Family and friends gathered at Woodlea farm on Hodders Rd yesterday and Carterton fire chief Wayne Robinson, a longtime mate, said there was disbelief and confusion about the circumstances of Mr McLennan's death.
"You couldn't get a more safety-conscious person than Hamish. He wouldn't do anything remotely dangerous to himself or anyone else. That's why it comes as such a surprise where the bike's ended up, where he ended up.
"That's why the question has to be asked, how did he get there?"
Mr Robinson said his friend had left home about 8am on Tuesday with about 80 litres of chemicals in a sprayer unit aboard the quad. The alarm was raised after he failed to return by mid-afternoon.
"A couple of workers and a neighbour went out looking for him. Emergency services were called when he was found but there was nothing they could do. He had the bike on top of him in two or three feet of water.
"It's a property of at least a couple of hundred hectares, reasonably sized, and this time of year most everything is dried up. There's only really the one area of water, near where he was spraying," Mr Robinson said.
"But where he was, everybody said he wouldn't be there - the terrain, for about a 50-metre area, was too rough for him to be there - and whether something's happened, a medical event maybe, will be for the coroner to say."
Mr McLennan ensured "safety was paramount" on the property, Mr Robinson said, with his workers instructed to wear helmets when riding quad bikes in some areas of the farm.
Mr Robinson, who visited the farm about noon on Tuesday as an agent for an agricultural supply firm, said Mr McLennan had been farming at Dalefield for up to three decades and was a well-liked and respected member of the Carterton and Wairarapa farming, horse sports and hockey communities.
He was a founding member about 25 years ago of the successful Dalefield Premier men's hockey team alongside Mr Robinson.
Mr McLennan played social hockey until at least two years ago, and had also completed a long-distance run around Lake Taupo. A sharemilker was hired at Woodlea to give him more time for his sport and recreation.
"He liked to stay fit and healthy and was the sort of guy who would always stop and talk if he saw you on the road. Nobody would have a bad word to say about him, for sure. He was very much liked and respected and will be sorely missed."
A funeral service will be held for Mr McLennan at St Mark's Anglican Church in Carterton at 1.30pm tomorrow.