Northern Ireland sailors Ryan Seaton and Matt McGovern have qualified Ireland for the 2012 Olympics in the 49er class.
It will be the first time since Athens 2004 that Ireland have been represented in the 49er event.
Seaton and McGovern guaranteed their place in London as the moved into 10th place in the class at the World Championships in Perth on Wednesday.
Racing continues to Sunday but the Irish duo are certain of a top-14 spot.
The 67 boat fleet now splits into Gold and Silver fleets with the top 25 boats entering the Gold fleet.
With only 14 nations in the Gold fleet it is now impossible for Seaton and McGovern to fall outside the top 14 nations thus securing Ireland's place on the start line in London.
Seaton and McGovern had their best day so far on the water on Wednesday, placing fifth in both races.
Racing will continue through to Saturday with the top 10 teams then continuing on to the medal race on Sunday.
"It's a brilliant result for the guys, to be in sixth nation position and to have secure Olympic qualification at this stage is something special," said ISA Performance Director James O'Callaghan.
In the Star class, Peter O'Leary and David Burrows had a 16th and a 24th on Wednesday from the fleet of 41.
They slip one place to 15th overall and continue their fight to secure Olympic qualification with only one day of racing left before the medal race on Saturday.
The Star class have a rest day on Thursday with their final day of fleet racing taking place on Friday.
The top 11 nations will qualify for the Olympics and the Irish pair have maintained their position as the 11th nation.
James Espey in the Laser also had his best day on the water with a 3rd and a 20th and now lies 63rd overall.