Hey Goose & Kiwi,
I must say that you guys up to date have done a fantastic job…put it this way!!! Good enough to make me now want to build one…I am from the Island of Bermuda and now living in Mid USA… I have done my fair share of sailing both pleasure and competition in Bermuda. I find your posts here very very helpful. I can’ wait to get started…I too will post pics of my build…
Best regards,
Danny
Hi All & hi Danny … wishing you best with your AC 120 build, a great project !
Today I popped the hull from the mold (compressed air gun) … perfect ! not a single blemish and she weighs in @ 231 grams !!! for my first hull I’m over the moon :zbeer:
Great K1,
12g less of what i was expecting and written some posts ago !! .
I’m curious, why the skin look white ?
Cheers
Claudio
Hey K1…
That’s awesome, well done mate! :zbeer:
My mold is wax ready and as soon as my pay comes in I should be in a position to lay up the hull this weekend 
Good question Claudio…
Welcome on board Danny… please do post your build progress. There are many experts here (not including me! :lol: ) to help you…
Cheers
Goose
Thanks guys, All components are from same manufacturer and reading technical data sheets says “Hardening 24-48 hrs” and “Hardening by Precipitation, 7 days” … no idea what that means, it makes no sense in English.
What should it look like ?
Hey K1…
Did you use epoxy or polyester?
Polyester can take a few days to setup based on the water percentage (evapouration) and maybe thats what your instructions are trying to say.
If you used epoxy, it generally dries clear to pale yellow and because it is a chemical reaction, generally doesnt need much time for a full cure.
Don’t worry mate, it all looks good and will be fine, the color is the only mystery.
Cheers
Goose
Hi guys
generally the epoxy take 24 hours for hadening, but the complete polymerisation will last at least one week depending on the albient temperature.
K1 and Goose you will see some more rigidity of the lamination in few days as the plymerisation go on.
Still I do not knows why is white !
I know instead that it is possible to mix with the resin a white powder called : Titanium Dioxide
This is an example of glass and clear epoxy :
Cheers
Claudio
The time is come to introduce some details concerning dimensionins and Fin Box and Mast support .
general view :
To note that in general as “rule of tumbs” the lead from the CLR may varies from 7% to 10% . Many parameters playing a role.
Actually I have "fixed " the lead with the CE/CV at 8% and the mast step position may varies as fonction of the Sail Plan and CE position. In the Drawing are marked some distances from 65 to 85mm measured from the rear side of the mast to the CE/CV ( CV is the French term staying fo Centre Velique)
The Sail Plan include a Mast rake of 1.5° .
Fin Box position, Mast support and servo plate:
details on Fin Box and Mast support including diagonal beam and shroud plates
Tipical Sail Plans : (the 78dm² is not reccomended at the beginning)
According to AC120 Rules , the minimum surface shall be 73dm² for rig tipe 1
Some pictures dscribing one Fin Box construction and appendages are on the AC33 discussion from page 12 onward.
Cheers
Claudio
Many thanks Claudio…
I don’t claim to understand all that, but I’m working my way through it… :graduate:
Cheers
Goose
Attention Claudio,
the second sail set is not in rules: the minimum surface for sail set 1 is 73dm2 (0,73m2)
Regards
Matthias
OK 72dm² Sail plan removed
Cheers
Claudio
Claudio thank you for the fin & mast box information, I’m seeking CF as per your manual along with IACC rules of 3000 gsm max weight for Fin & Bulb complete. Wanting to have the Keel fin as light as possible but strong enough to support the plan bulb weight 2,850 grams, means only have 150 grams to work with … a tough call my friend.
In regard to the sail plan, I have already ordered (from NZ sail maker) the 78 dm2 sail plan that is posted on the IAAC site (no others posted there, that I found) I understood from Matthias set 1 (78 dm2) is used in the wind range of 0-11 knots & set 2 (74 dm2) for wind range of 11-16 knots.
How much will the 78 dm2 sail plan affect my mast step position ?
Cheers K1
P.S Goose I’m using Epoxy
Claudio, I noticed the hull is flimsy and guessed it would become more rigid with time, are there planned to be any bulk heads (frames) in the hull, apart from the keel box and mast support ?
Cheers K1
Matthias,
In reading the IACC rules:
[i]Section F - Rig
F.2.2 CONSTRUCTION
The Mast shall have the Limit Marks inside which the LUFF of the main shall not be greater than 1750 mm. The Headsail Limit Mark shall correspond to 80% of the Main luff length. The forestay hooking will be fixed below the Limit Mark.[/i]
During the AC 33 build you showed a nice picture of your SUI 100 & Claudio had observered that the anchor point of your boat headsail is above the 80% main luff. I’m I right to understand that the forestay hooking refers to where the forestay meets the headsail & not the mast ?
Cheers K1
Kiwi,
the we use the set 1 (73-80 dm2) inside the range 0-11 knots, and the set 2 (up to 60dm2, not more) between 10-16 knots (but the wind limit to stop our regattas is more than 14 knots wind speed).
Attenction! The sail set 2 can’t be 74dm2 as you told! The maximum surface for set 2 is 60 dm2.
Regard your question:
See the attached image: it is the page 8 of IACC 120 Class Rules; it shows the exact meaning of 80%. I think it is much more clear than every my explanations.
It is not important where is the anchor point, but the ratio between Mainsail height and headsail height.
I hope now it is clear for you.
Nice Job Alan.
Some forms of epoxy have a toughnener or a Uv inhibitor added into the compound, both of these can result in a milky finish. You may have inadvertantly bought one of these types of epoxy. Its all good and an excellent result for your first build.
Gary
Hi K1
No specific bulkhheads are foreseen, only local glass or carbon reinforcementes, specifically in the area of the Fin Box, Mast support and Rudder.
Additional reinforcemente at deck level for the Mast support and on the Fin box side for two purposes :
a) lateral support for the Fin Box
b) servo winch mounting plate and Battery - Receiver plate
Cheers
Claudio
Hi,
All depends on the CE position of the full Sail Plan.
See Drawings above.
The reference point is the CLR, going forward, you adds the percentage of the LWL called “Lead” - in this case is 8% of 995mm = 79.5mm.
therefore the 79.5mm ahead of CLR (blue line) correspond to the vertical position of the CE (red arrow).
Now if you look to the Sail Plan (74dm²) you see that the CE is some 60mm behind the Mast, but getting down to the deck, this distance increases to 75mm because the Mast is tilted about 1.5° backward.
Thus, 75mm is the value to be taken into accout for the mast positioning on the deck.
Again, observing the above first drawing, it is easy to check the definitive distance of the mast from the stern or frame 12 : (the stern is always the starting point of all measurements)
539mm (CLR from stern) + 79.5mm (= 8%) + 75mm (CV on sail plan) = 693.5mm
Conclusion : the mast should be at 693.5mm from the stern.
On the drawing is marked 682mm that could be good for another sail plan with different sail ratios.
Obviously the Story do not End here, this is just the starting point to begin the Tuning phase, but will come back another day…
Cheers
Claudio
Hi Claudio, thanks for replying to my e-mail…and sending requested info…got it thanks…these guys are great (Goose & Kiwi…) deserve to be commended…I am so looking forward to getting started…
Danny
unless you are actually working on installing something in the hull - and if you used epoxy, I would strongly recommend keeping the glass hull placed back on the plug for storage. Otherwise it may have a tendency to slightly add a warp to itself. Perhaps too small to be seen, but no sense in taking a chance.
I lost a 48 inch /1.2 meter catamaran hull by leaving it off the plug. Just liked the look of it sitting on the overhead, and by time epoxy cured, and I started having deck measurement issues, it was too late. I had to add some foam bulkheads and duck tape to work surface to bring it back in line for deck to be added.
Because I didn’t trust it, my work on the one hull is now in a landfill here in Minnesota. Maybe 1,000 years from now someone will dig it up and use it? 