Bike Contraption Whistles with the Movement of the Tide

Bikes Craft & Design Music
Bike Contraption Whistles with the Movement of the Tide
All photos: Nathan Hurst/Maker Media
All photos: Nathan Hurst/Maker Media

You may not have heard of a Bosun’s whistle, but you’re probably familiar with a lot of its language. Originally used by medieval navies, the small brass whistle is made to be played in different patterns and pitches. It communicates signals like “still,” “carry on,” “dinner call,” and “pipe down.”

Bosun’s Bass is like a giant, highly-engineered art whistle that is not used to communicate, except maybe to teach visitors to San Francisco’s Exploratorium about the history of Bosun’s whistles. Created by Tim Hawkinson for the Exploratorium’s “Over the Water” series, Bosun’s Bass uses a shipping container and a bellows from a city bus to push air through an old women’s Huffy Easy Rider bike frame.


The whole installation is meant to leverage the tide. The incoming tide — twice a day — increases pressure on four tubes installed within the shipping container, which sits suspended with its end in the water. That pressure inflates the bellows, on top, and when it is turned on, weights press down on the bellows, forcing air through tubing to the bike. It coos like a pigeon, three octaves lower than the brass whistle Hawkinson carries.

On the bike, Hawkinson installed mechanical devices to control the airflow. A copper water tank float acts as the echo chamber, with a flapper to change the pitch. A piece of silver dryer hose acts as a mini bellows, and a pink ball in a Sriracha bottle bounces to give a trill. The rear tire is cut out, and the patterns on it are encoded to trigger the different types of calls, 21 in all, as it rotates.

Bosun's whistle tide bike art installation

Hawkinson worked on the installation for about six months and used a crane to place it in a hole in the pier on the San Francisco Bay. The elements each represent an aspect of the region, from the busses that go by, to the shipping containers being offloaded over in Oakland, to the cycles that pass on a nearby bike path.

“My way of working is not really scavenging, but using whatever is readily available, and fits the tone,” says Hawkinson. For example, he needed to vary the speed the flapper moved, and chose a flywheel from a music box to perform that task. “There’s probably a better way of solving that, a damper or something, but I try to rely on what I know,” he says. “That gets me in trouble sometimes.”

Hawkinson plays a Bosun's whistle. Photo: Nathan Hurst/Maker Media
Hawkinson plays a Bosun’s whistle. Photo: Nathan Hurst/Maker Media

1 thought on “Bike Contraption Whistles with the Movement of the Tide

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Nathan Hurst is an editor at Make. He loves anything having to do with science or bicycling. He tweets as @nathanbhurst.

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