Handicapping systems for ocean racing yachts

J. N. Newman

December 1974

Note: _{This is the draft of}

a paper to be presented to the Royal Institution of Naval Architects 20 March 1975

meeting in Southampton, _England.

Printed copies of

the paper are to be published _{by the Royal Institution}

of Naval Architects, 10 _{Upper Belgrave Street,}

London

SWÎX 8BQ.

This research was carried out under the North American

Yacht Racing Union Ocean _{Race Handicapping Project, M.I.T.}

OSP Project No. 81535.

The generous support of the individual

donors to this program is _{gratefully acknowledged.}

Handicapping Systems for Ocean Racing Yachts

by J. N. Newman, _{N.Sc,, Sc.D. *(Feilow)}

*professor of Naval

Architecture, M.I.T., _{Cambridge, ?fass., U.S.A.}

Suwznary: _{Several aspects of}

Ocean race handicapping

are discussed

from a viewpoint _{based on the}

present state-of-the_art of ship

hydrodynamics. _{A model for}

speed-prediction is

described which relies _UPOfl

towing-tank data for the hull forces, these being balanced

with the sail forces by a suitable _computer

programme.

A comparison is made of several existing _and

hypothet-ical time_allowance _{systems, in conjuñctjon}

with the IOR Mark _III

rating rule and

race statistics from _{twenty-one recent races.}

An

alternative multiple-rating _{system is illustrated,}

which is based

upon separate considerations _{of sail area and}

hull length, in an

integrated rating-rule and time-allowance _system.

The results of

this proposed scheme _{are compared with te}

IOR Mark III and _{with the}

expected performance of _{different yachts based}

upon the

speed-predic-tion Programme. _{Finally, some}

nonhydrodynamic _{aspects are discussed,}

with emphasis _{on those areas of}

rating-rule development _and

adminis-tration which _{can be aided by more}

Sir,

At the beginning of _{another season, I would}

wish to suggest

to. those interested

the advisability of totally abolishing

handicapping, which has had _{the effect of ruining}

yachting in

Sydney and entirely putting a stop to yacht _{building. The}

system of time alloqance

for tonnage, as at present calculated,

gives rise to

constant disputes, and has caused yachts to be

built expressly to avoid it in every possible way.*

*(From a letter pUblished _{in the 'Town and Country}

Journal', Sydney,

20th July 1872. _{Reprinted in 'Sydney}

Sails - The Royal Sydney Yacht

Squadron 1862-1962', _{page 63.)}

1. _Introduction

For more than a _{century, yachtsmen and naval}

architects have

sought to handicap sailing yachts so that _{'equitable racing might}

take place between vessels of different size _{and type. A recent}

historical outline of this subject is given by _{Strobmeier (Ref. 1).}

Technical progress has been made more-or-less _{continually, but}

devel-opments in handicapping have _{been outpaced generally}

by the parallel

efforts of designers and builders to develop _{new boats within the}

framework of the current rules.

The growth of ocean racing in the

past two decades has intensified _this

_problem

and has focused

atten-tion as never before _{on the difficulties of}

equitable handicapping.

Historically, the handicapping _{problem has been divided}

into two

distinct parts, the determination of the boat's

_rating,

and the time...

allowance formula

by which handicaps _{are computed for a given}

race

from this rating. _{Since 1970 a}

couon rating rule, the _{International}

Offshore Rule (bR), has been used throughout _{the world, but different}

countries and yachting _{organizations have continued}

time-allowance formulae. _{A notable exception to this binary}

system

is the advent of

level-class racing, where boats of equal _{rating corn-.}

pete without time allowance,

as a separate class or in _{special races.}

Level-class racing Ms

obvious advantages, _{notably that time}

allow-ances do _{not become a factor In}

the race, but problems and questions

associated with the rating _{rule will affect}

level-class racing to

the same extent, _{or even more than is}

true fàr conventional ocean

racing with time _allowances

Two years ago, in response to an invitation from

the HISWA to

present a paper to their _{Symposium on Yacht}

Architecture (Ref. 2),

the author developed _{a critique of current handicap}

systems, and

suggestions for future

developments in this field based on the _present

state-of-the-art in nava]. _{architecture and the related}

fields of

aerodynamics and applied _mechanics.

The scope of this task _{was broad,}

for in the field of

ocean-race handicapping virtually no research and

development work had been done, by the usual _{standards of contemporary}

engineering and technology.

The engineering

disciplines that _{could be applied seem to fall}

logically into _{certain categories.}

One is the _{application of ship}

hydrodynamics and aerodynamics, to predict _{the performance}

of

given boats in hypothetjca _{race conditions,}

so that variations

of boat size and

type, and of race conditions, _{can be rationally}

predicted and used _{to guide the handicapping}

process. _Another

is the utiljtj0

of numerical _{analysis techniques in the}

devel-opment of rating rules

and measurement of yachts, _{so that the}

ac-curacy of the final _{rating will be}

to small measurement errors. _{Yet another category is the}

use of

digital computers and statistical procedures to analyse _existing

rating certificates and _{race data, on a sufficiently large}

scale

that the inherent _{Inconsistencies of this data}

are accounted for.

Finally, by utilising _{computer lines-fairjng capabilities,}

much

more information can be gained about _{a given hull form without}

ïn-creasing the _{measurement effort.}

The necessary financial investment to achieve these _capabilities

is not insignificant, _{but should be weighed against}

the present level

of investment, whIch is on the order of £1-million for _measurement

costs alone. _{Looked at in this light, and}

without consideration of

the much greater capital _{Investment in yachts designed}

to the current

rule, it is obvious that

research in this field will be _{cost-effective}

from the standpoint of _{the yachtsmen involved.}

The response to the critique and suggestions contained _{in Ref. 2}

was unexpectedly enthusiastic, and _{In the interim an organized research}

prograe has been initiated at MIT _{with financial support}

organized

by the North American Yacht _{Racing Union (NAYRU).}

At the same time

this programme _{was being launched, the author presented an up-dated}

version of Ref. 2 to the 28th November 1973 meeting of the _RINA

Aus-tralian Branch in Sydney (Ref.3). _{The present paper is intended}

to

develop further some of the ideas which were presented _{in a preliminary}

fashion In Refs. 2 and 3, _{taking advantage of the research effort now}

under way in the NAYRU/NIT _{research programme. A general}

but

be given, with emphasis upon two special topics, the _{comparison of}

different time-allowance systems using actual _{race statistics, and the}

development of a 'multiple-rating'

formula wherein different parameters

of a yacht such as its sail area and length _{are treated separately}

instead of being integrated _{into a single rating number.}

2. _{The NAYRU/MIT Research}

Project

Ocean-race handicapping has many facets, which must be _{studied and}

developed simultaneously _{to ensure a successful}

system. In principle,

the basic handicapping _{formulae may be derived}

from hypothetical

per-formance predictions determined by hydrodynamic _{and aerodynamic theories,}

but these are incomplete and must be supplemented _{or replaced by empirical}

data from towing-tank

tests, performance testing of _{full-scale vessels,}

and from existing _{race data.}

Since none of these inputs _{are sufficient}

by themselves, it is _{necessary to utilise all of them}

in concert, and

to test the resulting handicap

formulae against existing _{race data and}

boats. _{Finally, the administration of any successful handicapping}

system

requires special instruments _{and techn±queá for measuring}

boats, and

computer programmes for reducing

this data and checking for measurement errors.

These different facets and interrelationships are illustrated _in

Fig. 1, which shows the sub-division of planning _{for the NAYRU/MIT}

research project on _{ocean-race handicapping.}

Three basic _{corner-stones}

are the handicap system itself,

the data bank of boat ratings and race data, and the performance

prediction system used to predict _hypothetical

boat performance. _{These three parts of the overall project}

by circles, and joined by inter-active _{arrows representing the}

utili-sation of each member to develop the _otiers.

Basic inputs to each of

these, indicated in the Figure by rectangular _{elements, include boat}

ratings and race data,

_which

_{make up the data bank;}

performance tests, theory and tank tests,

which are utilised in the performance prediction

system; and measuring _{tools, lines-f airing}

programmes, and a data bank of hull lines used

for administering and testing the handicap

systems _{and for secondary purposes such as the design of}

towing-tank

models. _{A final element of Fig.}

1 is the output, in the form of a

handicap system or systems to be used and evaluated by _{race conunittees}

and by the yachtsmen _themselves.

The NAYRU/MIT research project was initiated a year ago, and work to date has been

concentrated on the development of the _{data bank,}

per-formance prediction systems and a càmputer lines-fairing

programme, with

some preliminary studies based upon these which will be described _in

the following Sections. _{Among the more outstanding}

subjects where further

inputs are required are the acquisition of further _{race data, performance}

tests, and tank tests, and the development of measuring _{techniques and}

instrumentation for measuring _{hull offsets.}

3. _{The Performance Prediction System}

Predictions of the relative

performance of different boats are

essential to the development of

any handicapping system. _{These predictions}

may be the result of bar-room speculation,or of more _systematic

obser-vations and statistical analysis of existing _{race results, but in either}

design practice, as influenced by present and past _rating-rule

develop-ments. _{Historically, this approach has}

been satisfactory for

handi-capping existing boats, but has generally been susceptible _{to exploitation}

by new designs.

To take a more fundamental viewpoint, one can predict the _equilibrium

speed of a sailing yacht from _{a quantitative analysis of the hydrodynamic}

forces acting on the hull and the opposing aerodynamic _{forces acting on}

the sails.

This latter approach has been used with notable success by

yacht designers, for the past forty years, to develop yachts _from

towing-tank tests, but it has been almost completely ignored in _{the development}

of handicap systems. _{Indeed, Froude's hypothesis}

is ideally suited to

predicting the effects of length _{on performance, and specialists in ship}

resistance will be relieved by the minimal Importance of scale effects

involved in relating hull lengths between, say, twenty and _{sixty feet.}

In Refs.. 2 and 3 _{a simplified analysis was outlined}

for

pre-dicting boat speed from a consideration of the longitudinal _{hull drag}

and sail driving forces, without _{regard for the side .forces}

and heel

moments. _{Recent work (Ref s. 4 and 5) has led}

to the development of

a more complete analysis, including _{the side force}

and

heel moment _{as well as the hull drag and}

longitudinal sail force.

The procedure for obtaining _{and balancing these is outlined}

below,

and further details _{may be found in Ref s. 4 and 5.}

Basic inputs required for the hull are the upright (zero heel

and leeway) drag coefficient,

generally obtained from towing _tank

heel angle and for the _{induced drag associated}

with a non-zero side _force.

The heeling moment is _{assumed to be hydrostatic}

and linear, and is

determined from the heel angle and static heeling _{moment coefficient.}

A slight simplification

results by taking the side _{force, rather}

than the leeway angle, _{as the parameter affecting the}

induced drag

component, thus reducing by one the number of unknowns in _{the problem.}

Froude's scaling procedure, _{in Conjunction with}

the ITTC frictional

drag coefficient, is used to obtain full-scale _{hull forces for}

geosim

hulls of different lengths, _{in the manner outlined}

in Ref s. 2 and 3.

The corresponding aerodynamic forces for the _{sails are derived}

from full-scale performance tests with _{carefully instrumented}

yachts,

based on measurements of the boat and wind _{speeds, heel angle, and}

apparent wind angle.

Towing tank predictions of the hull forces in

the same sailing _{conditions are then utilised}

to determine the equal

and opposite sail forces _{in the full-scale}

conditions. _{Thus, in effect,}

the hull is used _{as a transducer to measure the sail forces during}

actual sailing conditions.

This procedure has been _{adopted after}

careful consideration of _{alternatives, including}

theoretical predictions

of sail forces (which are restricted to close-hauled _{sailing conditions,}

and which have been used here to estimate the _{vertical elevation of the}

effective center of the sail forces). _{Wind tunnel}

measurements of sail forces are another

alternative, but the wind _{tunnel must be}

extremely large relative

to the model, to avoid serious blockage effects,

particularly during reaching _{and running Conditions,}

and an additionnl

problem is the need to represent at model scale _{the subtle shape of}

apparent wind velocity.

This assumption permits _{the same coefficients}

to be utilised for

other wind speeds, and _{for rigs of different}

size, and hence also

for boats of different _size.

However the sail-force _coefficients

will depend on rig geometry, e.g. the aspect _{ratio and relative size}

of foretriangle, _{to say nothing of two-masted sail plans.}

These

effects can only be ascertained by carrying out _{performance tests}

with a variety of different boats having _{representative sail plans.}

To date, sail-force

coefficients have been obtained _{in this manner}

for only one ocean racer, the sloop BAY _{BEA, during the relatively}

light-air conditions of the 1974 Southern Ocean Racing _{Circuit (Ref. 4).}

It is hoped in the near future to obtain further data

for this boat

as well as others with _{different rig geometries,}

thus extending the

performance prediction capabilities on which the _{development and}

The 'velocity prediction

programme' (VPP) takes the _{above inputs,}

for the hull and rig _{in question, and}

determines through _{a process}

of iteration the equilibrium boat speed and _{heel angle for each}

prescribed true wind speed _{and direction.}

Heel angles are _restricted

to 30 degrees by 11reefing" the sails; _hi

is accomplished by a simple reduction in sail area, with a proportionate

reduction of the sail forces and moment arm.

This process of force reduction may correspo1

in practice to _{flattening sails or chaning headsails,}

as well as to

actual reef ing.

Preliminary results from the VPP progralmne _{are shown in Figs.}

2-5, based on the BAY BEA. hull and rig, _{and geosim Variations}

of

these, for true wind _{velocities between 5 and}

30 knots. _Boat

water-line lengths of 20, _{30, 45, and 60 feet}

are illustrated. _{Figure 2}

shows the predicted _{performance for a beat,}

at the optimum heading

angle to maximise speed made good to windward. _{In this Figure the}

reefed condjtjos are apparent from the (horizontal) _{curves of speed}

vs. sail area, where increased

sail area does not result _{in increased}

speed. _{These results might be questioned since}

they indicate not only

a 20 footer but also _{a 30 footer reef ing in}

a true wind speed of ten

knots, and a 60 _{footer reefing in 15 knots.}

However, several limi-tations must be noted in this connection.

Also the SORC BAY _{BEA performance data} were obtained exclusively in light to moderate

wind conditions, in which the sails were relatively

full. In any event the above true wind speeds will correspond

to substantially, larger apparent wind speeds,

so that the disparity with

actual sailing experience is not large. Figure 3 shows

corresponding predictions of _{boat speed for a}

reach, with a true wind

direction of 100 degrees _{aft from the bow.}

Here the importance of _{a, large rig in light air is apparent,}

espe-cially for the larger _{boats where the five}

knot wind is _Particularly

light.

Figure 4 shows results _{for running, defined as a true wind}

angle of 170 degrees, from the bow. _{In this case the form of the}

speed curves is very different, by comparison _{with a beat and reach,}

as anticipated in the simplified

analysis of Refs. 2 and _{3. In light}

air all boats are limited _{by the reduction of}

apparent wind velocity

with increasing boat speed, so that a large _{sail area or hull length}

is relatively unimportant _{in light air, whereas}

in stronger winds both

are extremely important. _{Two effects which}

are neglected in our

anal-ysis are problems of

directional stability and _{control (e.g., broaching)}

with corresponding limitations of sail _{area and boat speed, and also}

the effects of surfing in _{following seas.}

Hopefully these two effects

may tend in general to cancel _{each other.}

Finally, _{Figure 5 shows the}

results of averaging the

above three _{sailing conditions for a}

race consisting in

large, these

average results are as might be expected from _the

pre-ceding figures, and _{for general}

purposes this is the most _relevant

set of results to _{use in handicapping}

round-the-buoys races. On the

other hand, Figures 2-4 may be used to evaluate

special-purpose

handi-cap systems applicable to _{particular point-to-point}

racing conditions.

Similar analyses _{and predictions of}

boat performance _{can be}

made for other hull _{shapes, and}

for changes in rig _geometry.

Variations of rig _{geometry may be included}

by making full-scale

per-formance tests for _{other yachts,}

as noted above. _{The effects of}

varying hull form are to be assessed from

a systematic series of

towing-tank measurements, _{derived from a}

research programme now in

progress at the Delf t

Shipbuilding Laboratory and based on _a

Maas-designed Standfast 43 _{foot parent hull form.}

By proceeding in _this

man-ner, it is hoped to

rationally predict the _{performance of widely}

different hull shapes and rigs, as _{a basis for evaluating}

the

var-ious factors of the _{rating rule.}

4. _{Existing Handicap}

Systems and Race Statistics

Simply stated, the problem of ocean

race handicapping is to

determine the results _{of a race over}

a prescribed course _involving

yachts of different, size and type. _{If each boat finishes}

the race

in an elapsed time E , the usual procedure is to 'correct'

this

time with a suitable

formula, the most general, being

C=AE+BD

. (1)

Here C _{is. the corrected time, on which the}

final race results are

based, D _{is the distance of}

nautical miles, and the _{coefficients A and B}

are intended to

represent the speed-potential of each boat in the _{race. Two special}

cases of (1) are the _{time-on-time formula,}

C=A.E

(2)

where B = O _{and handicaps are}

proportional to the elapsed time,

and the time-on-distance _formula,

E + BD

(3) where A = 1.0 _{and handicaps}

are proportional to the _{race distance.}

The latter is used most commonly in North America, _{whereas the}

time-on-time approach is _{customary elsewhere including}

the U.K. A notable

exception was the use in British

races in 1973-74 of a 'performance

factor system' of the _{more general form (1).}

In order to relate ultimately the _{parameters A and B}

to the

speed-potential of each boat, _{it is convenient}

to rewrite (1) in the form

V=D/E

A

C/D-B

(4)

where V _{is the velocity}

of éach boat, and _{D/C = V its corrected}

velocity. _{Ideally V}

should be the _{same for all boats in}

a given race, indicating

a dead heat and hence a perfect handicapping _system,

all other variables _{being equal.}

Nevertheless, V will vary from

one race to another, dependent

on race conditions and the _{overall speed}

of the race. _{Thus equation (4)}

contains one descriptor _{(CID) of}

the race conditions, and two parameters _(A,B)

dependent upon the speed-potential of each boat

but assumed independent of the race

conditions. _{The handicapping}

the functional dependence of A and B _{upon boat size and type,}

such that (4) best

represents the speed-potential of each boat in

the race, over a range of anticipated race speeds V . Two

al-ternative approaches to this _{problem are, firsts to predict the}

speed performance of each boat

from available hydro- and

aero-dynamic knowledge, following _{the procedures outlined in Section 3}

above, and use this prediction _{to determine A and}

B or,

al-ternatively, to proceed _{empirically with assumed functions}

of the

parameters describing each yacht, _{testing these against actual race}

statistics.

Existing race statistics form _{a large, and relatively untapped,}

source of potential information by which to judge existing

handi-cap systems or develop new _ones.

Indeed, if the race _{results are}

sufficiently 'fair', and representative of the potential _performance

of the fleet, and if the fleet _{is sufficiently diverse in}

size and

type, then one might envisage using the race results with _{a suitable}

regression analysis to develop new rating rules and time-allowance

formulae. In practice, however, these _{conditions are not}

sat-isfied, and the most which one can exec1 from an analysis of _race

data is to use it to judge

the fairness of proposed time-allowance

formulae, and of those particular features of the rating rule where there is a representative

spread of the parameters in question among

boats in the fleet which _{are otherwise performing equally.}

To date,

we have used race results for the former purpose

only, to test proposed and _existing

systems in conjunction with the

bR.

_{This work will be described}

briefly.

Twenty-one races from the last two years have been _{used as the}

basis for a study of

eight different time-allowance systems. The

races include several major _{races held in the United}

States and in

England, and one _{Sydney-Hobart Race.}

In ali cases it _{was felt that}

the fleet _{was of}

sufficient size and quality to ensure

validity of the _{conclusions which might}

result. _{No attempt was}

made to exclude 'unusual' _races,

on the basis that desirable

handi-capping systems should ideally perform for _{these as well as the more}

normal conditions.

The eight different

time-allowance systems which _{have been}

examined are listed in Table I, with the

corresponding coefficients

A and

B

as defined by equation (1), and the corresponding _assumed

velocity equation (4). _{Two of these formulae are of the}

time-on-distance (TOD) form,

including the NAYRU system which is currently

used for virtually all American races, albeit _{in some cases with}

a

modified constant or _{(equivalently) a modified race distance}

D

For example, in the 1974 Bermuda Race the _{constant 0.6 was replaced}

by 0.55, corresponding _{to an effective reduction}

of the rhumb line

race distance from 635 _{to 582 nautical miles.}

The second

time-on-distance formula is that which has been used _{on occasion by the RORC.}

The third formula is the RORC Performance

Factor System, used in

1973-74, which is of _{the time-and-distance}

form. _{The remaining five}

time-on-time (TOT) formulae

include a proposed Cruising Yacht Club

of Australia (CYCA) _formula

in 1973-74, the former _{RORC formula, a modified RORC formula (RORC2),} and a time-on-time formula

originally suggested by the _{author denoted}

as NAYRU TOT

because it is based upon the same velocity equation as the NAYRU

time-on-distance formula. _{The NAYRU TOT formula}

bas taken on added interest since it has been _{adopted by the RORC}

for use during the forthcoming seasonY

These eight time-allowance _{formulae bave been applied}

simultan-eously to the elapsed times of all boats competing in _{the twenty-one}

races noted above.

Corrected times for each race, boat, and

time-allowance system have been _{converted to corrected velocities,}

by

dividing the corrected _{time into the (nominal)}

race distance, so

that the results of _{different races could be}

more easily compared.

As an illustrative

example, Figures 6-8 show, the computer output from the 1973 Fastnet Race.

Figure 6 gives a listing of part of Class I,

with columns for the name of boat, class, rating, and _{the fleet position}

followed by corrected _{velocity, for each of}

the eight time-allowance

systems. _{The last column shows the}

elapsed time. _{Figure 7 shows}

the elapsed (actual) _{velocities for the entire}

fleet, plotted vs.

rating.

This type of plot is useful for judging the _{nature of the}

race, and serves to illustrate

some typical problems which _arise.

First we note that there _{is a predominance of}

boats in the rating

range between 21 and 40 feet, and these'

smaller boats are generally

closer in terms of

performance as well, so that the density of boat

speed vs. rating changes _{markedly as the rating}

increases. _Secondly

we note that there are two

Outstanding performers relative _{to the}

*

Roic

fleet as a whole, _{which from Figure 6 can be identified}

as SAGA and

RECLUTTA III, but it may be anticipated that the _{winner, between}

these two competitors, _{will be sensitive}

to the particular handi-capping system employed.

This problem is confirmed by the tabulation

in Figure 6, and by _{the corresponding plots}

of corrected velocity in Figure 8, which

facilitate relative judgement of each of the _eight

handicap systems.

One unusual feature to be noted in these _{plots is the tendency}

of most boats to finish in four distinct _{groups, with elapsed}

velocities independent of rating as indicated by _{the.horizontaj}

arrays of points in Figure 7. _{These four groups differ}

in. elapsed

times by approximately 12 hours, and are obviously _{correlated with}

the tide as a _{consequence of the light air}

experienced at the finish

of the 1973 Fastnet _Race.

In order to _{compare the eight time-allowance}

systems on an

objective basis, _{numerica]. figures of merit have}

been derived equal

to the slopes of linear

corrected velocities. _{A positive s1op}

izdicates that the larger

boats are favoured, _{and vice versa, the}

ideal slope being _zero.

Four different least-squares

procedures hàve been utilised _including

(1) a conventional

least-squares fit, with each boat in the fleet

given equal weight, (2)

a least-squares fit where _{the winner carries}

the mast weight in determining the _{straight-line slope,}

_an4

the

weights are reduced linearly _{down to the bottom of}

the fleet, (3)

a least-squares fit to the

top half of the fleet only, the cut-off

being the median _{corrected velocity of the}

fleet, and (4) _{a similar}

fit, but with the cut-off taken as the

straight-line fit defined by

(1) above. _{The slopes of these lines}

are tabulated in Table II for

the 1973 Fastnet Race. _{Comparison of these four figures}

of merit

for twenty-one _separate

races indicates that the choice _among

them is not critical, when

they are averaged over a number of races.

Figure of merit number _{two (weighting proportional to fleet}

position) has been judged

the best of the four, for comparative

purposes, and the corresponding

least-rsquares straight lines are

dis-played in Figure 8 for each time-allowance _system.

Note that the

slopes of these lines _{are the corresponding figures}

of merit, a

hori-zontal line with _{zero slope being regarded}

as indicative of uniform

fleet performance and hence an optimum _{time-allowance system.}

Table III

gives a tabulation of figure of merit two for each _{of eight}

time-allowance _{systems and twenty-one}

races, as well as the mean values

of the magnitudes of _{this figure of merit for ail races.}

rather than algebraic _{means, are used hers}

on the presumption that

favouring either end of _{the fleet is equally}

Undesirable, and a formula

which alternately favours _{large and sma'l boats}

in different races should not have this

alternation cancelling out.

For all twenty-one _{races as a group, the}

time-on-time systems

are best, the lowest figure

of merit being .0162 _{for the CYCA formula,}

followed by .0170 for _{the NAYRtJ time-on-time.}

The time-on-distance

formulae are intermediate, and the PFS _{system has the worst figure}

of merit value of .0246.

However, when the races are separated out

by country interesting

differences appear, with

time-on-time superior

in British _{races and time-on-distance}

superior for American _races.

This is a convenient _{result, since it}

confirms the traditional _decisions

of national yachting _{organizations in both}

countries I

These figures of merit may be used for

comparative purposes,

but they should be

considered reliable with a tolerance of perhaps

five or even ten _{percent. Thus the relatively}

small differences that exist between, for

example, the CYCA, RORC2, _{and NAYRU}

time-on-time formulae may be _{of doubtful significance,}

Particularly since

one could optimize the _{coefficients of any}

one for this particular

figure of merit, _{so as to improve its}

performance. As an illustration

of this fact we show in Fig. 9 the figures of merit for

modified NAYRIJ _{time-on-time formulae,}

in which the _coefficient

0.057 is _{changed to a range}

of other values, and in Fig. 10

the _{corresponding results}

for the NAYRU _{time-on-distance formula}

There are significant

differences between British and American

races, as indicated both by Table III and by _{Figs. 9-10.}

Figs. 9

and 10 show not only _{the better performante}

of the NAYRU

time-on-distance formula for American races, by _{comparison to the UK, but}

also show that the optimum values of the

coefficients in both time-on-time atd time-on-distance

formulae take _{significantly different}

values on the opposite sides of the _{Atlantic, as indicated}

by the

points at which the

curves in these Figures are minimized. _{For the}

time-on-distance formula, Fig. _{10 shows that 0.6 is}

nearly optimum

for the US _{races, but 0.8 is}

more appropriate for British _races.

For time-on-time _{Fig. 9 shows that}

the minimum occurs at 0.01 for

UK races and 0.09 for _{US races.}

While various _{explanations may be}

offered for these differences, and all

conclusions should be qualified

by the limited _{number of races involved}

in this study, it appears to

the author that in British races the entire _{fleet sails at nearly}

the

same speed-length ratio in each race, whereas

in the US there is a

greater difference _{between the}

speed-length ratios of large _{and small}

boats in a given _fleet.

Ultimately, it would seem that a time-and-distance

formula

should be more flexible _{than either special}

case, simply from the viewpoint that by depending

on two inputs, rather than _{one, it must}

work better. _{The PFS system}

tends to dispute this _{view, but lt}

may be that with

more development a greatly

improved time-and_distance system will evolve, and lt Is hoped that _{efforts in this}

direction will not be discouraged on either _{side of the Atlantic.}

But it is also clear _{that we should}

not strive for a

_COon

time-allowance formula for

conditions and in perfprznance _{of the different}

time-allowance Systems

are clearly implied by Table III _{and Figs. 9-10. (In this connection,}

it is amusing to recall that _{the CYCA fQrmula was devised entirely on}

the basis of rather

specialized race satjstjcs from Sydney, with no

suggestion that it should be _{very useful elsewhere.}

Our results

indicate that this limitation _{is more àpparent than real.)}

The complete results of _{this analysis are included in}

Ref. 6,

and further race _{statistics are to be studied in}

the future.

5. _{Multiple-Rating Systems}

As has been noted in _{the Introduction,}

existing handicap

sys-tems are divided into two separate parts, _{consisting of a rating}

rule which determines for each boat its rating R , _{and a}

time-allowance formula which

determines for each rating _{and a given race}

the corrected time of the boat.

By assumption the rating symbolizes

the speed-potential _{of the boat in question, and this single}

para-meter is in

essence an, integration of the _{very different effects}

on

performance of the hufl _{length, sail area,}

aspect ratio or rig

geom-etry, displacement,

stability, and various other factors. _Clearly,

this lumping together

of different facets is unrealistic, _except

under a hypothetical _{average condition.'}

In Refs. 2 and 3 it

was pointed out that _greater

flexibility of handicapping _systems

could result if multiple ratings are adâpted, _{in which the different}

parameters of the boat would _{affect its handicap}

to different degrees

in different conditions. _{As a relatively obvious}

a boat with a large rig will _{clearly benefit in light}

air, but will

suffer in heavy wind conditions, by comparison _{to a boat with larger}

hull and smaller sail area.

A very simple multiple-rating

system was suggested in Ref. ₃

to illustrate the potential, of this _approach.

This method of

handi-capping has been developed further, within _{the context of the IOR}

Rating Rule, but treating _{the length L}

and sail area S _{as two}

independent factors. (Here L is the IOR determined _{length, which}

corresponds approximately to the LWL _{length, and S is the IOR}

rated sail area, which _{for contemporary sloop}

rigs exceeds the _geometric

area of the mainsail

and foretriangj,e by about 20%.) _{Our procedure}

is to treat the _{coefficients A and}

B in the corrected

time formula (1) _{as independent functions of}

the two parameters s

and L , and search for functions _{which realistically}

represent the

the performance of the boat for a _{range of hull lengths and}

sail areas. In the process of doing

this the IOR Rating Rule and NAYRIJ

time-on-distance formula have been _{regarded as a base.}

The multiple-rating

formulae we have studied _{are of the fórm}

A = 1.0 + y(s/s0 _{- 1)}

B =

A{L1/2 -

_{L_h/2[l.0}

+

Here S0 _{is the sail area of the base boat for each}

length (i.e.

L5 is the scratch L , taken as 30 feet, and (y,A,rS) are

parameters chosen by comparison to the VPP results and listed in

Table IV.

Figures 11-14 show a comparison of the expected _performance

of different boats _{according to this multiple-rating}

system, along

with the performance expected by the single-rating _{system based on}

the IOR III Rating Raie and NAYRIJ

time-on-distance time-allowance system, and both, are compared with

the predicted performance based _on

the VPP/BAY BEA results of Figures 2-5. _{Here, to avoid confusion,}

only the true wind speeds of _{5,10,15 and 30 knots are Shown.}

In general,

the performance demanded by the multiple-rating System is closer to

that predicted by the VPP programe, a fact which. is attr:thutable _{in part}

to the flexibility of the multiple-rating

system, by comparison with

the single-rating system, but also to the fact that the _coefficients

of the multiple-rating system have been determined by _{a least-squares}

fit to the VPP predictions.

In some cases the improvement resulting

from the multiple-rating _{system is}

niinor, notably for the average

round-the-buoys conditions of Figure _{14 and, to a lesser extent, for}

beating and reaching.

The single-rating system is most deficient in

a downwind race as shown in Figure 13, and it follows that in

this condition the improvement resulting from a multiple-rating _scheme

is more dramatic.

Further work on this more _{flexible approach to handicap systems}

is planned, with emphasis on the introduction of displacement _{as a}

third independent parameter, the importance of which is _particularly

6. _{Other Computer Applications}

In earlier Sections work has been described in _{which digital}

computers were utilised to

analyse boat performance from the

hydro-dynamic and aerodyrLamic

standpoint, and to analyse race statistics

under a variety of

time-allowance systems. The _{potential uses of}

computers in handicap developments _{and administration}

are Virtually

limitless, and in this _{Section we shall describe}

two other applications

of the computer which _{offer great promise.}

In the past decade it _{has become routine}

to process rating-rule

measurements and certificates with _{a computer.}

The resulting bank

of measurement data _{can be statistically analysed,}

and a study of

this nature has been

carried out for the 3996 boats which held valid

IOR certificates in. North America in January 1974. _{The results of}

this study, which _{are described in detail in}

Ref. 7, are suarized

in Fig. 15. _{This Figure shows the variation of three}

non-dimensional

ratios, the sail_area/length,

draft/beam, and length/beam. _Rating

intervals of three feet _{have been chosén.}

Within each interval _the

total variation of each _{parameter is indicated by the}

vertical lines,

the mean value is denoted _{by the circles, and the standard deviation}

by the short horizontal _bars.

The population of _{each sample interval}

is indicated below Fig. 15. _{Variations of these}

statistics for

the larger boats, in _{the rating intervals between}

51 and 75 feet,

These types of statistics _{can be studied to detect design trends,} and are useful in suggesting the range of variation of a given parameter

over which a prospective rating rule must be applicable. _{In a related}

context, these statistics are being used _{to choose the systematic}

variations of hull forms for towing-tank _{tests as described in Section 3.}

Finally, and perhaps of the most immediate importance, these statistics

can be used as indicatörs of faulty certificates, _{since wide departures}

from the mean are not always due _{to vaTiations of design!}

As a final and especially fruitful _{appLication of the computer,}

Figure 16 shows a lines plan which has been fàired and drawn by

computer from a table of offsets. This programme _{offers a number of}

capabilities for handicapping purposes. _{It is possible to measure}

hull offsets at arbitrary but representative points, from actual

boat hulls, using the computer to draw a fair set of lines and store

a complete description of the hull for _{subsequent application of rating}

rules. _{Once this is done it is no longer necessary to remeasure the}

hull when the rule changes, and hull measurement can be done directly,

rather than by an indirect process involving _{the determination of}

stations with prescribed girths _{as in the IOR measurement process.}

If this approach is used as a basis for hull measurements, the

depen-dence of the rating on local or 'point' measurements should be

sub-stantially eliminated, hence reducing the _{potential for 'beating'}

the rating rule by means of local bumps, _{hollows, or chines. Moreover,}

with a given set of lines, and the f1otaion plane of the hull, one can readily determine the important parameters affecting the performance

of the hull, such _{as displacement, stability,}

wetted-surfaóe area,

prismatic coefficient, and _{the longitudinal position}

of center of bouyancy.

This computer-generatj lines _{capability is being used}

to

generate the lines pl4ns of the

systematic-series models for the

telf t towing testS, referred to above,

_{an4 will}

_{be ised in the}

future to test proposed

measurement schemes and rating-rule

modifi-cations. _{It also can be used}

to test existing rating rules _for

special purposes, as illustrated _{in Figure 17.}

Here, iso-rating

lines are shown,. along

which ballast can be moved without affecting the rating, and the change of rating due to movement of weights

can be _{readily ascertained.}

The results shown here have been obtained by utilising the lines-drawing

prograimne, in conjunction with different

trimmed waterplanes and the corresponding stability coefficients

(i.e., righting _{moments in heel) from which IOR ratings have been}

computed in each configuration.

The same Information could be obtained

by measuring _{boats in the field, in various states of trim, but at}

a prohibitively great effort and with questionable accuracy, since

small differences are sought between two nearly equal _{ratings, and}

7. _{Philosophical Problems}

Not all handicapping problems _{can be classified as technical,}

and the existence of philosophical problems must be recognized. _The

ultimate objectives of handicapping have never been _{agreed upon in}

any well-defined manner by the large number of yachtsmen _involved,

nor even by the rule-makers _themselves.

Indeed this fact is often

put forth as a reason, _{or excuse, for resisting change.}

This paper

will not attempt to address _{these problems for numerous reasons,}

not least of which is the fact that the author _{is only one of the}

approximately 10k owners or _{participants involved in}

ocean racing

under the IOR rule, o _{the even larger}

group of yachtsmen racing

under other handicapping _{systems and cruising in boats whose}

design

is influenced by the rules. _{But two of the more important}

prob-lems will be briefly

noted, with the hope' that the affected _participants

will discuss these questions more actively, and _{that future rule-makers}

will possess a more coherent

set of objectives than has _{been true in}

the past.

Two of the more fundamental questions of philosophy _{can be stated}

as follows: _{Firstly, do we desire}

a 'true-handicap' system under which

all the speed

parameters of a boat are accounted _{for, leaving}

the race results to depend only upon the skill and luck _{of the crew,}

or alternatively, an arbitrary

but well-prescribed 'rating-rule' which

sets forth rigid rules of the game to challenge the imagination _and

the handicap system be _{'pre-deternaned',}

as in most existing races,

or, in order that the variations _{of weather and other}

race conditions

be accounted for, should _{the system depend on post-race results,}

measurements, or judgements?

Both _{questions admit compromise}

solutions..

Espe-cially on the conflict between 'true-handicap' _{and 'rating-rule'}

objectives, history has shown that something midway between _{is most}

likely to be desired. _{The true-handicap}

objective is technologically

impossible to attain and, if sought, would encourage _undesirable

features of design (i.e., _{slow yachts!).}

Nor is the rigid

rating-rule objective universally popular, since this _{discriminates against}

a large number of existing boats,

forces owners and designers in

directions they regard as undesirable _{and ultimately motivates}

designers to 'beat the rule' _{at the expense of other}

objectives. _{Thus it seems likely that}

a broad consénsus would favour

a compromise where true handicapping is sought _{to the maximum extent}

possible, but stopping short of the pdint where _{boats are}

deliber-ately designed to be slow, _{or where existing 'rule-beaters'}

are

penalized out of proportion _{to their actual speed-potential.}

Much debate has ensued in recent years on the question _of

post-vs. pre-deterinined handicapping. Those _{who favour}

post-determinations

note that only by this _{means can wide variations in boat}

size or type

be accounted for properly, _{over a broad range of race}

conditions. Opponents

are unknown, the frustration of

post-race delays until the results

are announced, and mistrust for _{the judgements of}

a race committee

which must provide inputs _{such as average wind strength}

and direction,

wave and current conditions, _etc.

. Judging from

conversations with

knowledgeable participants, _{a consensus appears to}

favour

a pre-deterjnjned system, wherethe handicaps are well-stated

in advance of the race, but where thesé may possibly _{be varied from}

one race to another to suit the _{expected conditions.}

Where conditions can be anticipated in advance by the _{race committees,}

the rule-makers should provide a rational choice between _different

systems so that the best choice _{can be made for each race.}

Finally,

it should be noted that partial account of actual _{race Conditions can}

be made within a

pre-determjned system simply by making optimum use of the pieces of information

which are, separate and totally objective,

the distance of the race and the elapsed time of each _{boat; in this}

respect 'time-and..djstance' formulae _{combIne some of the}

advantages

of pre- and post-determined

systems and offer maximum potential for

8. Conclusions

In spite of the vast growth of ocean racing in the past two

decades, handicap systems have received very few inputs _{from the}

research and development _{activities in relevant fields of}

ship

hydro-dynamics, aerohydro-dynamics, and computer technology which also have

developed rapidly in this same period. _{In the preceding sections}

of

this paper several technical problems have been isolated _{and discussed,}

and methods of solution outlined. _{Some progress has been made}

already

under the recently launched NAYRU/MIT Ocean Race Bandicapping Project,

but the results obtained

thus far must be regarded as preliminary and utilised with caution.

There is an obvious need to gather more inputs

for sail and hull forces, and _{to. extend the applicability of the}

velocity prediction programme to a variety of hull forms and _rigs.

This programme can then be _{used to test existing and proposed}

handicap systems, and to develop handicap _{systems based more rationally}

on the speed-potential, of each boat.

Measurement techniques and instrumentation must be developed to facilitate the determination of hull offsets both accurately and economically, for use in conjunction with the computer lines-fairing

programme. _{In the short term this will aid}

the administration of

existing rating rules, and in _{the long run it is}

a necessity if we

are to obtain handicap systems which _{account more completely for}

such obvious and important

parameters as displacement and vetted _surface

area.

with emphasis on those

parsmeters, such as the heel inclining _moment,

where present methods are known to be unreliable. _{Finally, these}

methods and approaches must be tested against existing

and hypothetical boat design, and against

existing race data, and appropriate empirical

corrections sought in the areas where deficiencies _occur.

Empirical

corrections are inevitable, _{but by proceeding in}

this manner it is

hoped that their importance will be secondary rather _{than primary,}

and that the resulting

handicap system will be more stable, and less

susceptible to changes forced _{by the discovery of}

'loop-holes'. If

this goal can indeed _{be attained it promises}

more equitable and economical

ocean racing for the yachting _public.

ACKNOWLEDGENT

The results presented herein are based _{upon research carried}

out under the Ocean Race _{Handicap Project,}

administered by the North

American Yacht Racing Union and supported by _{generous donations thereto.}

The author also wishes to note that preliminary _{work was performed}

during visits to the Universities of New South Wales _{and Adelaide,}

with support from the

Australian-American Education _{Foundation and}

Newman, J. N.:

'A Fundamental Approach to Ocean-Racing Handicap

Rules,' HISWA Symposium, Amsterdam, 1973, _{p. 187.}

Newman, J. N.: 'Handicapping

of Ocean Racing Yachts,' _unpublished

paper presented to the 28th November _{1973 meeting of the}

Aus-tralian Branch, RINA, Sydney.

Kerwin, J. E., Oppenheim, _{B. W. and Nays, J. H.: 'A}

Procedure

for Sailing

Performance Analysis eased on Full Scale Log Entries

and Towing Tank Data,' _{M.I.T. Dept. of Ocean Engineering}

Report

No. 74-17, December, 1974. Kerwin, Justin E.: 'Sailing

Performance Predictions, Part I

-General Theory _{and.Applications to BAY BEA Family,'}

M.I.T. Dept.

of Ocean Engineering _{Report No. 75-1, February, 1975.}

Newman, J. N. and Hazen, G. _S.:

'Race Statistics and Time Allowance

Comparisons,' M.I.T. Dept. of Ocean Engineering Report No. 75-2, February, _1975.

Oppenheim, Bohdan W.: 'Documentation _{of Programs for Analysis}

of

the NAYRU IOR Yacht Rating Tape,' M.I.T. Dept. of _{Ocean Engineering}

Table I

Time allowance formulae (R

= rating in feet, k = arbitrary

constant related to

scratch boat rating)

Formula NAYRU TOD RORC TOD 1.0 0.6(k - R_14'2) 1.43 1.0 k -R1'2

+2.6

0.6 + (C/D - k)Rh/2 1.43 + (CID.- k)(Rh/2 + 2.6) PFS CYCA2 TOT k l-A

23

1.5 - 2.75Rh/2 k(Rh16 - 0.96) k-1.5 [1.5 C/D + 275]Rh/2 k(Rh/6 CYCA TOT k[(R-8)'I - 0.75] 0 k[(R_8)1/2 RORC TOT k(R1'2 + 2.6) 0 k(R1/2 RORC2 TOT k(.1999Rh/2 + 34) 0 k(.1999Rh/2 k Rh/2 NAYRU TOT O i + O.057R/ (1 + O.O57RhI2)(C/D)

Figur e

of

Merit

TABLE II

Figures of merit for 1973 Fastnet Race

NAYRU RORC RORC CYCA2 CYCA RORC RORC2 TOD TOD PFS TOT TOT TOT TOT i

C.Oi8

0.0158

0.0306

0.0046

0.0032

0.0077

0.0018

2

0,0228

O.Cl9Li

0.0300

0.Ó129 0.0112 0.0158

0.0115

3

C.013

0.0166

0.0235

0.0141

0.0106 0.0151

0.0126

4 C.0301 0.0255 0.04011

0.0169

0.0151 0.0194

0.0132

TAt3LE

1.11

SUMMARY OF FIL'URES OF MIT

19(3

_{SEINE 8AY RACE}

O 024

0.0243 0.0361

0.0184

0.015g

0.0225

0.0165

t1ApW ICH-tIOOK 0.0313

0.0279

0.0424

0.01(5

0.0147

0.0217

0.0164

LE PIAVRE - ROYAL 0.0200 0.0161

0.0295

0.0069

0.0039

0.0116

0.0051

MORGAN CUP

0.0214

0.0178

0.0310 0.0081

0.0059

0.0122

0.0060

CO Wr. S-O INh RD 0.0279

0.0219

0.0300

0.02,3

0.0244

0.0328

0.0246

CHANNEL RACE

-0.0157 -0.0221-0.0196

-0.008f -0.0110 -0.0042

-0.0116 -0.0115

FASTNET RACE

0.0229 0.0194 0.0301

0.0130

0.0112

0.0158

0.011b

HONOLULU RACE

-0.0036 -0.0119 -0.0023

-0.0043 -0.0018 -0.0067

-0.0118 -0.0070

SYDNEY-HO8AR T 0.0174

0.0129

0.0117

0.0193

0.0189

0.0216

0.0166

1974 A N CL O T E -0.001-7 -0.0051

0.0042 -0.0138 -0.0131

-0.0130 -0.0179 -0.0161

FT. LAUDERDALE

0.0040 -0.0008

0. 0087 -0.0029 -0. 0021

-0.0027 -0.0071 -0.0050

OCEAN TRIANGLE

0. 0130

0.0056

0. 0 166

0.0082

0.0096

0.0081

0.0037

LIPr0N cu

-u.0311 -0.0319 -0.0255

-0.0 389 -0. 0381 -0.0377

-0.0437 -0.0416

MIAMI-NASSAU

-0.0143 -0.028 -0. 0204

-U .0026 -0. 0016 -0.0023

-0.0087 -0.0054

NASSAU CUP

-O.000

-0.0055

O 0044 -0.010f -0.0095

-0.0102 -0.0160 -0.0133

ENM(JDA RACE 0.0189

0.0113

0.0203

0.01 If 0.020 o

0.0163

0.0144

CHICAGO-MACK INAC 0.0029

-0

O () It)

0.0066 -0 0040 -0.0051

-0.0004 -0.0068 -0.0064

LE HAVRE - ROYAL

0.0579

0.0549

0.0 (16

0.0405

0.0381

0.0449

0.0387

fr1R(jAN CUP

0. 0208

0.0145 0. 0197 0.0241

0.0185

0.0337

0.0228

CO w Es! L) I N A N D -0 0061' -0.0096

0.0043 -0 0208

-0.026k

-0.0134 -0.0208 -0.0228

CHANNLL RACE 0.0657 0.0615

0.0152

0.0532

0,0503

0.08?

0.0510

4EAN 0t MAGNI TUDE

8PITISÑ RACES

0.0290

0.0254

0.0354

0.021f 0.020n 0. 0246

0.0205

US ACLS 0.0100 0.0118 0.0121 0.011'

0.0113

0.0108

0.0145

ALL RACES

0.0203

0.0195

0.0246

0.01(2

0.016?

0.0186

0.0177

AY R U

RORC

NORC

CYCA

CYCA

RORC

RORC2

Ev L N T IOD T ori PFS TOT TOT TOT TOT

Y A Beat _0.47 0.86 _0.48 Reach _{0.87 0.59} 0.88 Run _0.28 0. 3]. _0.13 Average _{0.39 0.59} 0.42

(FEEDBACK)

\\

DATA BANK HANDICAP SYSTEM RATING RULE AND TIME ALLOWANCE RACE COMMITTEES AND USERS EXISTING VALIDATE _{vPP a} DATA _VPP PERE TEST PROG.

PERFORMANCE PREDICTION SYSTEM BOAT LINES AND GEOMETRY

t

MEASURING TOOLS AND LINES FAIRING

Fig. 1.

Flow chart of NAYRU/MIT Ocean

Race }Iandicp

Project.

U)

o

C

a

12

9

3

o

L:20

0

l40'6

10

Sail Area Ratio, S/S0

Fig. 2.

Speed made good

to windwardbased

on velocity prediction

program (VPP) for different

waterline

lengths

L .

Six curves are 8hown

corresponding to true wind

velocities of 5, 10, 15, 20, and 30 knots.

O6

10

1406

1406

10

L:30

L45

L:60

2

₉

3

o

06

L20

10

1406

L=30

10

1406

L45

10

Sail Area Ratio,

S/S0

Fig. 3.

Predicted speed from VPP

for a reach in true wind velocities of 5, 10, 15, 20, 25, and 30 knots.

I4 06

L:60

I0

U)

o

C

t.

2

9

L:20

L3O

l0

L45

L=60

10

F406

l'O

1406

10

1406

Soil Area Ratio, S/S0

Fig. 4.

Predicted speed from VPP for

a run in true wind

u) _4-

o

C

a _4-

_D

_o

9

₃

l0

I406

0

l4O6

10

Sail Area Ratio, S/S0

Fig 5.

Predicted average speed

from VPP for hypothetical

round-the-buoys race in

true

wind velocities of 5, 10, 15, 20, 25, and 0 kw,

14 06

L:60

10

La20

L:30

L45

NA'! Cl'

I-OIT

S AGI RECLUTA Tu CHAP ISlA SALTY

CSE

SA FARI 50 PC F l'Y AUlA PPCSPFCT OP WHIT UATLO LIT SA

A DE

APOLLO _WA-WA-TOCIlT CAP ILLION PEN CUICK VI CATTNA LIT STIJAPT LITTLE PUrIN RAITLECRY ANTIGUA V C HA ST! NEI GIN PC GO WHIP! WINC Ti! JAK/P ANL'A SPI'TT 0F D.ELFT HTT.VNF -LT APOLtO LI RA GA0

nl

C A roi. I N A t!IVA TI JAN

0T

FTRFP3PANC ITT ADVFNTR E hAP PAPY KTSS III 0TT?P

-SAYUT.A T! INSCHALLAH S!ltFISTA F !!J!P 100 ?IATC!'IA!C ER PC Y P

)9 A

NO!YF.t1A

IX

ITITC:h-TRATSCH PO P.10 ' A WT1.C.T?SP XII VEAI..0

Il

Ç1ANT0M II WIN0'TJH II N A Y U I1ATING E CSPUC 41 9 37.0 44

i

114.6 ¿i5 O 56.11 38.3 34.9 40.P 34. 1 _51.3 ¿42.0 33.0 61 9 13.2 4. 2 36.11 34.0 33.9 33.5 36.3 36. q 47L4 35.6

3 e

36.4 38_i 34. 2 33.0 39.4 110.9 40.2 36.8 C) IS. 2 L475 45.11 33.6 31.0 3. 'i . (40. 0 35.6 P 3. ¿. 1 6. 9 36.s 34.5 3 4 5

i

6 e 9 10 13 1Q 15 28 16 19 23 20 2? 21 25 26 33 27 25 30 34 21 35 39 414 '48 '12 17 52 111 123

ei

83 '10 1 oS P 111

11

i 29 1; l i ¿b 1411 CISIANCE CP CP TL5 605.00

'111ES. SCRATCH PAlING USED WAS

29.0 5.17 5.68 5.58 5_co 5.46 5. ¡41 5.46 5.28 5.30 _{iS. 19} 5.08 4.51 5.04 ¿1.17 S. CC (4 57 4.54 4.95 U. C4 4. SLI '1.52 '1.50 '4 .84 1. 18 (4.87 'I. F6 ¿1.84 ¿1.16 4.84 ¡1 77

U. 75 Li_73 4.75 '4. SR ¿1.72 4 76 4.54 I. 12 4.62 Li_61 ¿LS') 4.55 Li.'7 '1_54 i. 52 '4.52 4.54

FCC PF CSIEIt 2 5.56 1

i

5.63 2 3 5.48 'I 5

543

(4 6 5.36 5 8

S.ti

(4 5.41 7 7 5.35 8 9 5.2 q 1C 5.17 10 17 4.95 11 23 4.91 15 14 5.02 16 119 4.70

il

15 4.58 18 18 4.95 2) 24 .4.91 21 ig 11.51 22 2 4.52 2) 21 4.93 211 25 4.8'; 25 26 4.81 26 38 4.78 27 27 4.85 28 29 '4.83 9. 31 14.83 30 33 1.PC 31 8 4.83 34 32 4.P2 36 ¿14 11.72 37 52 i.7C . 33

0

4.f't: fl ¿16 4.72 '40 16 ¿4.56 14 54 (4_(5 42 62

417

1$ 1119 LL1J6 611 59 4.11 61 97 . 4.61 7..

iCi

¿1.10 76 1CR . 4.58 62 1112 4.1144 (47 124 4.52 90 117 'L 128

4. '2

94 135 LIU9 q-1)2 ¿45Q 914 127 4.52 100 10'C rrs CYc2 PP CSPFED PP CSPEED 5.75 5.73 5.16

c-Sc

S. Sb c_cs 5_53 5.43 5.38 5.24 C 23 5.C8 5. Oli s_Cl S.0 Li S.0 i 5.00 4_59 4_cs 4. 99, 4.58 (4 96 4_95 4.94 li_911 4_97 14.51 ¿1.88 4.17 11.86 4.83 4.83 5.04 '1.79 4.91 4.18 4.67 11.67 2 .3 r' 7 e 4 6 9

io

72 27 14 135 is- 18 23 19 21 20 26 31 77 34 54 53 62 37 39 92 ₁₀₅ 1111 85 17 87 132 203 1211 120 121 136 1 '93 17" 150 175 i JI R 1.114

i

(J Fi CYCA PP CSPFED 5.56 5.61 5.46 5. 38 5.33 5.23 5_37 5.11 5.17 5.12 ¿1.87 4.82 U 98 4.59 4.94 4.139 4.811 _4.88 4.87 4.08 11.82 4.79 4.66 4.18 ¿4.76 4.76 4.72 (4.71 (477 4 6.3 4_59 '4.57 4.614 -4.') J 41.61 4.55 4. U 4.5(8 _4.55 ¿4. 5(4 4.52 4. 3' ¿1.Ll4 LI. ¡49 Li_43 4.40 4.111 4.114 2 3 s 7 q 4 6 e 10 24 25 1(4 146

is

18 22 19 21 20 23 26 64 28 37 36 1111 10 32 82 93 Qq 71

il

811 123 19'; 112 10H 115 120 1813 155 139 159 171 170 152 RO RÇ PP CSP'EP .5. 55 s. r. i C45 5.31 . .33 5. 15

539

5. 34 5.18 5. 14 ¿4.83 11.99 (8. 48 4.95 ¿4.91 4.90 11. 89 _4.89 4. (III 1.81 _{4. 68 '4.80 4.77 4.78 (4.73 '8.79} ¿4 79 4.611 4.1") 4.59 '1.66 (4.92 _4.63 ¿4. 5 4 4.12 4.56 4.5_7 4.54 4. 37 4. 4, 4.51 t4 4.42 '4.42 4 46 2

i

3 6 7 ₁₃ 4 5 9 10 _{Sq (49} 1(1 19) 15 18 23 20 21 19 28 '43 914 _¿li 5(4 57 67 4.? 38 101 126 132 95 17 _{'100 161} 7113 121 120 131 139 i PR 175 151 178 1h38 ₁₈₉ '73 R08C2 NAYRU TOT PP CSPE"D PP CSPEEG 5.44

557

5_37 5.28 5.21 5.02 5. 3" 5.11

s. ii

¿1.7" 4_7c .4.97 ¿4

4.9'

4. 8fl 4. 131 4.86 4.87 4.7.9 41.76 (4.61 4.76 4.71 4.7.3 4.68 4.71. ¿1.77 _ Sq 4.5(4 ¿1.51 4.61 4.87 4. 3') 4143 4.24 4 51 4.55 (4.51 U_Si 4.32 4.187 4.48 4.'11 4. 37 4_39 4.141 2

i

3 s 11 4 6 R io 34 (11 14 16.3 15 iO 25 19 21 20 28 47 87 '19 59 51) 67 52 50 100 117 127 93 17 _'102 151 210 130 122 115 143 196 176 153 17'; i 90) ₁₈₈ 174 co

5.58 5.40 5. 32 5. 71 5. 11 5.3(4 S. 30 5.118

5. ii

4.79 4. 78 4.97 4.45 '4.91 ¿4.89 1. 82 4.87 (1. 86 4.87 4_HO- 4.77 4.64 4.77 lId -71e 4. 711 4.-69 (I. 77 ¿4.77 4.60 4.56 (4.54 4.62 4.89 4.59 4.49 tI. 27 '4.54 4.55 4. 53 '4.51 '1.13 4.43 4.413 4.'42 L4_ 33 _4.39 4.43

Fig. 6

Listing of 1973

Fastnet Race performance

under eight time

allowance systems for

part of Class I.

5.518 2 5.61 5.145 J 5. 36 ¿1 5_Ji 6 S

ill

H 5. 3f, 5 S. 12 7 5.17 9 5.13 10 4.84 22 4.81 37 l4 98 14 4.52

t'o

4914 '1.90 18 - 4.84 30 4.88 20 4.81 24 ¿4 8H 21 11.82 39 11.79 ¿lb ¿4.67 72 U. 713 50 60 4.76 69 4.72 611 4.78 64 4.713 55 4.62 96' 41.5') 107 '4.51 11H 4.64 94 4. 90 17 4.61 102 4.53 127 4.11. 1913 4.55

ils

4.56 1213 4.511 138 4.52 144 4.36 195 177 ¿4 (1 '4 157

l44)

181 ¿1. (iO i f4') 4.41 1.6 4.45 116

6-* + + ++ i:

+-$+

+ + +

lf

+ Li_1

4 -4**+++

+

>

+4

+ +-I.

3-2--

I

± -

--20

30

4Q

50

₆₀

₇₀

RATING (FEET)

+ +

Fig. 7. _{Actual speed of all boats in 1973 Fastnet}

Race. + + + + + + + + + + + + + + + + C/.)

H

o

z

5.L

>-

I-o

o

-J