Showing my ignorance!

Allan

Allan

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I have seen some discriptions of boats on here and don't know what they mean. There are various classes known by weights, half tonners, one ton cup boats ect. They all seem much heavier than the weights. Some modern yachts are also refered to as AWBs. Can someone enlightern me?
Allan
 
Quarter, half, three quarter, ton etc, have absolutely nothing to do with weight (displacement) whatsoever.

They are purely a formula used for racing. ie a 'half tonner' complies with the half ton formula.

You probably don't need or want to know the precise details.
 
Quarter tonners, half tonners, etc. refer to complicated handicap formulae that gives totally different boats an equal opportunity of cheating when racing against one another.

Boats such as my 2 1/2 tonner (TM) refers to a medieval measurement of volume used to determine how many tuns of wine she can carry.
 
Thank you for the AWB answer (time to pick up the peices!). I am now fasinated to find out more about the tonners etc.
Allan
 
[ QUOTE ]
Thank you for the AWB answer (time to pick up the peices!). I am now fasinated to find out more about the tonners etc.
Allan

[/ QUOTE ]

And when you've done that check out the various "metre rules".
Honestly, wouldn't you rather be sailing?
 
There used to be racing cups awarded for quarter-tonners, half-tonners etc. Complicated formula to work out what boats fits which class, but 1/4-tonners were typically 24 ft long, half-tonners about 30/31 ft, 3/4 tonners about 34/35 ft and one-tonners about 39-40 ft. There were two-tonners as well Early designs to this racing rule often produced boats that made very good seaworthy, nice handling fast cruisers after a few years of racing life, later on the designers started tweaking hullforms to get rating advantages and produced some strange looking boats with dubious handling. Quarter tonners still race as a class, most of the others, if still raced, mostly race under handicap.
 
mini, quarter, half Tonners, 3/4 tonners, 1 tonners, 2 tonners & Maxis

These are all rating bands for boats designed under the IOR (International Offshore Rule) that was used from the early 70's until the late 80's to assess boats, give a handicap & allow boats to race against each other.

The rule specified a number of measurements to be taken from a boat and its rig (sail-plan), added additional corrections for items like the propeller and strut/shaft. These were all input to a formula, and the result was a number which was then used to create the Time correction factor (TMF). Multiply the elapsed time for a race by the TMF and you get the corrected time. lowest corrected time wins.

Ideal world: measure any boat, stick the numbers in the formula, race together and if all sailed equally well, the corrected times will be identical.

The rating bands (mini, quarter, half ton etc) were created to encourage similarly sized boats to be built and then race together in level rating regattas. In these regattas, boats also had to comply with the "green book" requirements which stipulated saftey equipment, max number of crew, minimum accommodation & equipment standards and other restrictions to try and give consistent performance between boats.
For each band/size a max rating (e.g. 22.5 ft for a 1/2 tonner) was set and the challenge was to create as fast a boat as possible that gave an IOR rating of 22.5ft or less when measured.

In its heyday, IOR created the prototypes for performance cruiser racers and was fantastic fun.

This simple rule eventually led to distortions and "type formed" hull shapes that were quite extreme. The rule makers would modify the rule each year to try and stay one step ahead of the designers who were trying to create performance improvements that minimised the handicap penalty.
you could change items (rig, sails etc) and get the boat re rated and there was a lot of skulduggery in the measurement process to ensure that you were rated to get a low rating.
The final boats created under this rule typically had:
v narrow waterline beam
v wide max beam
Small minimum sized coachroofs
spindly, multi spreader rigs with backstays, check stays and jumper struts
were expensive with a short competitive life
difficult to sail well
expensive as carbon, kevlar, nomex cores, etc were used to build them


Net net, the enthusiasm dropped and the rule died out to be replaced by the IMS system where a more complete virtual model of the hull was generated and a very complex series of TMF's used........binned after a few years as too complex.

So:
minitonners: IOR 18.0 (16-18ft 3-4 crew)
quarter tonners: IOR 20.5 (20-25ft 4 - 5 crew)
half tonners: IOR 22.5 (28 - 32 ft 5-7crew)
3/4 tonners: IOR 24 (35-38 ft 6 - 8 crew)
1 tonners IOR 27.5 then changed to 30.5 in 1982/3 (40 - 44ft 8-10 crew)
Maxis: 70" (80 - 85ft and 20 crew)
 
Allan,

it looks like everyone above has pretty much summed it up. I own a sail a Half Tonner out of Chichester. You can find more info on the half ton cup site http://www.halftonclass-europe.net/ they cover most of the half tonners, both production and 1 off. If you are looking to join the half ton sailers then you are more than welcome to come for a sail and try mine

regards

shaun
 
Don't forget the one raters & half raters! /forums/images/graemlins/grin.gif

12 meters, 6 meters, 3 meters. A hundred & one different measurement systems for silly racing rules! But some of the boat sproduced can be very pretty.
 
Re: cultural input

My Ben Lexen designed quarter tonner is 26 foot long and almost 10 feet wide. There is another Australian designed quarter tonner called the supersonic that is 27 foot long. The boats varied depending on where they are to be sailed. Fresher breezes, larger hulls smaller sails. Europe tended to have smaller hulls with larger sail area.
 
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