French HN system with light wind correction and rating files

There are two French handica systems, not totally compatible. Only one is displayed in the Ranking Systems/Rating systems.

The VL (voile legere = dinghies) and the QS (quillards de sport) systems may be accessed through TCF or TCC options even if the coeff is known as TMF (time multiplying factor). Sadly, Sailwave shows a tip c=e/r where r is a dividing factor. Should be c=e*r. FFVoile publishes also the tables as PN, times in seconds/mile, and the RYA Portsmouth may be used.

For Cruisers, the French Handicap National (HN) uses a TMF system, based on Groups (speed difference 45 to 60 seconds/hour) and Half Groups:

  • for Groups 0.0 to 11.0, the SM (seconds/mile = PN) is defined as 973-15*Group
  • for Groups 11.5 to 30.0, SM = 808-10*(Group-11)
  • for Groups 30.5 to 45.0, SM = 618-8*(Group-30)
  • for Groups above 45.0 (no boat in these groups), SM = 498-6*(Group-45)
    and the easiest way to tell it to a computer is the formula:

MAX(973-15Group,808-10(Group-11),618-8*(Group-30), 498-6*(Group-45))

The handicap of a boat may be personalised by bonifications and penalties in groups or half groups.

From SM, TMF is calculated as 600/SM, rounded to 4 decimals

But as for all single number systems handicaps don’t show performance in light weather.

A second number SM (=PN) is given under a form of seconds per mile. The allowance in ToD is related to a reference boat sailing 683 sec/mile, the relationship is ToD = SM-683 or .5*round(1200/TMF;0)-683. So only one number, SM or TMF needs to be taken in a rating file.

So a third number is given, CVL “coefficient de vent leger” - light wind coefficient. The coefficient is low for light boats with large sail area, and this coefficient gives a bonus to heavy boats in light weather.

The system is included in the French FReg software but not applicable with Sailwave.

The formula is as follows:

  • Calculate SM from TMF SM=.5*round(1200/TCF,0)
    of calculate TMF from SM TMF=round(600/SM,4)
  • Calculate average speed V=D/ET
  • Calculate bonus on ET as B=CVL*(2-SM*V/1800) and B is no less than 0
  • CT = ET*(1-B/100)*TCF

Can be condensed in a single formula [Note ET in decimal hours HH+(MM+SS/60)/60 ]


Depending whether you are starting from TMF or from SM, the formula becomes:

  • CT=ETTMF(1-max(0,CVL*(2-round(1200/TMF,0)*D/ET/3600))/100)
  • CT=ETround(600/SM,4)(1-max(0,CVL*(2-SM*D/ET/1800))/100)
    This cannot be used at present time with Sailwave. It is also not urgent, as the French software calculates it properly. But as several Belgian clubs are using Sailwave for dinghy and keelboat racing, and they are restricted to the basic use of HN coefficients (just TMF or SM=PN) for cruisers, a development of this system is welcome.

For rating files, the structure should be “hn,boat,TMF,CVL”

and one or two boat field(s) should allow to enter bonifications and penalties.

A rating file for personalised boats records should be “hn,boat_id,TMF,CVL,BONIF,PENAL”

Philippe DE TROY