That looks good until you do the wetted surface calc..;-) Interestingly, both had almost identical heel angles upwind...
Not significant compared to the higher weight. The AC120 was derived from the IOM specifications, especially for the appendages. The LOA of one is the LWL of the other with more possibility for the AC to reach higher relative speed when heeled. When running, the sail area difference should pay ! Loosing against a IOM is only possible if the tuning is bad or the fingers are not good ! Cheers ClaudioD
That said, it is a good yard stick. The Brit Pop has had incredible success, and I was chuffed to be in the same league! This is no ordinary IOM - designed as a low wetted surface, high wind performer, and we had no shortage of breeze. Also, just to mention the guys were very friendly, and I have an invite to his workshop to see production there
For a given displacement the lowest wet surface is provided by a circle. This is the only way to design it, as counterpart more heel since less lateral stability. In theory there are no secrets, one thing or the other ! A circled hull, in spite of less wet area, has higher draft hence more wave formation. Ciao ClaudioD
Probably because the AC120 is too heavy !!! Do You have the respective weight of IOM and AC120 ? ClaudioD
I'm a bit confused by the last statement... I was asking why has the Brip Pop been the IOM to beat. The weights for the IOM is 4000g and the IACC is 4512g..
4000g is the rules weight or the Brip Pop weight ? Thanks . 4512g is only 12g above minimum required and therefore perfect . Cheers ClaudioD
Hello Jim, first compliments for your boat: well made and beautiful looking. second: your sails setup on the pictures was very bad, the mainmast and the mainsail have two different curves, you have to work to find mainmast rigidity with the same mainsail shape. With this set-up where hard to sail upwind much more better than a very good IOM (downwind instead no problem, thanks to the 80dm2 sailsurface, and the major LWL). Just to knowledge, this is a old video with a race between my 120 and a very good skipper-IOM boat (inside first 10 boat of IOM italian championship). The 120 was my first SUI-100, launched on march 2008, she was my first boat made myself. Actual top 120 sails faster than this old SUI-100. http://www.youtube.com/watch?v=DFqauSVhYhA After a bad start (very bad first crossing) it is possible to watch the different boats performances with 4 knots wind speed. If the wind increses up to 10-12 knots the gap decreases. I started on 2007 my experience on model boats, recing for one year always against the IOMs of italian championship. It is a very good training. Cheers with the hope to sail a day together. Matthias
Thanks for the compliment, and yes the sails are passed their best I had them rigged on the yacht for quite a while before i dusted it off and it shows.. Your right in a way about the curve, I had almost max backstay as the wind was quite fresh, easily more than 12knts with some good gusts. Thats the overbend crease your seeing and its more pronounces because the material is super thin. Way thinner than anyone else is using. It's some cup stuff that I wanted to try. I was still able to sail as high and as fast as the IOM. If I left the helm alone she would overtake too. With the new mast that I have built, I will be needing a main with a different curve, so when I do get some time, I shall be back at the sail making. Cheers, Jim
My Little one, dry sailing already! I have only had enough time to build a new mast head crane, after I broke the last one whilst sailing in some gusty winds getting on to 20 knts... I have had to rethink the new mast experiment, as that one is a tad too thin, and whatever I try, will not stay in column... 4mm is too skinny for the sidewalls to cope with the compression. I am using UHMC (Ultra High Modulus Carbon) and I was hoping it would be able to resist, but no. Next one will have a taper, 4mm at the top, this time going out to 8 or 10mm at deck level. That should yeald a very stiff lower section with a bendy top, for auto de-powering the head. Jim