Hi everybody,
many are asking me what happen since a couple of months. Very kind of them. I’m still OK , but a lot busy !
It is true that the J Class Enterprise is in stand by, the reason is simple.
Some guys asked me to draw a new AC shorter then AC120. The main reason evoked, was that they need a more easy transportable boat. Personally I do not knows if this is the real reason. The boat of 1 meter lenght could be the ‘ideal’ …they says .
Why ?
I suspect that many are arguiing the eccessive costs of similar models lenghts, etc…

So the AC100 is born !

Actually, 2 models are drawn and 1st prototype almost completed. The AC caracter is keept but this time with an Open Rules just fixing the extremes values.

A new italian Club /Site/Forum is supposed to open soon. The aim being the promotion of the new Class AC100.

here the drawing used for the prototype.

Hi let you knows eventually with a ‘bild log’ as soon the italian site is officially open.
I promise, after that, I will go back to the Enterprise !

Great stuff Claudio :slight_smile: Every time I go down to my local lake with my AC 120’s I seem to spend half my time letting other people sail them :lol: people are most definately interested but the AC 120 is just little too big to carry around, as you say.

In an effort to try and encourage some local sailing & competition, I’ve started AC 100 with idea of building 10 complete boats and pass them on at cost …then I can have my 120’s all to myself again :stuck_out_tongue:

Never know … if it catches on we can have a group head down to Italy sailing regularly and enjoy some of their great wine & food.

Cheers Alan:zbeer:

Hi Alan,
great idea !
if you need some suggestions, this will be probably the official hull decoration of the AC100 Class. Hull color may change of course.
The “silver bullet” once again !

By the way the picture you sent refers to wich project ?

Hi Claudio, thanks, I’m a long way off thinking about hull decorations and will keep an eye out for when the Italian internet site comes up and see what they are doing for deco ideas too … I kinda like current AC deco schemes because people can relate to bigger boats when they see them.

I’m using your very first design with low draft 39 mm and Beam 148 mm. Will try the two different length keel fins 400 & 420 mm, but will wait for class rules to be established and take it from there.

Cheers Alan

Hi Alan
I see, you got it from AMON .
The Rules ? that’s it in Italian, but easy to read the numbers, what is not specified is ‘free’

Thanks Claudio, first glance looks very good, I will translate these class rules into English (German also) together with the construction notes you had posted on AMON also … then I will PM the translations to you for proof reading, if you don’t mind? then we could post them in this forum for those people who wish to build AC100.

Just a question, do you think there would be any objection to using the black AC logo instead of the coloured circle with 3 sails ? just can imagine people relate AC logo better and it is easy to apply to the main sail.

Cheers Alan

No obiections at all Alan, is supposed to recall the AC from 86 onward, but it is also an “Open Rules”…

A few other Hull deco ideas ?

Hi Alan,
very very nice.
At the time the AC100 Site will be open, I suggest you to insert them .

hi everyone.

how this plans fit to IOM ?
is there are some diffrents ? i mean the hull… etc…

thanks for answer.


The hull could be used in IOM, but may have performance issues by not using the whole length as sailing length. (IOM have plumb bow for max sailing length).

The hull would have to meet the max depth (60mm) and front bumper (10mm) - probable will be ok here.

The fin and bulb would have to meet the min/max weight (2300 to 2500 gms) and max draft. As drawn, the draft is too deep for IOM.

The sail plan would not be allowed and you would have to use the IOM sail plan dimensions.

The total weight of fully rigged boat must be at least 4000gms.

So the answer is probably ‘not very well’. If you want an IOM there are a number of free plans available that would likely be more competitive.


vary thanks.

but for free plans… yeea…
not even close …
in this boat i have every frame beutifull draw in pdf 1:1 and all of dimensions.

in free IOM boat plans i have frames “all in one” so… maybe it would be enoug but not for me… i am nooby and this is to difficult for me. .
and i asked everyone and everywhere… nothing…

this boat is fine because i have some stuff to 1m hull but will be nice if i could have some “class” boat…

but thanks for answer.


A friend is working to replace the mast, sails, bulb and fin to adapt an Americas Cup (the Chinese one) to a IOM rules. We would see what happens.

I have the idea that could be a success, probably not as fast as a Pikanto, but a cheap solution to have a competitive IOM for those like me with short budget and no manual skills to build one.

The Americas Cup boat was designed for race upwind-downwind and the crew is not allowed to hinking, like R/C boats, maybe the experiment have success. Who knows?

aXon, There are some free IOM plans out there that are pretty complete, including all shadows in PDF files (deck too), If that is what you are looking for, I can email you the plans for the Vanquish, or you can download full sized plans for the NouxII from Anders Wallin’s website,

I think the Laerke and a few others are available on Anders site too.

Don’t be afraid to purchase plans either. The price is not really that much when you consider what you will spend on the boat to build and rig it! $15 for plans to build a boat that you will have over $500 and LOTs of hours of time invested, is not unreasonable. There are some IOM plans from Graham Bantock and Brad Gibson that look very nice. And others too, I’m sure!

When I build from a set of plans with all of the frames layered on top of each other, I make 10 copies of that drawing, mount them to boards (such as foam board), then mark and cut out each frame starting at the bow and working back form there. There are a few IOM build threads showing the process, with photos, if you are interested in learning

Back to the AC100 !!

Starting from the bottom !

The Bulb is selected with the Bulb Calculator

My technique employ the lead foil 1 mm thick and can be used for any type of bulb size.
Is a single shot fast method
I need 2 days to produce one

For my model I need a bulb of 1750g

The images are self explanatory
More images to come.


The bulb will be covered with epoxy glass and paint for 2 reasons : a) to protect the lead from shocks and b) for ecologic purpose.
the others pics & end of story !:

Great job Claudio, my best compliments!

Thanks a lot Renato, the story will go on !

an other step toward the top ! The Fin and the Rudder

The fin is supposed to have a thickness of 7 % while the retaining brass rods are of 4mm. The finished thickness should be 4.9mm. Not easy but a will try.
The entrance will be composed of a carbon rod of 3mm while the exit will be using an Alluminium strip 100mm wide and 0.5mm thick.
Tha base of the fin is 2 balsa sheets of 2mm thick.
I starded with carbon cloth of 162g/m² , 1 layer at 45° and 1 layer at 90°.
The flexural test, as expeted, was non providing good results , therefore I adds another layer at 90° and again the flexural test was not satiffactory.
I decided to adds 3 layers of unidirectional carbon cloth of 85g/m² - this time the deflection is very small, see picture and the final weight including silver paint is just 140g as sheduled.
The pictures are posted on several posts

others pictures related to Fin & Rudder