to the carbon masts.

What I'll be looking to see is whether they expand their range of glue on tangs. At the moment they have only a moth forestay one.

In fact I'm a bit surprised they didn't incorporate tangs into the alloy spreader moldings.

I'm hoping this all moves forward quickly because I'm contemplating a new boat. 

One thing that puzzles is that the spreaders don't seem to have fore and aft adjustment like you would normally have on the lowers.

 

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There has been quite few ungluing of moth fittings (hounds and spreaders) on towpros, but I can explain most of them with very extreme temperatures (i.e. Perth) and most importantly wrong glue used (spabond vs plexus).

There is some kind of myth in the moth class that everything has to be glued with spabond, but for alluminium on carbon seems like plexus is the way to go.

And it also generally seems to manage heat better...

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Firstly, Plexus is Methacrylate, I think it's abbreviated as MMA.

Not sure it's related to Epoxy, I am not a chemical engineer, but it sure smells different!

Its primary use is gluing your cars together, and it used correctly is truly amazing stuff. 

But there are a multitude of Plexus’es and you have to use the right one for the right job.

We tend to use MA420.

It is slightly elastic (far more elastic than epoxy) and like any plastic it goes soft at high temperatures.

So a hot carbon mast with no venting in Australian sun, goes way beyond most plastc’s critical temperatures, and also beyond Plexus’s “yield point”.

Used well, it's a really great product, but with the 49er GN's we have upped the surface area about 25% and we are venting the masts.

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Rambler, I owe you a fuller answer.

Re visit, QLD/Covid has destroyed many plans to go sailing on Wraith of Oden, and therefore transit of you part of the world.    Plus presently, I am a shipwright again, taking space in Somersby, doing the project I expected to be built in Milan, then Melbourne (2 strike rule) so got a tad on.   Got a wedding in Brisbane early Nov, but I think I'm flying.

Re Tow-preg, it's pre-impregnated filament, so instead of the carbon filament being dry, and passing it through a bucket of resin this stuff comes with an exact amount of resin in it.   You keep it cool, very similar to "pre-preg" unies.     It was developed from the aeroplane industry and aero-space, so tolerances are a lot finer and therefore repeatability is that much greater.    But it also requires very different tooling, as in hard anodised alloy tools with no release medium, and a lot of the old tools are "polluted" and can't be re-used.

Re Plexus, I think its ITW https://itwperformancepolymers.com/products/plexus and it is a methacrylate, not a epoxy. 

Significant differences between the types for instance in one applicant MA425 dose not work where as MA420 dose work.   And the opposite is true.   Again we tend to use MA420 but you need to go look at what it is you want to do and go from there.

WRT gluing the castellation rings on, we have Teflon washers and use MA420 so there is no Alloy – Carbon contact.    AL-C is the worst, they eat each other.     SS-C is nowhere near as bad.   Monel or Ti to Carbon are almost benign. 

And Hard-anodising (of the alloy) also greatly reduces the chance of electrolysis.

Re key plates and the alike, that are through riveted.    1st think, for electrolysis to happen you need electrical conductivity and you also need a medium (acid) which in this case is salt-water.  Barium Chromate (otherwise known as Cocky-shit) dose a amazing job, but its possibly carcinogenic.   Tuff-gel is also amazing, but then again so is slightly coagulated varnish (it works via water-proofing).  The trick is to do it well and use one of the inhibitors.

 

 

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23 hours ago, JulianB said:

Rambler, I owe you a fuller answer.

 

 

Thanks for taking the time Julian

Hopefully one day you'll get through to Qld. Better still if you can make time for a sail and even meet our group (I'm sure they'd like to meet you).

We're presently celebrating one of our women trainees who earned herself a mainsheet position on the 18ft skiff that just won the Queensland States on the weekend. Go Clare!

We have some amazing women in the group

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I hope to transit a few times in November, and I would love to drop in, have a chat with you and whom ever.   

Did a "skiff chicks" thing a month or so ago, great to see the much better sex having a great time.

       jB 

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2 hours ago, Irrational 14 said:

Clean separation. Possibly not enough adhesive or bad prep or both.

Actually the split trailing edge seems to bear some responsibility.

Mind you, I'm having trouble from the picture seeing what overlaps what. I assume it's not just a butt joint, but can't see a tongue

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Re: "Taking the mast down"

We learned the hard way, that there is a reason to do it, if you want your mast to survive for way longer than just  3 years.

It its too much hassle the other option would be to paint it white, light blue etc. like it is done on yachts. Does not look as "sexy" but temperature will be lower and protection will be way better due to more pigments than with clear coat which is just a bad compromise with marketing.

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On 1/14/2022 at 8:40 PM, Rambler said:

Actually the split trailing edge seems to bear some responsibility.

Mind you, I'm having trouble from the picture seeing what overlaps what. I assume it's not just a butt joint, but can't see a tongue

Yeah, I think the trailing edge split. 

Looking at it how it sits now the internal aluminium arm can't be that long. So I would say that needs to be a tad longer. Maybe the carbon spreaders needs to up wall thickness where it sits over the alloy arm, or even just have a wrap or two of UD fibres around the outside. 

Looks like a foil shape to the spreader which creates quite a sharp trailing edge to cut it's way through the carbon. Maybe better with an oval section at the inboard end. 

It sounded like from the FB post that a kite caught the spreader on the hoist. So it will somewhat depend on how much you view that as part of usual use and how often that type of incident happens as to whether it's a design fault or not. Could be a 1:1000 event that wasn't picked up in the 500 test sails they did. 

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