ETNZ IACC120 Dual build thread

Other America's Cup Boats
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8 months after starting this project, I’m finally there and finished with rigging the today, what a sensational feeling …Claudio a huge THANK YOU, for my first scratch build I’m so thankful that you took on a novice to learn from your incredible talent, skills & wonderful expertise on this project, the final result way way beyond my expectations, this experience will stay with me … life long !

Unable to get on the water until next weekend (business travel has me on the run again) but once back I look forward to posting few photo’s of her maiden voyage.

Gillies nice to hear that the Northern ice has just about gone, wishing you a great sailing season !!!

Cheers Alan :zbeer:

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Hi Allan,what a nice boat and i am sure it will flow like an arrow.Indescribable the feeling of fulfilment with the help of a master.Cheers Gilles

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Allan,who made your sails?And the deco on them? Gilles

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Hi Gilles,

Sails made by Todd Olson from Isobar http://www.isobaryachts.com/index.htm he is based in Wellington, N.Z. and ships world-wide.

The sail deco was done by myself by tracing graphics using Edding permanent markers … thought hard about having printed self adhesive sail deco as you have, they definitely look the best however the final decision was a weighty one. The final complete boat sailing weight in the the water came in 4,533 grams (33 grams over minimum weight) and I always like to keep as much weight as low as possible in the hull, hence I opted for hand deco option.

It was the alloy mast that blew my weight budget.

Cheers Alan

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Hi Allan,
many thanks for your words, but your work is fantastic !
I fill like a teacher when discover a talent within his pupils !
Tank you ! Waiting the “Event”
Cheers
Claudio

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Claudio thanks, good pupils come from great masters (teachers)

I have one last question, I did a balance check early this morning and found the C.G is 180 mm from bottom of the hull using 74 Dm2 rig, full keel length including the bulb is 419 mm. Not knowing where the C.G should ideally be I kindly ask if this position is ok ?

Cheers Alan

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In my opinion is useless, particularly with a ‘close rules’ definitions.
Obviously if you put a 80dm² of sail the CG value will change a little, but again … no use .
Being the fin/bulb a fixed element and the minimum weight limited to 4500g, the CG will stay there where you found it, if you increase the hull weight the CG will move toward the hull.
At the end it will indicate as much close you are with the rules parameters, probably 180mm is the maximum you can get, but this information stand alone and not exploitable ! It probably it will tell you statistically how good you are in making several models under the same rules.
You should ask Matthias or Alessandro what are their values.
Let put in another way: 180mm tell you how close you are to the rules. A boat of 4650g will have less than 180mm
Cheers
Claudio

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HU HU! Alan compliments!!! Very good work! I can’t wait to sail togheter! I’m seeing the boat details and I found many good “racing” components and solution: you used well the Ravenna’s experience :wink:
Can the Fly Emirates New Zealand Team Germany tells to Ainghi Team Roma some datas of your hull or it is a secret? AHAHA!!! What is the keel flession in mm, with a bulb of 2800g and 380mm of arm? What is the Sail set 1 complete, weight?
In change I could tell you the balance point value of my boats…

p.s.
We wait images and comments on IACC forum!

A little movie of a training regatta between my two Alinghi…just to charge you!
http://www.youtube.com/watch?v=sCpktxcIMG4

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Well done Alan! Now, what about her sister Ship!

And again, thanks for all the postings which has allowed me to gather the information to feel confident about building my own! (deck about to be made, then just sails and painting).

Mike

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Thanks Matthias, apologies for the late response (just back from business trip) I’ve planned to be at attend all 3 regattas in Ravenna, will inform with separate PM.

No secrets on this build, have attached all weights etc. for you to view & comment on please. From my perspective can say the following:

Complete Hull – I feel comfortable with final weight at 872 grams, it is strong and a rigid platform.

Appendages – Definitely got all these numbers in the wrong places with complete keel fin and bulb minimum of 3,000 grams I would like to reallocate weight differently from what I have by taking more weight off the fin and transferring it to the bulb, here I’m working on building CNC fin and need to mould heavier bulb … that is in the pipe line now for the sister boat.

Rudder is well under budget weight, (-38 grams) but it “looks” too big optically, it has been made exactly to Claudio dimensions, I have made 3 others rudders with smaller surface areas and will test once I have the rig tuned with original rudder, it’s not a weight issue this a matter of decreasing drag.

RC Gear – Maybe only weight saving here will be Lipo’s and this is on shopping list for sister boat as well.

Total Rig – here I’m only 10 grams over budget weight and this is using an “Alloy mast”, Changing to CF mast together with lighter materials for the sails should have more significant weight savings and once again going on the 2nd sister boat.

With these further possible surplus weight savings it becomes a question of where to use the additional movable ballast to improve the balance the boat & I will only know that after the first hull hits the water this weekend and is finally tuned.

Hey love your cool video of team Alinghi and looking forward to getting together on the water with everyone at the Italian regattas …

Mike really glad to hear your nearing completion & look forward to seeing some photo’s when you are ready, to your question when will the sister boat be finished ? well actually I now have two other sister boats on the bench, reckon the 2nd will be finished a couple weeks after I have fine tuned this 1st boat, need to see what other changes from 1st boat need to be made before closing hull.

3rd boat is a full experimental platform for airfoil mast with soft sail and to play around with fixed wing sail and delta rig, plus goofing around with adjustable bulb angle and a rudder integrated into keel fin and few other ideas, like a bendy keel.

Cheers Alan

P.S Matthias now waiting on your balance point values :slight_smile:

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Nice review Alan! I read it with very attenction! And I can’t wait the time to sail with you…Alinghi vs ETNZ…wow!!!
Regard the balancing point of my Alinghi SUI-91, is 220mm from the lower part of the bulb.

Cheers Matthias

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Interesting and obvious after the publication of Alan the measured caracteristics.

Assuming that the total fin lenght is 420mm +/-1 in booth cases, we can see that the sum of measured distances from hull bottom and from bulb bottom is : 180 +220 = 400mm,
therefore the CG of Matthias appears to be closer to the bottom end by 20mm . Observing the data, one can see that the Alan boat rig assembly is probably heavier due to various factors as the alluminium mast, fittings and lenght, while the Matthias boat has 3000g at the fin/bulb and very probably a lighter rig.
All togheter, this result, is demostarting the overall mass distribution may be lowered by carefull choice of materials. In teory lowering the overall CG is beneficial to the righting moment.
It is told that all weights that can be gained shall displaced to the keel, in this case the keel is fixed to a maximum of 3000g and the over all displacement is 4500g.
Under these conditions, very little can be done, the only margin of gain remains with the rig and fittings at the condition that the minimum limit of 4500g is not already achieved .

At the end is visible that the fin/bulb assembly could be improved by reducing the fin weight and transfer 30/40g to the bulb, while on the other end some grams can be gained.
Little detail, the mast of Matthias is shorter and this can be the greater contributor to le CG shift !
Cheers
Claudio

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Hi guys…
This is quite an interesting direction for me and good info for others!
I have to stress that gaining as much righting moment by good material choices and better design is the key.
After a lot of thinking, I have managed to get my fin down to 110 grams. The rest of the 2890g is in the bulb.
I will check and see where my yacht’s CG is and get back to you…

Cheers,
Jim

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Claudio you right the difference is my rigging, once I can get my hands on TD Model CF mast and a few other little weight re-distribution (namely keel fin) …she will be in the running :slight_smile:

Jim …I’m a 100% with you buddy on keeping weight as LOW AS POSSIBLE.

Today was launch day and honestly I’m lost for words, this boat is like silk on the water and flys like a rocket, I’m so taken back on the performance … it is just simply PERFECT !!. My only dissappointment was that there was only a whisper of wind today and needed to loosen everything up but it was huge rush to catch little puffs and fly in the clouds with excitement … UNBELIVABLE !!!

Claudio … I made this video as tribute to you for valuable time you afforded me in this wonderful project … THANK YOU !

//youtu.be/6rC5lwBzEIM

Cheers Alan :zbeer:

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Hi Allan,nice to see your rocket in the water.Very happy for you,the feeling of sailing a scrachtbuilt sailboat like that is incredible!!! Cheers Gilles

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Alan compliments! Good sails set-up. The boat seems to move well balanced in water. Have you find a lake near you home?

Cheers Matthias

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Thanks Gillies, you so right ! … so now begins the fine tuning part and practice, practice and more practice to catch-up with you and other top Italian sailers Matthias :stuck_out_tongue:

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Tanks Alan for the nice presentation and the great work you have done.
After all deserved compliments is time to make some comments.
You have now a period of tuning and I pass a couples of remarks from my side :

1 - The boat is too flat in the water, in principle with almost no speed the nose should be higher. Even with almost no wind the boat tends to put the nose down because is also already down at the start, you need to recenter some weights or add some ballast in the rear to lower the stern about 1 cm in static conditions
2 - A counter weight is needed at the jib boom in order to easy the butterfly opening. In the film is noted that you tried to obtain this effect unsuccessfully just because the counter weight is missing.

3 - in this picture can be seen that the main leech is too loose
http://www.rcsailing.net/forum1/attachment.php?attachmentid=5684&d=1273353708

Good Tuning !

Claudio

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Eyes of an Eagle great stuff Claudio thank you …

Jib boom needs rethink, pivot point needs to move back at least 5 mm and the outhaul was not working too well (see loose sheet under Jib boom) and it does need a counter balance weight for easier butterfly in light airs.

Main Leech too open …ahhh hmm…:scared: I installed the Vang incorrectly with maxed out setting, needs a little surgery to get more adjustment.

I’ve added more pictures to view the LWL, I had not measured it as I just wanted to get on the water to see her sail. Given there was virtually no wind I thought the LWL looked quite good (very close to the plans) you now saying need to lower the stern 1cm has me a little puzzled (plan wrong?) but I know what you mean when the wind increases how the bow will dig in more.

Need to wait for more wind but in the mean time I will move the batteries toward the stern and measure LWL.

Then again looking at first pic it looks as you say “flat” but other pictures not, could this be optical illusion from my cheap camera :lol:

Cheers Alan

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Hi Alan,
the boat is statically horizontal no doubt.
The need to lover the stern is an artificial way to obtain again an horizontal LWL once sailing at moderate wind speed, let says 5kt.
The remarks are noted in the picture. The quote 277mm is simply the anchoring at 253mm for the main boom +10% = 278mm
Cheers
Claudio