New South Wales police have revealed more details into the deaths of two sailors,in the Sydney to Hobart yacht race

A 55-year-old Western Australian man on Flying Fish Arctos, and a 65-year-old South Australian man on Bowline, were killed after being struck by sail booms, about two hours apart.

The man who was rescued after falling overboard the Poco Russo , has been named as 37-year-old Luke Watkins.

Superintendent Joe McNulty, says they believe the boats may have been changing sails and not sailing with the wind.

He says it's a technical change of sail at sea, and with multiple moving parts, that may have been a contributing factor.