Ireland's Olympic sailors were left reeling after the 49er class crew of Sean Waddilove and Robert Dickson were demoted from seventh to 13th in their bid to make the crucial medal race.
The Dubliners had progressed into seventh place after six fleet races and were nicely positioned.
However after Thursday's races, their fifth and sixth this week, it was ruled by the sport's technical committee that the trapeze harness used by the helm of Ireland weighted 2.09kg and thus over the 2kg limit.
The crew appealed the ruling but it has now been learned that was unsuccessful.
Waddilove and Dickson had finished in sixth and seventh position in Thursday's races but the ruling meant they were moved to last place in both.
That saw their overall position drop out of the top 10, but they remain in contention for the medal race.
Earlier, Waddilove had said: "We’re feeling pretty good.
“We had a pretty average day yesterday, but we learned from our mistakes and we were really nicely set up today so that made our life a lot easier.
"At the halfway point, we’re still ready to go. One race at a time – and still keep picking off the places.
“We had quite steady conditions, maybe medium winds and not too wavy.
"First race was just about going fast and keeping yourself clear of other boats, not making too many mistakes and that was really it – just keep it simple around the racecourse.
"Really nice conditions here – I don’t think you can get much better.”
Dickson added: “I think what we’ve been doing up to now has been working, so we’re going to keep everything the same as we always sail, keep going and tick off the places, as Sean said.”
