Team Race Formats - cont.
If the number of teams is not too large and if the event can be organised in several days, this format is the ideal one since all the teams have the chance to test their skills against each of their opponents. However, it involves a large number of races e.g. for 16 teams there should be 15x16/2=120 races if all the teams were to sail against each other once. The formula to calculate the number of races is R=Nx(N-1)/2 (N=number of teams, R=number of races)

Results after the second stage at the IODA European Team Race in Italy - August 2010
A variant of this system is to allocate the teams to two groups, which sail a 'split' round robin and then move to semifinals and finals.This cuts the number of races considerably: for 16 teams, there will be two groups of 8 and each round robin will consist of 7x8/2 = 28 races, adding up to 56 races in total. After this first 'stage' the four best teams of each group move to the semis and the finals. The rest of the teams can sail a parallel 'Silver' cup.
As said above, time is an issue to be aware of when considering this format. For a two-day event a 'perfect' round robin would be suggested only for 10 or fewer teams. For 10 teams the number of races for a perfect round robin is 45. If there are 12 teams the round robin could be organised for two groups of 6 (number of races = 30) of which the first two teams would go to semifinals. But even this solution can prove impractical for two days of races if sailing conditions are not favourable.
This is a much faster format as the number of teams decreases from one flight to the next and there are fewer races in total (e.g. 32 races for 16 teams). In the end, there are only two teams arriving at the finals, one of them having lost not a single race and the other only one.
As a general basis, the elimination format is ideal for a regatta where team racing is complimentary to an event of individual races. Competitors are already at the venue and teams eliminated early still have the individual races to sail. However, for an event organised exclusively for team racing, the elimination format is not recommended since travelling to the venue to sail only two races can be frustrating.
Seeding is the way to sort the teams and position them in the grid, or in each group when organising 'split' round robins.
In the case of the double elimination format, the grids are prepared so that the best team (team 1) sail against the worst team (team 16 in the case of the grid for 16), the second best (team 2) sail against the second worst (team 15), etc. If teams are not sorted based on a ranking there is a possibility that two good teams sail against each other in the first flight, thus the risk exists that one of the best teams is eliminated at an early stage. In the IODA Continental and World Championships, teams are ranked based on the first individual races of the championship. For an club event, a national ranking of individual races or a previous championship can serve as the basis for the seeding.
For a complete round robin this issue is of no importance as every team sail against every other team. For a split round robin a ranking is helpful to distribute teams evenly in each group. However, this is not such a vital issue here and if a ranking is not available teams can be separated randomly.

The IODA standard grids are for 16 and 48 teams.
In the case of 48 teams, the system consists on a 'qualification stage' after which the first 16 teams are selected. These 16 teams then participate in a second stage with the usual 16 team grid. In the qualification stage, the teams that lose their second race in flight D go to a 'pool'. Of these, the team with the lowest points qualify for the final stage as team 16th.
How to use the grids for a number of teams other than 16 or 48
To 'convert' grids we use the grid with more teams than the teams entered at a particular event and 'give a bye' to teams that do not exist. For example to convert a grid of 16 to a grid of 13 we 'give a by' (leave a blank) to teams 14, 15 and 16 and renumber the races accordingly. Teams 1, 2 and 3 will not sail races in flight A.

Follow the link to download an example for 22 teams. The xls file contains four sheets:
In this event there will be two stages:
Qualification stage: use grid FINAL FOR 22
Final stage: use grid STANDARD 16
*In the case of 32 races, teams that lose for the first time have the chance to fight for a place in the final. In the case of 30 races a team that lose for the first time cannot have a place in the final and can only fight for a third place at the best.
The IODA use the elimination series at all of its events except at the European Team Racing. The reasons are mainly what has been explained above: time and number of teams.
Worlds: The objective is to give an opportunity to as many teams as possible to participate in the team racing. The 48 team grid is used. The races are scheduled to be sailed on two days, with a third spare day in case weather conditions do not allow for the completion on two days.
Continentals except the Europeans: the grid for 16 teams with 32 races is used. The series is sailed on one day with a second day as spare.
European Team Racing: the event is run in five days, for 16 teams. The round robin format is used, with a 'split' round robin for 8 teams each, followed by semis and finals.