Tonks, seated on a raised platform in the middle of the boat, eases his trusty megaphone out from beneath the control panel and puts it to his lips. "Hooold the catch, niiice and relaxed, eeeasy on the oars," he murmurs, always placing emphasis on the first syllable when relaying the information.
The rowers respond, much to his satisfaction. Tonks contrasts his soothing, meditative instructions by edging up the throttle and pushing the coaching boat menacingly close to the duo's stern. That means the athletes are forced to move quicker or risk having their skiff - and pride - dented.
Tonks' methods are beyond dispute. Next to Arthur Lydiard he is arguably the finest sporting coach New Zealand has produced on the international stage. The 59-yearold has coached Olympic gold medallists at Sydney, Athens and Beijing and can count 11 world champion boats to his individual credit. Perhaps the most telling statistic is the 12 gold, four silver and four bronze medals New Zealand has earned at the four world championships since 2004, once Sparc money started to flow.
Most argue Tonks has the ability to pick up idiosyncracies and flaws within the rowing stroke as well as anyone in the world. He can immediately see if the catch of the oars in the water is not maximised or if a rower's muscles are under-utilised in a certain area. These days he also has access to the science as backup to the evidence he identifies with the naked eye. In essence he is a rowing doctor.
"Caroline and I were always in awe of his technical eye," says double Olympic gold medallist Georgina Earl (nee Evers-Swindell). "He would barely hesitate diagnosing what might be wrong with our set-up or what needed to change."
Tonks prefers to see his coaching in a wider context as building an aura around wearing the black singlet.
"Since 2000, we've trained as professionals but only since Athens did we really start to get any extra money.
"World championship winners do quite well now, they've got cars and other forms of sponsorship. They also don't have to get up at 6.30 in the dark on winter mornings. They can have a decent breakfast at a decent hour then train in the afternoon so they're not coming home after work, and facing more of the dark. "When rowers come into the squad these days, they immediately assume they are going to be good enough without needing any form of psychology. It's a case of believing that, when you wear the singlet, you are going to be competitive. It's taken us a long time to get back to that."
Tonks says the last time that occurred for a sustained period was in the aftermath of the Mexico City Olympics in 1968 when the coxed four of Dick Joyce, Dudley Storey, Ross Collinge, Warren Cole and coxswain Simon Dickie took New Zealand's first Olympic rowing gold. That was followed by the men's eight winning gold and a coxless four crew-featuring one R.W.Tonks as stroke - taking silver at Munich four years later.
Storey (70) sat directly behind Tonks in that crew. He says little has changed with the bloke he shared a double bed with 38 years ago.
"As the new boy in the crew perhaps he didn't want to do anything out of line because I could be stroppy - but he was a hell of a good roommate.
"Dick was never a flamboyant extrovert, like some rowers can be. He was quietly confident and reliable, which contributed to a great work ethic. He was always prepared to subdue flair and ask the question 'how do we make this boat go faster?'"
Storey says their crew came into the Munich final undefeated and the lead changed around a half dozen times before East Germany took out the race by just 1.37s, having edged into the lead 200 metres from the finish.
A rowing myth claims that result compelled Tonks to become such a successful coach, because he had identified the fine line between winning and losing in the toughest possible way. Storey says there is probably some merit to it.
"Look at the Evers-Swindell twins at Beijing [where they won, but it was the only time they were ahead in the race]. My guess is, somewhere in their preparation, Dick would have thought about what happened at Munich in 1972 and made sure it wasn't allowed to happen again.
"Mind you, he wouldn't have said a thing to those girls. You can't go to the start line with the thought of anything but gold on your mind."
Earl says Tonks was at his best on finals day.
"Caroline and I always appreciated the fact he was so relaxed. Whether or not he was, I don't know, but he knew we got nervous before getting on the water. There was never any hype on the day of our big events. He did all that sort of talk in the 10 days beforehand.
"He would always say 'you're not being judged on how you complete the event, like dressage in equestrian; you're being judged purely on who's quickest between A and B'. He would then hold his thumb and forefinger up with about one centimetre between them and say 'it could be this much' ... and in Beijing it pretty much was."
There is some irony that a 1cm victory can be related back to so many thousands of kilometres of training, up and down Lake Karapiro. But, rather than impart any complicated thoughts on the issue, Tonks says it is simple.
"Do plenty of miles because miles make champions. It might make you tired but, by persevering, you soon learn to relax and get the feel of the boat and the oars. You start to get more efficient, whereas over a shorter distance you can just slog it out with a limited technique. Going for a long row gives you a better rhythm and base fitness."
Tonks says that made the difference for the Evers-Swindells.
"Their training regime was phenomenal; way beyond the capabilities of most. There was no year I doubted they could win." The Evers-Swindells medalled every year in the premier international doubles sculls race of the season, except their first in 2000.
Tonks notes drily that Beijing was the classic example of their dedication.
"Moving past Germany would be the slowest overtaking manoeuvre I've ever seen. They were behind when they went to the line and after the line, but on the line they were in front. It was a mark of their training."
Rewards like the second Evers- Swindell gold medal have kept Tonks in a sport he never envisaged as a career.
"I thought it would probably ruin rowing for me if I did it as a job, but it somehow came about permanently from the end of 1999."
There is no reason why Tonks shouldn't continue to excel. His main vices at the time of print are the occasional slug of apple cider to keep the doctor away; the odd glass of red wine with dinner and a couple of gingernuts with his morning tea.
"I'm still enjoying it. It's not too bad out here, is it (he motions to a sunkissed lake with the mist starting to rise off the hills at 8.30am).
"Ah yes, sitting on the water waiting for the boats to return; it beats pushing paper in an office."
Sincere, brief and seated - as always.
