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1/4 tonners + the cup

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laser193713 View Drop Down
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Post Options Post Options   Quote laser193713 Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 09 at 11:38am

The rule for IOR is actually under 18.5 ft not anything to do with metric!

The whole point in the IRC rule is that we dont know how it works, but through trial and error sail makers and designers have managed to work out a few general formulas, the important thing though is that it is not a performance based handicap.  Unfortunately there is a measurment called "hull factor" which is a measure of the racyness of a yacht, in quarter tonners this seems to change a lot and is known to be a fudge factor that they use to performance equalise the boats. The ratings office would not agree of course.

If anyone is confused, a performance based handicap is one like in golf, where the skill of the player is equalised by their handicap, a measurement based handicap would take measurements such as the height and weight of the golfer and the clubs they used and give them an expected handicap.  This would favour the better golfers of course which may be a good thing, but it is much harder to please everyone with a measurment based handicap system.  People spend a lot more money to get their boats right on a system like IRC than a performance based system like PY, so the sailing industry prefers measurement based systems.

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alstorer View Drop Down
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Post Options Post Options   Quote alstorer Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 09 at 11:34am
As I understand it, one of the differences with IRC is that the formula used is NOT public, and that it also also revised quite often. Part of the idea is that whilst designers can make good guesses as to what will rate "better" (ie essentially create a boat faster than those on the same calculated rating) they should not be able to know for sure. I think it also essentially gives bonuses to features which improve seaworthiness and onboard comfort?
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Stefan Lloyd View Drop Down
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Post Options Post Options   Quote Stefan Lloyd Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 09 at 10:46am

Originally posted by craiggo

Basically these boats dont actually weigh 1/4, 1/2 or 1 ton but end up with an IOR length which is less than a given value for that class. From memory 1/4 ton IOR length was around 19m by the mid 80s. !

Eighteen feet in fact. The rating is just a number though: the boats were typically around 26 feet LOA.

 

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craiggo View Drop Down
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Post Options Post Options   Quote craiggo Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 09 at 10:24am
IOR and IRC are measurement based handicap schemes.

IOR was used extensively until the mid 80s but the current scheme used around the world is IRC.

IOR basically allowed you to calculate a length in ft which was then used to correct the boats elapsed time. From this several open classes formed ie, 1/4, 1/2 and 1 tonners. Basically these boats dont actually weigh 1/4, 1/2 or 1 ton but end up with an IOR length which is less than a given value for that class. From memory 1/4 ton IOR length was around 19ft by the mid 80s.

Unfortunately IOR created some strange designs, with hulls having large bumps to reach girth measurements and relying on lots of movable ballast, ie crew, to keep them going. The boats when measured had very low ballast ratio. Also the measurement was performed with the boat upright so large overhangs were used to gain waterline length when heeled. In the aftermath of the notorious Fastnet race, the IOR rule was heavily criticised for creating un-seaworthy boats, and some small mods to the rule were made during the 80s to try and sort this but the rule had already moved into decline.

IRC is the current measurement system in use, and I have to say I dont know exactly how the calcs are performed but it does seem to favour boats of a certain length. Ballast ratios seem high as do sail areas but I believe there has always been a 'fudge' factor applied by the ratings office which has often been the subject of much contriversy.

Anyway the re-born 1/4 ton cup is being run under IRC so many 1/4 tonners have been optimised with increased ballast (ie bulbed keels), fractional rigs with non overlapping headsails and larger spinnakers (area taken from the overlapping jibs).

The joy with any measurement based rule is that you can always optimise your boat to suit it, but it costs!!

Edited by craiggo
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Stefan Lloyd View Drop Down
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Post Options Post Options   Quote Stefan Lloyd Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 09 at 10:03am

IRC and IOR are/were measurement-based handicapping systems. There are around 8000 IRC certificates in issue worldwide and it's the main handicapping system in the UK for boats with beds. IOR was an alternative system that began in the 60s and died around the early 90s. Ton Cuppers were IOR boats built to a specific target IOR rating so they could race together without handicap - a concept somewhat like a development dinghy class. There has been a revival of the quarter-ton (around 26 foot) and half-ton (around 30 foot) classes for boats that previously had IOR ratings that made them eligible for those classes. However for reasons discussed elsewhere in this thread, they race today under IRC.  

 

Quarter tonners



Edited by Stefan Lloyd
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Pabs View Drop Down
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Post Options Post Options   Quote Pabs Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 09 at 9:02am
Okay for some one who is not massivly experianced in yachting but is intrested in and the idea of the 1/4 tonners can some one give me an idiots guide to IRC/IOR what they are how they work etc
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Stefan Lloyd View Drop Down
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Post Options Post Options   Quote Stefan Lloyd Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 09 at 4:35am
I remember Sergeant Pepper from the late 80s. A smart looking and fast boat! Have fun.
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laser193713 View Drop Down
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Post Options Post Options   Quote laser193713 Quote  Post ReplyReply Direct Link To This Post Posted: 03 Sep 09 at 5:55pm

You've completely missed the point! We bought our bolero almost by accident, we were looking for a sonata and while searching we came across the bolero.  The bolero was never designed to be competetive under 1/4 ton rating which is where boats like Purple Haze came from, she was an optimised bolero, smaller than standard with more sail and slightly different lines aft, not really a bolero as most seem to believe! That is beside the point though, our bolero was what was known as a Mk2, the difference being she has a lead keel, a small sugar scoop, an inboard engine and a slightly taller rig with jumpers and swept back spreaders (the standard bolero had a 3/4 swept back rig and an outboard with an iron keel).

Since buying the boat we have taken the inboard out becuase on a small boat IRC doesnt favour it. We replaced the old rudder with a new modern design because the old one was rotten and very very heavy! We have cut the scoop off the back to reduce overlaps now that the boat floats higher with 200kg of engine parts removed!

That was the end of our work on the boat until last years cowes week when we T-Boned runaway bus as they broached into us. We had some damage to the bow so while we got that fixed we also moved the forestay out to the bow from its previous position about a foot back. This gave us some extra fore triangle so we had enough room to make the genoa slightly smaller, turn it into a jib and sheet it inside the shrouds.  Doing this we went from 150% overlap to 115% which IRC also like.  We lost 2m of sail area from this which we added to our spinnaker and this allowed us a slightly longer pole for more projection because the SPL is a function of spinnaker area. Roughly 0.456 times the squareroot of the area.

For the price of some new sails and some patching up holes where engines used to go on top of the new rudder we have ended up with a much better boat to sail with much more room down below which is also faster around the windward leeward courses that we race on.  Fast enough to trouble the 50k boats at the top of the fleet at the quarter ton cup this year and finish in 9th overall. 

My advice if buying a 1/4 tonner is to either buy a really sorted one which should set you back no more than 20-25k and do nothing to it apart from buy new sails and sail the boat fast. Secondly you could buy a knackered old boat, the bigger ones tend to be more popular but just look for clean lines. Stick it in a shed, sand it back and strip everything out by hand.  All this should only have cost 7-8k.  Then spend the remaining 15k on a rig and a new rudder and some new paint.

Don't do what we did and buy a boat that someone had lovingly restored for cruising and then buy new sails for the old rig and then not have enough money for a new paint job and a new rig a year or so down the line!  You really have to take the time to get the boat right first time in the shed and then you can fiddle with it to make it faster.

As I have said though, most importantly look for a boat with clean lines, some of the boats had strange creases etc to make them fit the rule, perhaps these days the production boats that just happened to fit are a better bet because the lines may be cleaner.  Just a thought!

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JimC View Drop Down
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 03 Sep 09 at 2:24pm
Originally posted by detente

those that still are racing in the spriit of the quater ton class under IOR config??

Couldn't you argue though that a boat in a more IRC config is one that you can use every weekend, whereas one in an IOR config (which presumably means silly bow down trim, lumps and bumps etc) is one that would only be of use in a ton cup event or under Portsmouth Yardstick...
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MattK View Drop Down
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Post Options Post Options   Quote MattK Quote  Post ReplyReply Direct Link To This Post Posted: 03 Sep 09 at 12:47pm
This past weekend i was sailing a quarter tonner in my local yacht club
regatta, built by my dad in 1986, with original everything, even sails!
Unfortunately it was only ever raced of the club PY and never got an IOR
certificate so we cannot race in the cup even though it is an original and
more with the spirit of the rules than these moderised ones!
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