2013 Italian IACC 120 Cup

The date has now been set (Sept 14-5th) where the Italian Southern fleet meets with the Northern fleet to determine the Italian IACC 120 Cup for 2013, this year I’m really excited to announce that we have growing group of skippers from Central Europe attending this year from Denmark, Germany & New Zealand naturally.

This two day event will be fleet racing to determine top eight boats for final match racing series that determines the IACC 120 champion for 2013.

Open invitation to anyone wishing to join us and if you are need of a boat for the event I’m sure something can be arranged on request, accommodation is near the course at approx €40 per night, so if your interested in joining us drop me a PM for further details.

This year I have built another new boat (I think this will be my last…:rolleyes:) and after painting should hit the water in couple weeks to start tuning in the lead up to the Italian Cup in September.

From time to time I’ll give you a update on my treats for this built into this new design of NZL-32 BLACKMAGIC as I verify them with two boat training where I have two different DSPL, adjustable keel fin length & different Main/Jib sail area ratios to test in the lead-up to the event.

A few training sessions have also been pencilled in with growing number skippers in Central Europe and like encourage them to add their contributions on their preparations also.

Mid of April (next month) I will also be attending the Southern IACC 102 fleet championship in Rome and I will give you reports of that event, here I will be using ETNZ-92 as my race boat there as my bench mark boat as she being used as training partner with NZL-32 BM when I return. To improve my sailing skills also will be doing as many of the German IOM events as I can this year….

The current Roman champion Matt with SUI-100 has spent last 6 month tuning his new rig and had unfortunate mishap last week with his new rig, boat was sitting on cradle in high winds and big gust hit and keel was resting against his leg and the force was that great that it snapped the mast … a new profiled mast with extra reinforcement is under construction now…. Will at least he did not do a jamming Jimmy and pitchpole :stuck_out_tongue:

Cheers Alan

P.S Sorry folks, there was a mistake with date, it is not 24-25th Sept correct date is 14-15th Sept …apologies (corrected above)

looks like it going to be a fun event… take lots of pics so those us can live vicariously through you guys.

bummer about the broken rig… I have learned that hard way as well that a boat in the cradle or being caried is risky when the winds are high… Lost an ec12 rig when i was carrying the boat and a huge puff… caught me off guard…

Finally Painting & graphics of NZL-32 BLACKMAGIC is finished …water still little hard in these parts so will another couple weeks before she hits the water.

Cheers Alan

Simply AMAZING !!! Alan
BTW how did you managed for the water decals ?
Congratulations !

Thanks Claudio, one of my better builds, as you see it (without electrics & fittings) came in at 783 gms.

For decals used thinnest sign writer adhesive I could find and printed CDR using commercial U.V inkjet with anti-U.V coating to prevent colour fade, then cut the decals using a plotter with finest blade off the CDR’s that managed to cut 2 mm high word “TEAM” on the bow absolutely perfectly & then double back adhesive over the top of the decal, peeled off the back applied to the hull …long exercise but great results …fingers crossed she sails as good as see looks

Cheers Alan

So is not a water decal !
What is the thickness ?
Generally what is looking nice is also good !!! hem!

It is called ORACAL 751 High Performance Cast Film, looked up the [u]specs online[/u] and technical data says 2 mill …which not correct, I’m guessing it is more like 0.20 mill ? but not 100% sure

I promised at beginning of this threat to give update on my lead up to Italian AC 120 Cup in Sept this year, I take the walk of shame for not doing it ! … being recently retired I’ve had lot on my plate.

Currently I’m working through fine tuning three boats to decide which to take to this year’s Italian Championship, firstly there is trusty old Jaguar GBR 75, then ETNZ 92 Ver 3.0 used in last year’s Italian Championship and newly finished Blackmagic NZL-32 Ver 2.0

Currently I get on average 3 full days sailing during the with week with lake all to myself, only down side is that I’m sailing by myself, scheduling one day for each boat and work through series of minor tests with changes made from previous session and then move into fine tuning for the days conditions and recording endless measurements of settings until have complete set of references for each boat and then practising buoy rounding and sailing different angles to wind to get feel for best VMG.

Each week you can follow me working each boat and if you see anything that you see that could be improved, please pitch in and give me your opinion on how to improve.

This week I will back-up a little to the Roman Cup final held earlier this year (April 14th) drove down to Rome on the Friday to catch Matthias (SUI-100) for pre-race practice on the Saturday, I decided to take ETNZ-92 with 78 dm2 sail suit (pin head main) after feeling not very confident in getting with the 79 dm2 square head main set-up right.

Matt had only just replaced his snapped mast for new one so we both needed a good tuning session to dial-in our boats, started out in light air in the morning and wind speed built up slowly to around 12 knots in the afternoon which was perfect conditions. As expected Matt who sails regularly with the Sth Italian group (10 boat fleet) was whipping my butt to start with & then we started a series of fine tuning sessions where only one of us made changes while other boat remained unchanged then sailed a few runs until was happy & then other boat would start fine tuning to catch the other boat.

In seaside conditions with choppy water with onshore wind ETNZ was taking on more water than I liked (my home lake rarely has waves) with roughly cup of water every 30 mins & I hate idea of having salt water inside the hull but by the end of the afternoon both boats were even in speed which surprised us both and felt confident in having a good set-up for Sunday racing. Took notes of measurements boat settings and headed back to my hotel to rinse-out the salt water and try and find where water ingress was coming from.

Sunday morning, had not found the leak and low behold my rudder servo was playing up OMG panic! :shock: Pulled the servo apart and sprayed it with WD-40 and got it running again (I forgotten to take spare with me) and then wanted to start set-up with previous day’s settings and you would not believe it but I had left my sheet of paper with settings in my hotel room ! by this time I was becoming frustrated with myself for being so stupid.

Unfortunately there were lot of no-shows with only four challenges plus Matt’s SUI-100 (defender) so fleet racing and robin match series was short to find challenger match-racing final that ended up between my ETNZ and Lorenzo ITA-95, By this time in the day my rudder servo was on the blink again and I had not done a good job in finding my settings from the previous day’s test session and ITA-95 beat me fair & square.

The Roman AC 120 final between SUI-100 & ITA-95 was convincely won by Matt’s Alinghi …sheesh and I had his measure on the day before, on the long 12 hr drive home I was thinking through how I needed to test to have a bullet proof boat for Sept Italian AC 120 Championships …which has began in earnest, stay tuned for next weeks update !

Cheers Alan

Sounds like you’re putting yourself (& boats) through a very effective training schedule - I’ll look forward to reading about how you brought the silverware home come september!!

Just out of interest, how does the bare weight of NZL-32 BM compare to Jaguar & ETNZ?

Looking forward to reading/hearing how the training/testing is going.




I will (yet again) speak out my intentions of participating in this event. A million things can still go wrong, but I intend to be there.


Really looking forward to having you join us Anders :wink: hopefully we can get some sailing time together before Sept so far have the guys from Munich joining and maybe another from Dusseldorf …the Central European invasion !

Row, the bare weights of the boats including appendages, class racing weight min is 4500 grams:

Jaguar = 4,380 grams
ETNZ = 4,050 grams
Blackmagic = 4,290 grams with two displacement modes 1) 966 mm LWL @ 4500 grams 2) 985 mm @ 4770 grams.

Played around with water tank I built to get static boat balance and could never get it right on the water, wasted a lot of time as boat balance affects helm balance as you know & did not want to start on sail settings until I got this parameter right.

Then found way of balancing the boats on the bench using C.B as reference point, amazing how accurate it is under sail … I will explain later.

Cheers Alan

The selection of the three AC 120s I’m trailing is primarily based on P.C: The Prismatic Coefficient is the ‘relationship’ (ratio) between the hull shape and the actual volume taken up by the hull. In short, it is a measure of the fullness of the ends of the underwater body or in other words the hull canoe body section forward and aft to the ends under the waterline.

For yachts the P.C is usually between 0.420 and 0.620. A prismatic of 0.430 is very low, meaning that the hull volume is less than half the volume given by multiplying the midsection of that hull by its LWL. P.C of 1.000 would describe a barge with square even mid section & ends.

According to hydrodynamic theories, a high P.C is better in constant high wind conditions with a smaller midsection means you are punching a smaller hole through the water but at the expense of more wetted area as we have fatter ends that creates is a bow wave, with a ‘hole’ (trough) in the middle of the boat and the hull is supported on the two wave crests at the ends this creates drag and as speed increases the wave gets longer & wetted area drag goes up roughly proportionally with speed, the trade-off is High P.C offers buoyancy and stability in heavier conditions.

A hull with the low P.C has finer (sharper) waterlines forward, a narrower transom and less wetted area than the one with the high P.C. In light air, the bow wave is minimal and the lower overall drag from the hull is due to reduced wetted surface area. Therefore to cover all conditions “theoretically” one should have two boats with different P.C (high & Low) to ideally match all sailing conditions.

The three boats I’m using cover the range of P.C plus using a little ClaudioD magic with his Blackmagic NZL-32 one boat design that has two P.C’s (plus few construction tricks of my own) I wish to see how BM fairs against Jaguar & ETNZ with dedicated P.C

Blackmagic – LWL (1) = 966 mm, Beam = 205 mm, Rocker = 50 mm with P.C of 0.558 (light air)
Blackmagic – LWL (2) = 985 mm, Beam = 205 mm, Rocker = 52 mm with P.C of 0.570 (med air)
ETNZ – LWL = 1010 mm, Beam = 180 mm, Rocker = 47 mm with P.C of 0.583 (med to heavy air)
Jaguar – LWL = 952 mm, Beam =192 mm, Rocker = 56 mm with P.C of 0.614 (heavy air)

If you’re only going to “build only one AC 120” valuable design point to consider is that a high P.C hull is more forgivable in low wind conditions than a low P.C hull is in high wind conditions.

There are many other design variables of course that affect boats performance such as shape, hull surface finish & appendages, weight distribution, sail size & ratios etc. but today I just wanted to give you an idea of my basic thinking and will move on from here.

Back to more important things, an update on AC 120 activities, The northern Italian AC 120 fleet has now increased with three more new boats with another Alinghi SUI-100 and new Mascalone Latino both with new skippers and Carlo has build ver 2.0 of Red Bull SWE 76 as improved progression from his last years boat.

It looks like Lukasz Koch from Poland (building ETNZ-92) now has a sailing companion in Grzegorz with his new SUI-100 that looks very detailed…hoping he & Lukasz will joining us in Ravenna, the numbers of Central Europeans is now growing quickly :cool:

Alan K1w120 (Germany) - In
Grigoris (Germany) – In
Jorg (Germany) - In
Landlord (Germany) - In
Lukasz (Poland) – In
Grzegorz (Poland) - ?
Anders (Denmark) – In
MartinL (Netherlands) ?

Hi Alan,
I’m very pleased to hear about the Polish progress!
Very good to recall some basics knowledge of sailing design concepts.
You probably mis the most important one that is the CF that define the hull design balance attitude !

Hi Claudio,

Yes LCF, the longitudinal centre of flotation being the geometric centre of the water plane is important boat design balance element where hull pivots on the water where LCF should as close to LCB as possible from level LWL to max 30 degree heeling. If it does move I understand it should only be only forward (not behind) and less than 1% of LWL movement when heeling, however, once the hull is designed & built to plan it is fixed and then coupled to the LCB, therefore in tuning the boat to sail on its LWL, I then only focus on LCB.

Here we can see the LWL shape of the waterline from above showing LCB & LCF. (illustrations by ClaudioD) Here I have to say this is one of the most important points between having correctly designed hull compared to something that is just optically nice looking …ah la cheap Chinese RTS yachts that makes huge difference in the yachts sailing characteristics.

LCB being the longitudinal Centre of Buoyancy of the hull is the point that the upward force of the displaced water acts. I have been following the rule of lining up the hull LCB with the bulb C.G @ 30% of chord from the front edge of keel fin. In my next post I will explain how I statically balance the hull to sail on its LWL where I’ve found fine tuning hull balance that 1 or 2 mm can make a difference to helm balance.

Cheers Alan

Even though theoretically does not sound quite correct, from my observations most RC yachts seem to sail best slightly bow high! If you can get your bow light it helps to sail faster in choppy conditions and will help to stop some nose diving in higher wind conditions. Wind pressure on sails pushes the nose down even in light to moderate conditions down wind. Bow down seems only helpful in very light drifting conditions, if ever!

Before I start with sail tuning on the water, one of the things I like to do is ensure the boat has good weight distribution (boat balance) or in other words, Does the boat sail on its lines ? managed to get the weight distribution correct within the hull?

To have good boat balance to me, starts with mounting the bulb to the keel using LCB line at 30% from front edge of the keel fin chord as reference with vertical line falling from the LCB to the Bulbs C.G. Depending how much free ballast I have to play with determines the distance between the bulbs C.G & hulls LCB, more ballast to play with the further the C.G is behind the the LCB, if boat is at minimum weight (or over) C.G needs to be aligned to LCB.

Generally I suspend the bulb level using plastic tie-downs that hang from a little bridge that hangs off the Bulb bolt, I built flotation tank in the backyard to check and quite honestly I found it complete waste of time, I would mark LWL on the hull and then slide the bulb backward & forward and move ballast in the hull until I found what I thought was sitting on its lines …the hard part is measuring LWL and bulb position while boat is in the tank & found it was royal pain in the butt !! …and sometimes never looked right on the water.

To have good boat balance LCB position is of paramount importance because all the static adjustments are based on the LCB to obtain a longitudinal equilibrium as it is the core relationship to the boats stability. The fastest & easiest way I have found is to do this using a level split saw-horse using a round wooden dowel on the bench and balancing the hull on LCB point, it is more reliable & accurate than using the static flotation technique.

Why bother of doing this ? well I’ve found when the movable ballast weight is too far aft when closed hauled this will contribute to the boat wanting to bear off (lee helm) and with weight too far forward contributes to boat wanting to head-up (weather helm) you can counteract this by adjusting boom angles, but then you find the forces of CLR/C.E are fighting against the hull and the boat never seems to want sail nicely in its groove on the water.

Personally I like to sail with neutral helm and look for smoothest water surface just behind the boat under sail, if there is any turbulence in the boats wake, normally means to me that something is not correctly balanced and boat is fighting with itself, causing unnecessary drag. One of these pictures shows turbulent wake behind the boat, can you see which boat ? and what is causing it ? (btw all boats have good hull balance)

Just a quick overview of Keel fins, have been tinkering around with various weights and lengths, you will see Jaguar is not as stiff as ETNZ & trying both worlds with Blackmagics Keel.

BM has a drop Keel design that can be adjusted (30 mm) from 390-420 mm draft using spacers on the head of the keel fin, wanting to see how much difference there will be with drag reduction (less wetted area) particularly in light air.

Further with BM I shaved the bulb down by 200 grams (more reduced wetted area) and use a hollowed out keel fin where I have the option to load the fin void with the lead bulb shavings to adjust weight from 2800 – 3000 grams.

Will be off the air for next 2 weeks sailing a F-18 island hopping in the Med … when get back I’ll go over sail settings and tuning on the water & try to decide which boat to use at this years Italian AC 120 championship.

Cheers Alan

the jib is really tight, the main has lots of camber, can’t see the rudder.

And lots of water in the cockpit, is this a historical shot?
Allthough, can’t see any crew members on deck :wink:

Spot on Wolfgang :slight_smile: had the sheeting catch the shroud bolt and close-hauled caused the booms pull to the centre line of the boat … still finding my way with chambers.

Ah the crew !? fall washed over-board due to too much heeling and water coming into the cockpit :wink:

Hi Alan,
As usual, fantastic work ! Congratulations
According to my readings, I forgot where, the wave that is closing after the stern is not entirely negative.
When the water is going to recover the volume left by the passing boat, is also, in some way, producing a pushing force toward the stern and helping the sailing.
Pity that your cockpit is too open as such to get water in that produce some sinking other then the one induced by the sails down force.

Well, I saw that fern leaf at the hull and thought water in the cockpit wasn’t unusual in 2003 :wink:

To that camber/chamber issue, as you know I’m not that firm with (foreign language) nautical terms (I won’t say that lift-word again, but that’s another story :wink:

The term camber was a bit misleading, I saw the curve of the foot of the main and thought you are expecting some more waves. At the close hauled as shown in the picture, the gooseneck pivot offset should have flattened that curve a bit more. But I’m no sailmaker and can’t see the entire rig so I might be wrong on that.

So have a nice holiday and

Mast und Schotbruch

as we wish luck to the sailor in Germany :wink: