Wild Oats XI has retained its Sydney to Hobart line honours standing after a post-race protest against it was deemed invalid.

Key points: On Friday Wild Oats XI crossed the finish line ahead of fellow super maxi Black Jack

On Friday Wild Oats XI crossed the finish line ahead of fellow super maxi Black Jack Black Jack's skipper Peter Harburg complained Wild Oats XI's tracker was not always on which disadvantaged others

Black Jack's skipper Peter Harburg complained Wild Oats XI's tracker was not always on which disadvantaged others A protest launched on the basis of Harburg's complaint was deemed invalid

The owner/skipper of runner-up Black Jack Peter Harburg claimed Wild Oats XI's automatic identification system (AIS) was not transmitting throughout the whole race and that it disadvantaged the crews of Black Jack and third placed Comanche.

The Sydney to Hobart race committee subsequently lodged a protest against Wild Oats XI.

But a five-member international jury ruled the protest was invalid because it needed to have been lodged by a competitor.

Russell Green, the chairman of the international jury, said the race committee's investigation and protest had arisen from a competitor in the race, and therefore a person with a conflict of interest within the meaning of the racing rules of sailing.

"For the protest to be valid under racing rules of sailing, a competitor with the information about a potential rule breach must lodge a protest," Mr Green said.

"The sport of sailing is a self-policing sport. These guys are out there, out of sight, out of land, we don't have referees.

"If there's a possible breach, then it's up to the competitors to bring a protest."

Wild Oats XI on River Derwent 2018 ( ABC News: David Hudspeth )

'Common sense has prevailed'

Wild Oats XI skipper Mark Richards said he was very happy with the decision.

"I think common sense has prevailed," Richards said.

"This is a family and team of integrity and we go to the utmost lengths to do everything by the rules, sail by the rules and we go to the extra effort in many areas."

"It's just a shame that this came about, but it's one of those things — everyone has their view, and we totally respect the decision."

Mr Richards said any protest was unfortunate but it was part of the sport, and other sports.

"We'd just like to move on and go and celebrate the win."

The crew of Wild Oats XI celebrated a stunning win on Friday, crossing the line in a time of 19 hours, 7 minutes and 21 seconds in one of the closest contests in the race's history.

'I believe them,' says rival skipper

Harburg reported Wild Oats XI's automatic identification system (AIS) was not transmitting throughout the race.

He claimed the lapse disadvantaged the crews aboard Black Jack and third-placed Comanche because they could not see where Wild Oats XI was at all times.

Black Jack skipper Peter Harburg said other super maxis were disadvantaged by Wild Oats XI's AIS not being on. ( ABC News: Monte Bovill )

While not technically a racing tool, the AIS was introduced as a mandatory requirement this year to improve safety, and race organisers said the requirement to have it on was communicated in race briefings.

Wild Oats XI skipper Mark Richards claimed the AIS system was flawed while the boat's engineer Cameron Baillie said he believed their AIS was on throughout the race.

"We were receiving the whole time, our device was telling us it was transmitting, so how else are you meant to know it's not transmitting, unless someone tells you?" Richards said.

Harburg said he was satisfied with the jury's decision.

"If Wild Oats XI said they had [their AIS] on then I believe them," he said.

Harburg said he had been disappointed his crew could not pick up Wild Oats XI's signal and so he had said something about it but he said he did not think he should have made a formal protest.

He maintained if a yacht did not have its AIS on, every other boat was disadvantaged.

"Because they can see us, but we can't see them," he said.

"Maybe they had it on, and it just wasn't ringing properly."

Harburg said he would continue to be good friends with Richards.