Coastguard Wanaka Lakes president Jim Talboys said the volunteer response to the simulated emergency scenario had been hugely successful.
About 30 people from Wanaka Lakes, Clyde and Mackenzie Lakes Coastguards, the Hawea Marine Group, police and LandSAR Wanaka took part in the exercise, which was written by Mr Talboys and Coastguard Southern Region operations manager Mark Whitehouse.
The make-believe scenario involved four people who had reportedly gone out on Saturday on a hunting and fishing trip on the lake.
They held a party that night where there was ''a lot of alcohol drunk'' and one member of the group attacked two others with an axe and produced a rifle, Mr Talboys said.
An emergency call to police at 8am yesterday revealed only that people were in urgent need of help on Lake Wanaka.
The marine search and rescue crews were deployed shortly after, while an incident management team was based at the Wanaka police station.
Mr Talboys was impressed by the speed with which the crews found the ''targets'' - a deceased person (dummy) floating in the water, who turned out to be the original assailant, and a vessel with a badly injured person on board.
The bloody boat scene was created using a large volume of tomato sauce and a barely conscious and unco-operative patient, played by a Coastguard Wanaka Lakes volunteer.
The two other members of the party had escaped into the bush and were also successfully located by the search team.
Apart from one of the private boats having a mechanical failure during the search and requiring a tow back to shore, everything had gone ''extremely well'', Mr Talboys said.
''I can say as the person who set it up, they probably found the first person two hours earlier than I thought they would.''
As well as providing an opportunity to simulate a multi-agency response to an emergency situation, the event identified gaps in training and procedures and areas that needed further development.
Mr Talboys said Coastguard volunteers carried out more than 250 hours of training each a year.
''It's a huge commitment for our volunteers and it only happens because of the generosity of their families for them to ... give up their time.''
