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DickDastardly

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  1. DD, having had a chance to put the Cookson 12 (Voodoo ex A cunning plan ex Blackadder) around the course a few more times it seems the thing's a rocketship under 10kts breeze, but struggles over 15kts (even with 850kg on the rail). Also I have q's about Assy v Syms on W/L courses...with a narrow waterline I get the impression a smaller Sym would be better.

    Before we start doing mods to chase handicap reduction, I'd value your thoughts on set up and next steps. Here's what I know:

    VooDoo                   1.136   Assy + sprit                     154m²

    Philosophers          1.138   Symm + Pole + sprit      138m²

    Grace O’Malley       1.130   Symm + Pole + sprit      140m² 

    Powerplay ??           1.130

    Avalanche                1.145   Symm + Pole + sprit     135m²

    I’m trying to find the IRC ratings for C12’s with short rigs:

    Sail Exchange (ex- About time)

    Occasional course Language

    Any input is valued - Cheers Couta

    1. DickDastardly

      DickDastardly

      Ha Ha!  Very welcome Andrew.  We're nice guys in this program.  We figure it'll pay us back.  When we bought Terra Firma (now About Time) we got a lot of help from the Melba community in giving us intel on the boat.  Have to say, we now know for sure that program was seriously dodgy on measurement...but that's a whole other story.

      One thing I forgot: remeasure the sails annually.  They shrink! 

      A couple of IRC certificates attached - the About Time one reflects the boat as it was when sold to Carl and renamed Sail Exchange.  Note the different hull factors, you should aim to get that as low as possible.  I'd say Pazazz HF is too high, can't recall whether that boat has an oven and a table, cushions etc, About Time did, very deliberately.  IRC rating is pretty sensitive to hull factor, and while Voodoo has plenty of visible carbon in the interior, as far as I am aware it's purely cosmetic and there's nothing tricky about the interior structure.  I'd be arguing politely but firmly with the IRC Rating office about that number if Voodoo HF is higher than 10.0 assuming it's fitted out as About Time was.

      Pazazz was re-weighed late 2014 after team About Time pointed out some strange anomalies (the 600kg delta I mentioned)  in the certificates to Rob Drury.  The IRC boat weight on the post-reweighing cert at 5072 is still 200kg above the ORCi displacement at that time (4864).  The freeboards must be screwy in ORCi, or the scale which weighed the boat in 2014 was massively out of calibration, or Rob was cheating and had more gear in the boat than allowed when it was weighed (I've known him over 15 years and that's very unlikely).  It's very important to check the ORCi and IRC displacements - they should be very close as the measurement conditions under the two rules are essentially the same. If they're not, ratings may be materially wrong.

      I see all the local C12s seem to have current ORCi certs so you can sharpen your rig and optimisation thinking using the data in there. 

      Comparing Voodoo and G.O righting moments, there's definitely something odd going on.  How could G.O be 150kg lighter than Voodoo, have 4mm less draft and have a 10% higher measured RM?  Makes no sense, the interior fitouts are pretty much the same (I've seen them both), keels are the same.  If Voodoo's rig is heavier that may explain things, but I suspect it's identical to G.O too.  That said, if the inclination done on Voodoo way back when came out assessing it with less than actual RM, expect a rating hit if it's re-done properly.  Sleeping dogs...

      Pre and post keel mod ORCi certificates for Pazazz are also available on the ORCi database for reference.  

      C12 Certs.zip

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  2. DD, having had a chance to put the Cookson 12 (Voodoo ex A cunning plan ex Blackadder) around the course a few more times it seems the thing's a rocketship under 10kts breeze, but struggles over 15kts (even with 850kg on the rail). Also I have q's about Assy v Syms on W/L courses...with a narrow waterline I get the impression a smaller Sym would be better.

    Before we start doing mods to chase handicap reduction, I'd value your thoughts on set up and next steps. Here's what I know:

    VooDoo                   1.136   Assy + sprit                     154m²

    Philosophers          1.138   Symm + Pole + sprit      138m²

    Grace O’Malley       1.130   Symm + Pole + sprit      140m² 

    Powerplay ??           1.130

    Avalanche                1.145   Symm + Pole + sprit     135m²

    I’m trying to find the IRC ratings for C12’s with short rigs:

    Sail Exchange (ex- About time)

    Occasional course Language

    Any input is valued - Cheers Couta

    1. DickDastardly

      DickDastardly

      Hi there - is it Hugh?  David Eastwood here.

      I navigated About Time and was in charge of data, polars etc. for 15 years.  The previous owner, Julian Farren-Price is very well tuned in to C12 modding of course and I'm sure he'd be happy to talk.  If you give me your contact details I'll ask him.  david.r.eastwood@gmail.com

      Net-net there's a major configuration difference between the earlier and later C12s.  SailExchange and OCL1 were built together in 2000, and were the last two built with the original cast lead IMS keel.  The later boats are more powered up with deeper steel fin / bulb keels and bigger rigs.  Unclear to me that this is actually an improvement as it's always seemed to me that they struggle a bit to sail fast enough to offset the big rating hit.

      I have relatively recent IRC certs for ex About Time, though all the detail you need is visible on the current ORCi Cert too - that's public domain and free of charge.  Go to ORC Sailor Services, set up an account (free) and search for Cookson 12 in boat type. 

      Shane Guanaria at Doyle Sails ran our sail program for many years and will also be a useful person to talk to. 

      At your rating you should be regularly hitting 7.3, maybe even 7.4 upwind in good breeze.  As you're new to the boat don't underestimate the experience factor, they are tweaky and no doubt you will sail it faster than you are now as you become more familiar with the boat!  850 is about what we carried on About Time when sailing 10-up (fat bastards...) so maybe even heavier would be worth thinking about?.  That said, not much room on the rail for another body...we sailed 9 up whenever it was light - medium.

      SailExchange rated 1.114 last I checked, OCL 1 a bit lower (has a heavier rig and motor than SailExchange).  You won't get Voodoo that low with the big keel and rig, however.  I'm guessing, but if you could get it down around 1.123, say, you'd be looking very competitive. IRC ratings are also public domain: https://www.ircrating.org/racing/on-line-tcc-listings  Not much detail data in there but download the complete spreadsheet and the right combination of length, beam, DLR and age date filters should pick up all the C12s currently rated worldwide.

      I'm reasonably familiar with Grace O'Malley as it was, having sailed it with the previous owner Rob Drury and having talked through modding the boat before their Hobart division win.  We delivered it back from Southport mid last year together and it was clear the drag from the deep keel and big bulb were very significant, it felt notably less slippery than About Time despite being allegedly lighter.  As a result he modded the keel, which seemed to work well.  Rob would have some views too, and I'm sure he'd be happy to share them.  Grace O'Malley is possibly not as light as its certificates suggest, I spotted some big measurement errors (e.g. 600kg discrepancy between IRC and ORCi displacements...) in that boat a few years back and it's unclear to me that they are entirely rectified yet.  Looking at its displacement, keel depth and righting moment together those three seem a little misaligned compared to other C12s.  It shouldn't be as stable as it measures in under ORCi at that displacement and keel depth.  Its interior isn't any lighter than any other C12.

      IMHO Sym kites are definitely the go on C12.  These boats aren't light or stable enough to really get up and boogie under an A-sail like say a Fast 40 or TP 52, but, sailing relatively fat angles under Symmetrics they can surf much earlier and better than IRC leadmines like Beneteaus etc, or even Sydney 38s, which gives them an advantage sailing under IRC/ORCi.  We were fully competitive with TP52s downwind until they started planing.

      The displacement on Sail Exchange's ORCi certificate is pretty close to the right number.  Within 30kg or so I'd guess.  We set it up with a short sprit for a Code 0 and long-ish pole (same length for measurement purposes) and that worked very well.  Our biggest kites were 132 sqm.  Code 0 was 80sqm and fractional, we made that call based on limited stability. We had a 125sqm A3 we flew off the little sprit but didn't use it much.  I understand that Carl Crafoord, current owner, is talking to Shane about a masthead zero for the boat.

      Years ago we reduced the main on About Time and detected no obvious drop off in light air performance so that's an option.  That said, we sail very well in the light, many crews don't, so that may be what offset the penalty.  If you can back yourself in that way then there's a potentially lucrative avenue.

      Do get the mast weighed if you want to race under ORCi, every bit helps!  The rig we put in About Time a couple of years ago is an absolute glamour, stiff as and weighs 156kg, around 20kg lighter than yours I'd be guessing.

      Peter Sorensen's boat, Philosophers, is moded very differently.  Has a massive bulb and is a lot heavier than most other C12s.  So far it's been unconvincing, and he's an excellent sailor with good crews.  Very fast upwind in any breeze, but pretty slow in light to medium airs and we were much faster downwind in About Time as we were a lot more slippery.

      We looked at About Time's configuration pretty much every season, and slowly optimised it over time, but were very focused on our program and aligning the boat's performance to the sort of racing and weather we expected.  We'd have moded it differently were we planning a Hobart tilt.  (That's what our new boat is for...) You probably ought to think through the program goal and its implactions for Voodoo mods, as there are plenty of options.

      Cheers

      David

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