Inside the High-Tech Mission to Uncover Lake Union’s Sunken History

If you’ve spent any time on the water lately, you might have caught sight of an engineering team operating what looks like a mini high-tech navy from the shoreline. Phil Parisi is the driving force behind Shipwreck City, a volunteer-run project using underwater robotics to build the most comprehensive archive of Lake Union’s sunken history ever attempted.

For those of us living on floating homes, the lake is our neighborhood, our backyard, and our floorboards. But to Phil, an engineer by trade, it’s a living museum hidden under forty feet of dark water and silt. 

And according to his latest data, that museum is crowded.

Drones, Deep Water, and the Road to Seattle

Phil didn’t grow up with flippers. A self-described "Chicago kid from the suburbs," his relationship with autonomous vehicles started on land and in the air, building aerial drone frames and working with unmanned systems at Sandia National Lab in New Mexico. But a desire to write the “backend algorithms for more rugged environments” (as he puts it) eventually drew him east to Rhode Island, where he fell in love with ocean engineering.

"The deep ocean is the last great wilderness on Earth," Phil says, describing his time working alongside oceanographers and biologists, using cutting-edge environmental DNA (eDNA) sampling to map marine ecosystems -- all without having to capture a single fish.  

After a stint at the Pacific Northwest National Laboratory (PNNL) in Sequim, Phil moved to Seattle and founded a maritime consulting company that supports large-scale Navy robotics operations. But that’s just the day job. His passion lies much closer to home: exploring and understanding the hidden world beneath the surface of Lake Union.

 Continuing a Tradition of Discovery

The idea for Shipwreck City didn't happen in a vacuum. About a decade ago, Ben Griner of Coastal Sensing and Survey ran an extensive side-scan sonar map of the lakebed, identifying over a hundred anomalies—shapes that looked man-made but had never been visually confirmed. While local dive groups successfully cataloged a few of the famous, large wrecks over the years (like the Gypsy Queen or the J.E. Boyden), a massive gap remained. Roughly 70 to 80 shapes in the mud were left completely unverified.

"We don’t know what’s in one of the most utilized lakes in the center of Seattle," Phil says. "That struck a personal cord with me. And it’s not even that deep."

Because recreational diving in Lake Union is heavily restricted by Harbor Patrol due to seaplanes, rowers, and heavy vessel traffic, the targets sat undisturbed. And you don’t want to muck up the bottom of the lake and release any old chemicals lurking below.  

That’s where Phil's robotics background came in. Partnering with a company called Blue Robotics and with permission by Harbor Patrol, he began deploying a Blue ROV2—a remotely operated underwater vehicle with 600 feet of tether—and an autonomous pontoon surface vessel called the Blue Boat.

Before dropping his first robot in the water, Phil connected with local history advocates, including filmmaker Vaun Raymond, creator of the Lake Union Virtual Museum. Raymond's pioneering work laid the digital groundwork for Shipwreck City, which has since expanded into a popular YouTube channel with nearly 13,000 subscribers tracking the team's weekly underwater updates.   His video from five months ago already has 39,000 views.

First Dive, First Discovery

If anyone doubted how much history is still hiding down there, Shipwreck City’s very first expedition settled the score. Setting up near Gasworks Park, the team dropped the ROV into an area where official maps recorded exactly three known wrecks.

Within minutes, the camera fed back an image of a fourth, completely undocumented shipwreck tucked away in the lake weeds.

"It was almost comical how off the bat we found something new," Phil laughs. After consulting with local divers to make sure they weren't seeing things, the discovery was confirmed.

According to the project’s live database at ShipwreckCity.org, the effort is currently 58% complete. Of the 105 known lakebed targets they are tracking, the team has explored 61 sites, confirming 40 distinct wrecks—including three entirely new discoveries that historical records missed entirely. The items range from old wooden barges and landing craft to historic vessels like the Onondaga, a 165-foot former Coast Guard cutter and Arctic explorer.

What’s Under the Houseboats?

For members of the Floating Homes Association, the most intriguing part of the project involves the waters right beneath our homes.

Traditional, boat-based sonar sweeps are bound by physics; they have to stay out in navigable channels, and their signals are blocked by the dense rows of pilings and houseboats lining the shore. Phil’s tethered ROV, however, is nimble enough to slip directly beneath docks and marinas to see what has slipped through the cracks of neighborhood history over the last century.   He is game to take a look if residents think there is something down there.

The project has garnered widespread support from local heavyweights, including the Museum of History & Industry (MOHAI), the United Indians of All Tribes Foundation, and the Puget Soundkeeper Alliance, all of whom recognize the value of preserving this underwater historical record before time and decomposition erase it forever.   Of course, he’s also connected with Floating Homes historian Adam Woog, as well as Derek Voelker of Seattle Dive, and Floating Homes president Stafford Green.   

If you are looking to see more of the media coverage and video footage of the ROV dives, you can also check out the KING 5 Feature Story, “Sonar and robots reveal Seattle’s hidden 'shipwreck city.’”

How the Floating Homes and Lake Union Community Can Help

Shipwreck City is an entirely volunteer-driven labor of love. As Phil sets his sights on solving the remaining anomalies—including a highly unusual, mysterious 12-foot structure currently logged as Target LU073—he’s looking to the floating home community for a few things:

• Local Lore and Tips: If you know of an old pleasure boat, an ancient dinghy, or a historic piece of dock infrastructure that sank near your slip decades ago, Phil wants to hear about it:  Contact Phil

• Support their Volunteer Efforts by donating here: Shipwreck City Donation Portal. 

The next time you look out over the water from your deck, remember that there is an unwritten chapter of Seattle history resting just a few dozen feet below.