new room for us ac20 guys

hey guys
just talked with a friend and we have a forum for the ac20s. we can dicuss what we need there. also who is realy interested
check it out

Great idea Cougar I?m in


great news welcome . all anybody has to remember is that thi sboat is just alittle bigger than a normal IOM. but has alot more sail area. and allows all material to be used. you wanna use carbon firbe. go right ahead. and anybody else who wants to try this. come on in, and and give it a try. so far nobody has an advantage. I have a ac20 , and chicco has a ac 20 boat. we have been playing for a while. the french and germans have them also. so nobody realy has an advantage. we are in the process of right rules. if you wanna say. all we ask for is an attempt to build one. you show us a picture. and you get a say. I never once said it had to be in the water. just show us you are trying. and beleive me . we will help as best as we can
just ask some of the guys
most rules will be held at the other forum. just so that we dont get anybody here mad. we want to keep things civil

hi guys
tried to post this on hardcore. but it did not work. so i will post it here first
i worked with peter Rechenberg on these and made some changes but this is just the first draft for the ac20s feel free to talk about them. and suggested changes.

OK - humor me - what is 1/20th. scale size and why do we need conversion calculators before we can decide whether to build a boat? Can’t you simply post a maximum/minimum size, sail area, etc. and make it easier to new sailors/builders to see what 1/20 equates to?

No need to make them have to go find real boat sizes/dimensions, then calculate 1/20th sizes for dimensions they might not already have (or are impossible to find), then convert from metric to feet/inches.

Just suggesting a way to make it easy to decide if they want to play - don’t make it a big mystery.

Only a suggestion of course. Like the Mini40 class - without sizes, most might assume (incorrectly) the boats a 40 inches long - or maybe 40 meters ?

Just curious - and I appreciate that the rules are just a draft - but why is the ballast ratio so low?

to be honest. the reason for the “ballast” being low. is because this is not a very big model. my boat uses a IOM keel. and it works fine. i can make the change to a heavier bulb when i go to the bigger sails. both work fine for me. but if anybody wants to make a suggestion. go right ahead. we are listening. my nzl 60 is 1.27 meters long so not that much bigger than a IOM

I don’t think that’s a problem of the ballast being “low” but more of the hull being heavy, a lot heavy, as you said it’s only (around) 20 cm longer than an IOM but more than 2 kg heavier, a ready to race IOM hull - minus rig - should weight around 1.2 kg, a proposed ac20 hull should at least weight 4 kg, that’s the minimum weight of a rigged IOM. Personally I don’t think that you can have weights restrictions in this type of class, different design will have different displacements and different bulb weight. The same with the number of channels allowed (“2 moveable surfaces (i.e. Rudder and trim tab on the keel)” allowed and “A Yacht shall be controlled by no more than 2 channels” how can I control the two movable surfaces and sails?) or any other restriction, like max draft, what if the 1/20 scaled down boat has a draft of 52 cm? The rules should be pretty simple, just something like:

  1. 1/20 scaled down version of the corresponding IACC boat
  2. Max. keel draft 360 mm.
    Oh, and obviously: 3) Constructions materials shall be of no higher density than lead (11,300 kg/m2)

BTW, genoas and spinnakers should be allowed too.


Moderaters jumping ship to new forums??? is this ship sinking??
BTW the AC20 rule as presented would never interest me.A bit to “airy fairy” for serious racing in my view.

I am going no where. this was just alittle pet project i have. and this would be a good place to have an open dicussion. you have this forum to have your footy. i would not mind having somewhere to talk about ac20s that is all
i am moderator here.

Footys started here with one guy and an idea.
Your class can to,its no different
At for 9 years


I have not taken the time to read the rules yet… just being able to read the forum can be a luxury sometimes… but I saw the post about the hull weight and use of materials. Let me nail one thing right off the bat. If you want to give the class a chance, do not predicate it on light-weight hi-tech materials (spelled EXPENSIVE)

You can have a WONDERFUL class of boats here, and one that up to this point I have fully intended to produce… but if the rules are structured to benefit building with carbon etc… forget it. I don’t need another carbon project. It’s too expensive period. You can put a min weight on the hull, and you eliminate carbon right there. If someone still wants to build a carbon hull and comply with the min weight… be my guest. If you can make the 1 oz difference between glass and carbon work for you, have at it. There is a major difference in price and construction. If I were king, I would make it a min weight hull… AND fiberglass or wood construction only. Lower the price, keep it affordable, the class will grow.

Also, I will not even consider building an AC-20 unless it has a genoa. period.

If I had my way, they would either be mandatory (GASP!) or I would give a HUGE (as in HUGE!) advantage in sail area for boats that use them. It’s just TIME for a genoa class boat.

As to the Scale… Geez… not like it hasn’t been done before… J Class is 1/16th scale, AC-15 is 1/15th scale, AC Class is 1/12th scale. All it means is that you should comply with maintaining a scale boat. It could easily be backed up with what the general consensus is for the dimensions of the actual boat. Again, citing the J Class… each boat is assigned by the Class Sec and was approved by the Class membership what the LOA, displacement, sail area, were to be for each boat (Ranger, Rainbow, Shamrock V, etc) and they are all surprisingly competitive. No one is going to show up at a regatta and complain that your boat is 3/4" too long. Again if you think about it… 1" = 20" on the real boat so if you are off an inch it is not a HUGE factor. Most builders can hit within an INCH.

These boats are going to be very close to M class in size, and speed (FAST) and would be a delight to sail. I hope that it does grow, and I think that once they get on the water they will do so.

Be brave - think 3 Meter !

Hey Don’t tempt me! I have those plans hanging on the wall in one of the shops right now… mighty tempting… I wanted to do that 2 years ago but common sense won out… (Homer: STUPID BRAIN!)

I would be curious to learn what the current record is for largest R/C model sailboat and sail area. That could be a fun won to go after. I don’t think converting a real boat should count… rather a dedicated, specifically built model.


The future of the airforce includes pilotless drones.

Maybe the Navy will be interested in what you are proposing. :wink: