Despite conceding time and places on the water, she was still within six minutes of the three top veteran and open women who finished ahead of her.
“It was good to get that ticked off,” Rennie said.
“I’d never been in a boat (like this) until six months ago.”
Her time of 9 hours and 1 minute represented her longest period of continuous exercise, she said.
The former Olympic cyclist is training for next year’s Coast to Coast.
She said that despite not achieving the result she wanted in her first outing, crossing the finish line after battling through a tough crash was cause to celebrate.
Up front in the women’s race, it was one of the closer-run duels in Motu history.
Ali Wilson beat veteran Simone Maier by only 66 seconds after Maier trailed her for three-quarters of the race before catching her near the cycle-to-kayak transition.
Both were out on their own and cracked eight-hour race time while multiple long-time race champion Elina Ussher was a quarter-hour back in third and runner-up in the veteran category.
Wairoa-born Sam Manson continued his strong year in multisport, finishing second in the race he won three years ago.
Manson, who was chasing his second victory at Motu, was comfortably beaten by long-time rival Dougal Allan. Allan crushed the field from start to finish, leading every stage and finishing with a time of 6:58:48, well ahead of Manson’s 7:22:07 finish time.
Manson had to fight hard to stay clear of third-place finisher Bobby Dean, battling from behind in the second half of the event after a slow start to finish over six minutes clear of Dean.
Gisborne-based male athlete Tomas Kocar was also in the individual race, finishing 11th veteran and 40th male competitor overall with a time of 10:13.38.
Former Gisborne multisport athlete Tony More, now a chopper rescue paramedic in Taupo, finished seventh veteran and 25th male with a time of 9:17:34.
The Motu Challenge is raced over a body-sapping 172 kilometres of steep terrain, made up of 65km of Motu Road mountain biking, 17km of bush and gravel road run, 52km of road cycling including Trafford’s Hill, 27km of kayaking down the Waioeka River before a final 8km road ride and 3km run into Opotiki from the river.
Within the Motu Challenge are shorter multisport races, duathlon and bike race options, where Gisborne athletes have enjoyed success in the past.
In the teams’ race, the two-person team of Stephen Sheldrake and Louis McKenna combined in the Motu 160 (65 kilometres of mountain biking and 95 kilometres of road biking) to finish first in the male two-person teams category, winning by over 70 minutes with a time of 4:29:28.
Local triathlete Nan Baker finished as the second woman in the long-course duathlon. She finished the race, which shared the same mountain bike and run courses as the Motu Challenge and included an extra 90km road bike leg to Opotiki (no kayak leg), in a whisker under 9 hours.
Dougal Allan 1, Sam Manson 2, Bobby Dean 3.
Alison Wilson 1, Simone Maier 2, Elina Ussher 3.
Matt Backler 1, Blair Simpson 2, Matt Penney 3.
Simone Maier 1, Elina Ussher 2, Rachel Cashin 3.
Campbell Gray 1, Bailey Fredericksen 2,
Russell Smith 1, Peter O’Sullivan 2, Mike Scott 3.
Tanja Lempriere 1.
Lysaght Masters 1, Matt & Stew 2, Goose’s Team 3.
Teams, male 3- or 4-person: Team CRM 1, Bottom of the Barrel 2, Hear4U — Men’s Mental Health Awareness & Suicide 3.
Topsport Kayaking 1, Pedal Cartel — It’s on 2, The Big Dogs 3.
Greta & Hannah 1, Glittering Unicorns 2, Just Doing It 3.
Mark Jones 1, Darryl Bell 2, Tim Taylor 3.
Megan Farndale 1, Monique Geroghty 2, Helen Thoday 3.
Topsport Duo 1.
Alex Heaney 1, Nicholas Kergozou 2, Jan Lichtwark 3.
Georgia Perry 1, Kelsi Parker 2.
Team McDrake 1, Franz and Mal 2, Old Rebels 3.
Rachel & Sean 1, No Fear 2.
Galatea Boiz 1, Zane Boyle 2.
Penny Foggo 1, Nan Baker 2.
Jam 1.
Paul Terry 1.
Team AA 1, The Pretenders 2.