So Tonks will leave after Rio, presumably with no shortage of future suitors. He has mentored five crews to victory at the past four Games, with two incumbents in the offing.
Opinions on his exit will vary between calling it a travesty, a relief or a necessity. None will question his record. Since taking up full employment in 1999, Tonks' Olympic success rate has surpassed the late Arthur Lydiard who picked up four golds (Peter Snell 800m 1960, 1964; 1500m 1964; Murray Halberg 5000m 1960) and one bronze (Barry Magee, marathon 1960). Boardsailing mentor Grant Beck has three golds (Bruce Kendall 1988, Barbara Kendall 1992, Tom Ashley 2008), one silver (Barbara Kendall 1996) and three bronzes (Bruce Kendall 1984, Barbara Kendall, Aaron McIntosh 2000).
New Zealand rowers have also secured 68 Olympic or world championship medals since the Athens Games of 2004. Tonks has helped make household names of Rob Waddell, Caroline Meyer and Georgina Earl (nee Evers-Swindell), Drysdale, Hamish Bond and Eric Murray.
A dichotomy is also at work; Tonks appears to get on with his former female success stories, albeit with most considering him a coach, rather than a friend.
Philippa Baker-Hogan, a triple world champion under Tonks in the 1990s, described the phenomenon of working with him in a Fairfax column last December during his stoush with Rowing New Zealand.
"A Tonks rower can have a smile a mile wide, simply from receiving a positive grunt from him after a killer workout, when other coaches will say a thousand words to demand the same respect.
"He is as happy coaching a committed young club rower as an international and if you really knew him, you would trust him with your life."
That sense of loyalty is shared by Earl and Meyer. "I wanted him to be there on the finish line to give him a hug, but apparently he couldn't watch," Earl said of their Beijing Olympic victory. "It was a buzz to get back to him. He'd been through all the training and we wished he could stand on the dais with us."
The relationship remains cordial from afar. "That was the case when we were rowing, too," Meyer said. "If I see him at a regatta in Twizel, I go up and give him a hug.
The same cannot be said for all their male counterparts.
If claims by broadcaster Tony Veitch are true about "Chapter 14" of Murray and Bond's upcoming book, Tonks' personality and modus operandi are set to receive a post-exit boot out the door. If that's the case, it verges on disrespectful. However, Bond and Murray will be in a strong position to critique Tonks if they win a second Games gold this week. They will have won one with his mentoring and one without.
Contrast that with Drysdale, who exited Tonks' regime to be coached by Calvin Ferguson in 2007 and 2008. He reverted back to Tonks for the 2012 Games campaign.
If anecdotal evidence is to be believed, athletes have gone through hell under Tonks at times, but surely they had a choice.
Possibly less so in earlier years when he was "the programme", but certainly later as Rowing New Zealand's operation expanded and their coaching base diversified, especially with $32 million in taxpayer funding this cycle. Four of their other coaches - Noel Donaldson, Ferguson, Gary Hay and Dave Thompson - earned medals at last year's world championships.
"The culture has built slowly through winning," Tonks said before London. "Anyone who joins this programme has to believe they're good enough. That means they don't sit on the start line, look across at the Germans, the English, the Americans and the Russians and think, 'Aw, hell'. Those other crews have to look at our black singlets and know they're going to be under threat."
Regardless of anyone's thoughts on Tonks, he ensured rowing became more than a cottage industry in this country. The medals should roll in this week across New Zealand's 11 classes. The athletes will be lauded, and rightly so, given the toil they have invested.
But, hopefully, as the breathless reports flood through from Lagoa Rodrigo de Freitas, someone will have the grace to acknowledge that Tonks' genius also deserves a place on the top of the podium.
