Sam McManis

Discoveries: At a park in Berkeley, kids wield hammers and saws with impunity ... while parents watch.

The sounds of children playing, those squeals of innocent delight and boisterous bleats of pent-up energy finally expelled, mingle incongruously with the percussive staccato of hammer meeting nail and the drone of saw on wood.

This cacophonous collision is something you rarely hear on a playground, particularly when it’s the kids themselves making noise normally produced by burly types wearing tool belts and carrying union cards.

Peer between the slats of the fence at the Adventure Playground, plopped between a parking lot and a kayak shed at the Berkeley Marina, and, yup, it’s confirmed: Kids are making all that racket. Little kids, too, some not even out of their training diapers. They frolic and gambol, as at any park. They climb a repurposed fishing net, zoom down a zip line and play pretend America’s Cup sailors aboard decaying wooden boats.

But they also are pretend construction workers, wielding hammers often as long as their forearms, clamping 2x4s into vises and measuring twice and cutting once. They brandish brushes and paint buckets, as well, slathering primary colors all over themselves and on asymmetrical structures that look like Jenga pieces run amok. They are given free rein, carte blanche. Want to build a plywood castle or wooden swords? Knock yourself out, little dude. Want to add some architectural flourishes to that house over by the zip line? Go for it, girl.

Truly, Adventure Playground is a park like no other. According to Patricia Donald, coordinator of the playground and Berkeley’s Shorebird Park Nature Center at the marina, it’s the only permanent hands-on building facility for children in the nation. It was recently featured in Architectural Digest, and Conde Nast Traveler named it one of the 10 best playgrounds in the world.

Fine, you think, but isn’t this most unusual city-run park a trip to the emergency room — and a lawsuit — waiting to happen? Rest assured, helicopter parents, that nearly all the children have a caregiver hovering close by, and also know that the playground’s teenaged staff members make the rounds preaching safety. In 35 years of operation, officials say, there haven’t been more accidents at Adventure Playground than at any of Berkeley’s 47 other parks — just the usual scrapes and the rare broken bone. Yeah, parents must sign a waiver, and the city pays liability insurance and all that. But, really, even the most anxious parent needn’t worry.

That’s because a big part of the experience at the playground is to sneakily instill a sense of safety in the little ones. Sneaky, because this lesson is cleverly disguised as fun. A hand-painted sign out front explains to kids “How to Earn Tools & Paint.” They must first scour the area and find 10 nails in the dirt, or five wood splinters, or five pieces of trash or one “Mr. Dangerous,” the latter being a piece of wood with a nail sticking up. Rather than being a chore, the sweep of the grounds becomes an adventure in itself for kids.

“I think they like the treasure hunt aspect of picking up the nails,” said Abby Scott of Piedmont, who brought her 9-year-old twins, one girl, one boy, to the park. “That’s as exciting as the reward.”

Does it teach them to pick up their rooms at home?

She laughed, then said, “Sure. They have to pick up at home before their next activity.”

Note that Scott and fellow Piedmont mom Sarah DeVan, who has three children, were chatting up your correspondent while simultaneously keeping close watch over their brood hunched over a wooden work bench, sawing and hammering their hearts out. Occasionally, DeVan broke away to tighten a clamp on a board. But, mostly, they let the kids alone to explore and create.

“Nails, hammers and saws are always exciting to kids, and they begged us to come,” Scott said. “What I like is just the ability to play in an open space where they can create in directed activities. Two of our girls are off on their own, but that’s because they aren’t playing with sharp objects.”

Indeed, Adventure Playground is more than just about manual labor. The zip line, supervised by park workers, whisks kids off on a 30-foot journey into a pile of soft dirt. The huge climbing net fastened to telephone poles, larger than a backyard trampoline, came from the Alameda Naval Shipyard. Among the other “play structures” is an old upright piano, tires, tubing, even a kitchen sink. And lumber. Lots of lumber.

The great thing about the playground, Donald says, is that it’s almost entirely made from recycled or re-purposed items. For instance, the shed that stores the nails, hammers, saws and paint was made from old shipping containers at the docks in Oakland. Donald said that was part of the plan 35 years ago, when a now-defunct San Francisco group called the Adventure Play Association pitched the idea to former Berkeley parks chief Frank Haeg.

“This was right after Prop. 13 hit and recreation programs took a dive and people were looking for new programs to serve those who didn’t have the money,” Donald said. “So (Berkeley) had an old parking lot and got the basic materials for putting a playground together. They got the phone company to sink in a couple of poles, which is the foundation. They got a bunch of lumber from old lumber yards, end cuts. People donated wood they didn’t want, and various materials. That’s basically all that was needed.

“Originally, there were 24 Adventure playgrounds (nationwide) in the 1970s. The idea came from post-war Europe, where kids really liked playing around in the rubble, creating their own fun. That’s what we like to do. We tell our staff there’s a fine line they have to walk. We want to keep it safe but don’t want to step on toes and stifle kids’ creativity. If a child takes a saw, we make sure they know how to use it and that a clamp goes with it. Some kids may not have backyards, and they may not have dads. They may not be exposed to things like this. This gives them the opportunity to play, but also get life skills.”

Eight-year-old Jake Morosini wasn’t thinking about life lessons as he balanced a nail between thumb and index finger of his left hand and brought the hammer down with his right. He just wanted to bang on things and make two pieces of lumber stick together.

His mom, Amy, nervously watched as the business end of the hammer struck the nail on its head, thankfully not Jake’s thumbnail. She exhaled audibly after he finished.

That’s another sound to add to the cacophony at the Adventure Playground — the collective sighs of relief from parents.