Bowater was at it again following a turnover to deliver a reverse inside ball for fullback Ethan Robinson to dive under the sticks, and then the young flanker himself scored under the black dot after an intercept inside the 15m.
Desperate to get out of their own dangerzone, Ruapehu again lost the ball and centre Dillon Adrole was there to dive across.
Ruapehu scored a consolation try through their forwards with skipper Gabriel Hakaraia forcing his way over, but the visitors would have left Whanganui disappointed they could not put more of a break on the teams sitting 1-2 points behind them.
Marist gave a much stronger effort at Spriggens Park against table leaders Waverley Harvesting Border than they did in the 79-19 mauling on July 25 at Dallison Park, but the result was still the same – nothing to show in the 44-10 loss.
Border are now well odds-on to retain the Grand Hotel Challenge Shield for another season although the South Taranaki club has a slight paranoia about that - given every season they finish the year with the shield they don't go on to claim the Premier title.
The visitors led 17-5 at halftime and then pulled away in customary fashion, with winger Isaiah Graham-Hooper and fullback/midfielder Nick Harding both scoring doubles.
Of perhaps a slight concern for Border heading into finals rugby is the goal kicking, with only two conversions for their eight tries.
Loose forward Semi Vodosese and halfback Lindsay Horrocks continued their profitable season with tries, with Tyrone Albetr and James McDonald also crossing the line.
Back from suspension, Josaia Bogileka scored for the home side, as did Cajun Teki-Botica.
In the Senior competition, over half the games were won by the side trailing at halftime, none more historic than Gemini Pepper Construction Kaierau picking up a victory over a decade in the making by finally beating Kelso Hunterville 22-3 at the Country Club to stay in touch with the Top 2.
Hunterville scored the only points of the first half with a successful penalty from two attempts, before Kaierau struck back with a converted try and drop goal to lead 10-3.
Entering the final 10 minutes, it was the home side who had composure while the visitors made uncharacteristic mistakes, as Kaierau scored two more tries, the second right on fulltime which actually left them disappointed despite the milestone win, due to missing a crucial bonus point.
They will now face undefeated Harvey Round Motors Ratana for the Stihl Shop Wanganui Challenge Shield, after Ratana ran riot in the second half at the Pa to beat Border 67-9, moving to the top of the table.
Although needing a lot of mathematical equations to go their way, Utiku Old Boys remain in contention for the Top 2 for another week after coming from nine points down at halftime to get home 24-21 against the Marist Buffalo's at Memorial Park.
It was a similar story at Spriggens Park, where Speirs Food Marton continued their late season revival by hauling in a 10-point halftime deficit to beat Black Bull Liquor Pirates in a 27-25 thriller.
At McNab Domain, home side Counties confirmed they are safe from wooden spoon territory by just holding off Bennett's Taihape 22-19, after the visitors have given a couple of their backs to their Premier squad playing up in the Waitotara Valley.
Results, August 29
Tasman Tanning Premier, Week 9
Grand Hotel Challenge Shield – Waverley Harvesting Border 44 (Isaiah Graham-Hooper 2, Nick Harding 2, Lindsay Horrocks, Tyrone Albert, James McDonald, Semi Vodosese tries; Harding 2 con) bt Dave Hoskin Carriers Marist 10 (Josaia Bogileka, Cajun Teki-Botica tries). HT: 17-5.
Wanganui Car Centre Kaierau 40 (Clive Stowers, Josh Lane, Dylan Bowater, Dillon Adrole, Fa'afatai Pulemagafa, Ethan Robinson tries, Robinson 5 con) bt McCarthy Transport Ruapehu 14 (Takarangi Metekingi, Gabriel Hakaraia tries; Kahl Elers-Green 2 con). HT: 7-5 Ruapehu.
Byford's Readimix Taihape 77 (Dylan Gallien 4, Tyler Rogers-Holden 2, Dane Whale, Ryan Karatau, Tiari Mumby, Hadlee Hay-Horton, Tyresse Payne, Lennox Shanks, Te Rangitapu McLeod tries; Whale 5 con, Ritchie Iorns con) bt Settlers Honey Ngamatapouri 17 (Timoci Seruwalu, Epeli Delisau tries; Hone Taurua pen, 2 con). HT: 26-17.
Senior Championship, Week 9
At Spriggens Park: Speirs Food Marton bt Black Bull Liquor Pirates 27-25. HT: 17-7.
At Kaierau Country Club: Gemini Pepper Construction Kaierau bt Kelso Hunterville 22-3. HT: 3-0 Hunterville.
At Ratana Pa (Stihl Shop Wanganui Challenge Shield): Harvey Round Motors Ratana bt Border 67-9. HT: 10-6.
At McNab Domain: Counties bt Bennett's Taihape 22-19. HT: 12-10 Taihape.
At Memorial Park: Utiku OB bt Marist Buffalo's 24-21. HT: 14-5 Buffalo's.
Bye: Ali Arc Logistics-DNA Kennels Marist Celtic.
Around the grounds
Collegiate
Whanganui Collegiate 1st XV are undefeated top qualifiers out of the Central North Island's South pool after a dynamic 25-17 win over rivals Feilding High School at the school grounds on Saturday. Getting revenge for the 13-8 loss in Feilding last year, Collegiate turned around a 12-10 halftime deficit to finish the stronger. They wait to see who their semifinal opponent from the North pool will be, due the delayed match between St Peter's Cambridge and Wesley College because of Auckland's Level 3 lockdown.
Cyclones
Three members of the St Johns Wanganui Metro Women's team have been named in the wider 30-women Manawatu Cyclones squad preparing for the Farah Palmer Cup. Former Black Fern Sosoli Talawadua had already been taking teenager Montel Vaiao Aki with her to Palmerston North for high performance training, but joining them now is Metro team mate Lavenia Nauga-Grey. The season kicks off in September.
Steelform Wanganui
The invited 2020 wider Steelform Wanganui squad will muster this Wednesday at Cooks Gardens. Forwards: Tai Pulemagafa, Wiremu Cottrell, Kamipeli Latu, Gabriel Hakaraia, Hadlee Hay-Horton, Dylan Gallien, Joe Edwards, Jack Yarrall, Josh Lane, Jack Hodges, Brad O'Leary, Matt Ashworth, Jamie Hughes, Angus Middleton, Dylan Bowater, Campbell Hart, Cade Robinson, Lennox Shanks, Semi Vodosese, Samu Kubunavanua, Ranato Tikoisolomone. Backs: Lindsay Horrocks, Cameron Davies, Tyler Rogers-Holden, Dane Whale, Craig Clare, Ethan Robinson, Troy Brown, Timoci Seruwalu, Dillon Adrole, Josaia Bogileka, Vereniki Tikoisolomone, Karl Pascoe, Tom Symes, Alekesio Vakarorogo, Cody Hemi, Nick Harding.