We see it, smell it and travel across it every single day. Europeans settled Halifax solely for its grand natural harbour. What do we really know about what’s beneath its surface?

Bob Chaulk has seen the underbelly of the beast more than most of us have glanced at its face. Sharks, shipwrecks and shrapnel; ammunition, cars, and one grim time, a body: these are just some of the things Chaulk has found beneath Halifax Harbour.

He’s a 64-year-old Newfoundlander who’s lived in Halifax for the past 34 years. He’s dove under the surface of the city’s harbour more times than the average urbanite has done so much as look at it. “I like diving because it’s so intense,” he tells me. “I could be down in the Narrows with two tankers going over me in a pretty strong current, with my heels stuck in the bottom. It’s all a calculated risk.”

There’s nothing particularly striking about Chaulk when you first look him. He’s been married to the same woman for 44 years, lived in the same house for 34 years, and raised two boys. He’s the patriarchal picture of a picket-fence nuclear family. But, like the waters he spends so much of his time in, once you penetrate his surface, the stories begin to bubble up.

“The [naval] Dockyard is scary,” Chaulk says. “There’s so much stuff down there that, you know, probably shouldn’t be disturbed.” He leans in, his voice quieting. “Big batteries, lots of ammunition, military ammunition—bombs, artillery shells, empty ones and full ones, and depth charges. Once every five or 10 years the navy announces they’ve cleaned it all up,” His brow creases. “How can you possibly clean it all up?”

Chaulk is floating somewhere around the 2,000 mark for his dive tally, since he took his first plunge back in 1987. “I dive a fair amount,” he says. “An average, active diver would do a dozen dives a year. I think so far this year I’ve done 45 or 46.”

His biggest fascination with the harbour’s waters is not the wrecks or the tons of ammunition from wars-past, nor is it the flora, the fauna or the inner workings of deep-water ecosystems. Chaulk looks for the type of thing that got there because it was considered garbage in the first place.

“I don’t even pay attention to most of the stuff [down there] because I’m looking for specific things,” he explains, gesturing to the fraction of his collection on his mantle. “I’m looking for bottles and I’m looking for dishes. And I’m looking for things that are old—pipes and crockery and brass.”

His longtime work partner-turned-friend, Ron Stuart, tells me he has no interest in diving himself, (“I tend to sink”), but Chaulk’s stories fascinate him. “I’m interested in what he’s learned about Halifax businesses that are now long gone, just though his bottle collection,” he says. “He knows about dairies and beer manufacturers, all because he found bottles in the Halifax Harbour.”

Chaulk has recovered about 25,000 bottles over the years. The most expensive one checks out for about $2,000, and one of his oldest finds dates back to the 1500s. (But he found that one off the coast of Newfoundland). He’s interested in wrecks. It’s just hard to find ones that haven’t been reduced to piles of barnacled steel or bits of rotted wood (not to mention, almost everything in the Halifax Harbour is buried beneath some seven metres of silt).

“People think wrecks are little ships sitting on the bottom,” he says. “They’re not. They’re smashed up, for two reasons: because of the weather here, and because they’re often salvaged. All the wrecks off of here have been blown up. It’s just a debris field.” Though there are wrecks in the Narrows and in the Bedford Basin, many lie a bit further down towards the mouth of the harbour. “Most of the wrecks are outside of McNab’s Island,” Chaulk says.

Our interview is briefly interrupted by a knock on the door—someone wishing his wife Sandra a happy birthday. When Chaulk returns, his hands are full with books and articles he’s authored over the years, and he fans them out on the table, pointing to his favourites.

He’s written the books Time in a Bottle: Historic Halifax Harbour from the Bottom Up, and The Chain Locker. He is also the co-author of S.S. Atlantic: The White Star Line’s First Disaster at Sea, which he wrote with late fellow diver and friend, Greg Cochkanoff, who now rests peacefully in the brisk waters off the coast of Nova Scotia, where the book’s namesake sank. “Greg’s ashes are buried on the SS Atlantic,” Bob recalls. “We put him down there in the boilers. And, as far as I know, he’s the fifth guy that’s been buried down there. The Atlantic is a special wreck.”

There’s nothing flashy or over-romanticized about Chaulk’s life. In his home, the clock ticks, the fridge hums, the landline phone rings a couple times an evening. But it’s his personal victories and fearless demeanor that make his life so extraordinary to an outsider.

He has swum beside freighters the size of football fields, stared barracudas in the face, and even came across the body of a bridge-jumper once. “Bob has zero fear of the water,” Stuart says. “Maybe some of that comes from his Newfoundland heritage and being on or near the water most of his life. He is endlessly curious. He has an insatiable desire for information, and when he gets on to something he just wants to go into it deeper and deeper and deeper.”

Chaulk took up diving on his own after graduating university, getting married, travelling the world and learning to fly a plane. Last year, he scratched off a longtime item on his bucket list and built his own boat. “I was thinking [about my bucket list] and the things they say to you: ‘do that project you want to do, write that book, do some travelling,’ and you know, I’m darned if I know what I want to do next,” he says.

Chaulk’s memory is filled with shipwrecks, artifacts and wildlife, all teeming just metres below the harbour’s gray face. And, in the basement of his home, he has a meticulously curated collection that matches up with his recollections perfectly. And he’s continuing to add to those memories. “If you cross the Old Bridge on a Sunday or Saturday morning and you look down and see a bunch of little boats, that’s probably us.”