IACC 120 Fleet grows by 1 more again.

I have been very busy the last 4 weeks at work, and not a day off either. None the less we have squeezed a bit of time to put the first boat in the mould. Hull 1 has gone to our sailmaker, Stephane. This is his first go at boatbuilding so he is “under my wing” at the moment. This is the first chance I have had to post.
I have put up some of the build photos so you can see how we do ours.
I have just ordered the carbon for my Ultra light edition, Hi modulus 96 gsm unidirectional…I am going to try something a bit tricky and lay up the hull with uni’s… but thats another story.



Hi Jim, really nice and tidy work there mate!, jut curious about a few things from your pics, is that a prepreg uni in the photo (image 663) or is it in a wet out state?., wish I could track down some 96 gsm down here, so far no luck. How many layers did you build hull with?l

Also noted in your bag , seems like you are not using breather just straight release film over laminate, if so how do you get the air to track out of the bag when sucking it down?.


It looks like the breather fabric is blue. Noting the nice U shaped bulkheads, have you had any problems of them “printing” through the hull? It took a year or so, but I can see the location all of my bulkheads through my hull now :frowning: I’ll be laying up another hull soon…after making the molds, and would love to avoid the print through on it.

Hi All,

This yacht I elected for a simpler layup and its a 300 gsm RC 300 but with a ‘superfine’ 3K tow in it… I am building the moulds and supplying the technical input whilst Stephane is the one doing the work. sailmakers have very good hand -eye coordination! For the last two Cups, Alinghi used sailmakers as laminators to layup pre-preg components because they are used to dealing with fabrics.
For mine, when I get to build it… I am using dry T700 50mm wide unis 96 gsm @ 0 (along the length of the hull, with minimal overlaps)
and 1 layer T300 RC 96 @ +/- 45 as purely a binder to stop the uni’s from splitting. That will be all thats needed as you gain so much stiffness from the shape of these yachts.
I use SP Ampreg 26 as well - This is SP’s best laminating resin.
The carbon is available in Germany and they ship worldwide… If you need the info then let me know.
The blue material is a special mesh we use as a breather . Its primary function is for debulking pre-pregs but in the high performance boatbuilding circles we use it for just about all laminating jobs as is nice and stretchy and prevents wrinkles in the laminate if you are going around tight corners etc.

Gotta go,
Last day of work today… Then my first day off in a month! Tomorrows gonna be a bit ‘dusty’!


I forgot the “print through”…

Yes, with any structure this thin print through is going to be a problem… Its caused by the tiny amount of shrinkage in epoxy…The best way to avoid is to post cure the boat. This "shrinks " the Epoxy fillets etc as much as they will go, then fair out the print-through and paint.


Thanks Jim, I appreciate the explanation; makes alot of sense using sailmakers for cutting up the laminate patterns, I could see in your pics that the pre wet out layup was very well done and I fully understand how hard it is to get a layup as clean as yours…Nice work from Stephane, does he use an adhesive to hold the dry laminate together?.

Probably I do not use enough carbon to warrant much interest from a European supplier but it would be great to have a company contact for it so I could give it a go, tried again today in NZ to locate some…think I might be onto a supplier locally but cannot confirm until Monday.

I use a fine diamond plastic mesh as a breather when infusing, had not thought to use it for straight bagging applications but I will give it a go…breather blanket is great but my main complaint is you loose sight of the laminate so you can never be sure the laminate is 100% clean with no wrinkles and pockets.

Cheers …Gary

Hi Gary,

We also have the same Diamond mesh breather I think… Its a white-ish colour. If its the same thing then its not quite as good as the debulk mesh as it tends to leave a heavy patterning on the final laminate. The blue mesh has two faces and laying it down the right way is important - one side is a loose weave that allows the vac to ‘travel’ easily - this side goes up! The other side is a much tighter & smoother weave that leaves a much finer and less pronounced pattern on the laminate when cured.
SP supply it - It comes in blue or a green/yellowish knit. Talk to any of the race-yacht boat yards you have nearby and see if they will give you some off-cuts to try out. If you can, cut it with a hot knife as this seals the edge and stops annoying little bits dropping everywhere and ending up in the final laminate!
The supplier for the carbon is here -
The site is in English, which is handy. Look under ‘fibre reinforcements’. There you will find all the offerings they have. ‘spread tow’ is where you find the T700. My 10m roll of carbon uni’s was just under €20, which I thought wasn’t too bad.
Okay - Here is another top ‘insiders’ tip…
When you are laminating, particularly light fabrics or fibre on the +/- 45 bias, first wet out the fibre on transparent plastic stretched out and taped on a flat surface. Vacuum foil is the best, however its expensive - but use a similar weight plasic to that. Then cut out the laminate and use the plastic as a carrier to hold the fibre and stop it distorting and loosing its shape. You can then place the fibre into the mould or wherever (plastic side up) like a ‘wet-preg’ and when you are happy, peel off the plastic carefully. This system allows you to neatly laminate in wet layup. If you have intricate shapes, then template in plastic first, then use it as a guide to cut the laminate out to the correct shape before you have gone anywhere near the mould etc. We do this for just about every laminating job I can think of, big or small, as the final result is seriously worth the extra effort.
Sloppy laminating is a pet hate for me!

I hope that helps!


Awesome Jim,

cheers for the heads up thats a great site with a great range of fabrics.

The mesh I have been buying is from adhesive technologies and is green and a little stiff…I had been concerned about the mesh imprinting and printing thru the exterior when infusing but actually it worked very well without any “printing” and this has been at full vacuum with very light layups…still I will try and track down the debulk you suggest. One good thing about the breather polyester fabric I have been using is that it soaks up excess resin very well…however the better I get the less excess to bleed thru…just need more practise with ratio’s I guess…
Thanks for the wet out layup tip…kinda reminds me of the bad old days when we used to layup some powerboat mould components by wetting out the dry laminate on large peices of cardboard and then picking the wet lam up and placing into mould…very messy work…especially with polyester…

When you talk about “vacuum foil” as wet lay up template you are referring to vacuum film plastic??.


Hi Gary,

You are correct - Vacuum foil is as you guessed… The special plastic that is used for making bags.
It has some great properties that make it exceptionally nice to laminate with as well, just expensive if you are doing a big laminating job!



Hi Jim, I hear you on the cost of vacuum foil…maybe not so bad for you but I buy it by the metre and man do they sting you for it, been trying to find a cheaper alternative actually for a while now as it seems to me its only polyethelene with a bit of stretch built into it…bearing in mind I do not need the very high temp stuff it is rated to as I usually bag no higher than 50 celcius.

Anyways, I can see some merit in the technique so will have a run with it at next suitable project. I am interested in your proposed layup schedule, I have been doing some experimentation with unidirectional carbon recently and the laminate stiffness is great, you said you were planning on a 96 oz uni carbon with a T300 binder on top…I cannot find the T300 anywhere on the site you linked me up with, is it a plain woven cloth or biaxial 96 oz carbon??.

Looks like I am gonna have to import a shipment of carbon in from US or Europe, just cannot find the light stuff here.No one seems to keep anything under 6 oz.

thanks for your advice…cheers


Hi Gary,
It is fine to use regular plastic for vacuum bagging, however I recommend a gauge is used to check and monitor the vacuum. The main advantage to the foil isn’t porous and most other thin plastic alternatives seem porous by some amount in my experience.
The T300 is the ‘standard’ plain woven cloths they have. I bought 0.5 m already cut on the bias 45. It was just enough and I should really bought more in hindsight.

Here is a couple of photos… The one with gauge shows the vacuum in millibars!

Cheers, Jim

Thanks Jim,it all makes sense now…actually I have recently got my hands on some vacuum foil which is quite thin (by comparison to most off the shelf foils) and has
very high elongation characteristics, it is working out very well as the heavier stuff I been using up to recently is better suited for large scale projects and just does not conform to some of the complicated smaller shapes I deal with.

Interestingly on the SP26 resin subject , I have been trying to get this as well and as I am sure you know…Sp have recently bought out High Modulus; As they are now known “SP-High modulus” have been dumping there old stock on the market here and are presently inporting a new range to distribute here…unfortunately they have decided that there is not enough demand for SP26 Ampreg and so are going to carry SP22 and SP106 only. I have had a read through the datasheets for the SP22 and I have to say they are about the most comprehensive resin datasheets I have ever laid eyes on, so my question to you is do you rate the SP22 as a worthy alternative to SP26?.

Looking at your pics, I am thinking this is the newest hull you are now onto using the 50mm 96oz uni??, part way into layup and wet out!.

On the gauge issue, funny to see you are using CPS vacuum equipment, by coincidence our company down here is CPS LTD (custom pressure systems) and our business is pressure management. I am familiar with the gauge you are using and I am very fortunate to be able to use our own calibration laboratory gauges for my vacuum jobs at home, these are super accurate and as I am fairly anal about record keeping of all data when laminating (weights/temps/times etc…), the gauges I use have the feature of digitally datalogging the vacuum process for future refence. Probably a little over the top but I have found over the years I need to keep good records to improve quality and its also a good way to monitor resin performance.



Hi Gary, I like the gauge! I wish I could get my hands on one of those… The CPS gauge was one I picked up on ebay… It was the price more than performance that swayed the purchase.
The pics - Yes indeed, you have it right… The unis are pre - wet and then applied into the mould on plastic as I described before.
The other was the Vac on the hull bag after laminating. I fully enveloped the entire mould to get the best vac possible. We process pre-preg at those numbers! You do have to be a little careful how much vacuum and when you apply it for the best results. I try and wait at least 2 hours after mixing before applying vacuum. This allows the resin to begin the curing process and helps prevent too much resin being drawn out and the laminate being too dry. But I don’t over wet the cloth so this is quite critical.
The SP 106 is not really what I’d call a laminating resin, its just too thick.
As for the Ampreg 22… Well having used it on projects before, I have to say that I am not impressed by it at all. It is quite viscous and not “nice” to work with… It is a basic laminating resin and that’s about it, fine for wind turbine blades and big, over engineered superyachts.
Do you have a West Systems supplier? If you do, then the Pro - Set system is the way to go. It is most probably a better choice than Ampreg 26! I have used this resin exclusively on Int. 14 builds, SWE 96, Ericssons 3+4. It was the only resin that was permitted and I would recommend it without hesitation. What ever anybody else might say, it is Ultra-critical to post - cure this resin system… 50c for 16 hours…
Sicomen also have a decent laminating resin, but I cant remember which one, sorry.

What resin do you use at the moment?



Well Jim, you could If you talk to the right person :),

Although what you are using is certainly good enough,so long as you didn’t want a datalogging feature which to be honest is a nice tool to have but really not important for a good bagging result.

The VG200 you have has some redeeming features…temperature compensated and resolution in mbar to two decimal places are the ones that spring to mind, on the downside…battery life is short, only three units of measurement available (I really like using kpa but thats a personal preference), and accuracy is quite poor which at the upper end of scale is not so good @ +/- 10% of reading. This is not really a problem when you are running at full vacuum but for me I often run for a while at -600 mbar during initial cure at this range your gauge would be good to +/- 40 mbar (4 kpa) whereas my gauge is good to +/- 2.5 mbar…well it really doesm’t make much odds but I do enjoy precision in engineering.

The main thing here is you are not using analogue gauges, it surprises me how many out there use mechanical gauges and think because the gauge needle points at -100kpa then thats what the vacuum must be :lol:.

The resin I presently use is Adhesive technologies ADR270 with ADH28 hardener for bagging jobs…my 20lt pail is close to empty so am looking at options for replacement right now…having said that the ADR270 /ADH28 combo has been very very reliable…45 min pot life and 90 min open time means I can comfortably get thru wet out without stress and as I usually have any job wetout within 30 min i can elevate temps a little as required to speed up process. It also provides a reasonable HDT if post cured at 50C for 12 hours.

The guys at Adhesive technologies in West Auckland have always been very helpful with technical advice and their service is spot on…they are also agents for West sytems so I will have a chat with them about the pro-set range.

Once again cheers for the heads up on resins.


Been working slowly on an all new female tool for the deck, to keep the weight down further…
It can be used with either pre-preg or hand layup…

Here is the next generation IACC 120,

I was keen to put the new hull onto the scales, she has everything except the mast structure in this photo, so the combined hull, internals and deck are 365g so far.
I think that should hit the target for a 4000g yacht.

It is very stiff and strong, 100% success!

AWESOME … great work Jim, looking forward final result …

Thanks for moving this to the Americas cup section… Sweet!

It looks like the project is on hold for a couple of weeks as we are hosting the Formula 1 here in Valencia and my schedule is manic to say the least…

Its been a while, however this project isn’t dead at all!
I am moving the new Iacc120 into new territories of stiffness and durabilty
I Have just installed the Mast structure, Final keel
structure and the Mainsheet post.
This is the ultimate upwind weapon…


Just thought I’d drop off some pictures showing the keel fin setup process… a dead flat & level vacuum table, 3 lasers, 2 plumb bobs and a mini digital level ensure that everything is true.