Brosnahan (51), a Dunedin conference manager, is a versatile competitor who has also won national veterans titles in athletics and cycling.
She spearheaded a strong Port-United women's team that won seven gold medals, eight silver and two bronze medals at the two-day championships at Lake Ruataniwha.
At Lake Karapiro last year, the Port Chalmers rowers won two silver and two bronze medals.
Brosnahan won her gold medal in the women's aged 50 to 54 coxless four with Robyn Cameron, Wibke Schultze and Imogen Coxhead in a time of 3min 52.68sec for 1000m.
She also won a silver medal in the quadruple sculls with the same crew in 3min 50.08sec and linked with Don Strachan (Mercer) to finish second in the mixed double sculls.
Her third silver medal came in the mixed quadruple sculls when she linked with Coxhead and Mercer scullers Neil Pollock and Strachan.
Coxhead (50), a senior lecturer in business and commerce at the Otago Polytechnic, was the most successful Otago competitor at the championships and won five gold and two silver medals.
Her gold medals were in the women's aged 50 to 54 single sculls (4min 19.67sec), the women's double sculls with Cameron (3min 57.87sec), the mixed four with Cameron and Awarua rowers Steve Geary and Kevin Flutey (3min 34.66sec), the mixed quadruple sculls with the same crew (3min 35.44sec) and the women's four.
Cameron, an IT specialist at the Dunedin Hospital, won three gold and two silver medals.
Schultze won a gold and two silver medals and veteran Faye Forgie (65) won two gold, two silver and a bronze medal in the 65 to 69 age group.
Her gold medals came in the single sculls (5min 16.30sec) and women's double sculls with Jocelyn Dobson (Riverton) in 4min 42sec.
Other Otago rowers to win gold medals were: Tom Gardner (Twizel) in the age 45 to 49 singles sculls (3min 50.86sec) and mixed double sculls (3min 52.35sec), Rebecca Craies (Otago University) women's aged 40 to 44 singles sculls (4min 25.52sec) and Bert Kemp (Dunstan Arm) and Anthony Ellman-Brown (North End) in the men's composite age group eight (3min 37.22sec).
Ellman-Brown also won a silver medal in the men's aged 65 to 69 single sculls (4min 20.69sec).
The Oamaru mixed four of Hayley Ambler, Kevin Kearney, Doug Pile and Angela Drew won a silver medal (4min 13.75sec) in the 37 to 44 age group.
John Parnell (Otago) won a bronze medal in the men's over-70 double sculls.
