Underwater archaeologists build 3D models of Thunder Bay shipwrecks

2Grobotics_Monohasset2Underwater archeologists have added a new tool to their arsenal as they examine shipwrecks in the Thunder Bay National Marine Sanctuary: lasers.

The lasers are being used to create 3-D models of shipwrecks near Alpena.

On board the research vessel The Storm we made several passes over the wreck of The Monahansett to collect data for a 3D image the crew will put together later

John: “Whatever you do don’t fall off the boat.”
Ben: “Okay.”IMG_7855
John: “Please.”

The man who requested I don’t fall off the boat is John Bright. He’s a maritime archaeologist at the Thunder Bay National Marine Sanctuary.

He said traditionally, the work of surveying and mapping wrecks requires putting divers in the water.

“In a lot of these sites we can put divers in the water to map them but it’s fairly time consuming to do that. Divers have to pull measuring tape, they have to plan dives working with a buddy team underwater. They’re limited by the gas supply they can take with them, how cold they get. With this mounted to a boat we can just drive and drink coffee on the surface and get the same amount of data.”

The laser technology comes from the Canadian company 2G Robotics. It’s a huge step for underwater archaeology.

Bright explained how it works.

IMG_7878“We are using a prototype underwater laser scanner that combines a laser imaging system with an underwater photography system to image shipwrecks on the bottom of Lake Huron. It operates in two ways: the laser scan generates a 3D point cloud and the photographic system takes images that it overlays on the point cloud to generate a surface that looks much like it would look if you were to see it with your own eyes.”

The catch is the system only works at night because the laser scanner is disrupted by sunlight. So The Storm has been running night trips from 8 in the evening to somewhere between 4 and 6 in the morning.

Once we got out on the water the crew lowered the laser and camera, hooked on to the end of metal scaffolding, into the water.IMG_7891

John Lee with 2G robotics took me to the side of the boat so I could see the laser.

“So there’s a 50 degree swath that goes down. It starts as a single beam and then it goes through a prism.”

Beneath the boat water glowed with an eerie light that, to me, looked purple.

Ben: Is there a reason it’s purple?
John: It’s blue actually. We have three different laser models, we use the blue light because it’s intensity is the greatest.

2G Robotics donated its time and resources to the marine sanctuary… both to help researchers uncover what’s lurking just below the surface, and to test out their latest products. Jason Epp with 2G Robotics said the laser technology is about five years old, but the technology that creates photo mosaics is brand new.

He said the total package won’t come cheap when it hits the market later this year.

“Our system I believe the complete payload will be in the $200,000 dollar range.”

IMG_7903That price tag makes the technology cost prohibitive for anyone other than the oil companies it’s built for. They would use it to inspect underwater pipelines for problems.

When we finally got out to the Monahansett, a wooden steam barge that wrecked in 1907, we started our first pass over the ship. One of the crew played Daft Punk’s ‘Doin’ it Right’ in the background.

“Alright guys, start logging.”

On the screen you could see the lake floor stitched together in real time, 30 thousand laser points a second creating a 3D image on a laptop. And then…as the boat began to come together onscreen, the propeller, boiler, chunks of wood and an anchor quickly formed the remains of a ship. John Bright with the Thunder Bay Marine Sanctuary said this is a classic case where technology improves efficiency.
“It can take hours and hours and hours for an entire team pulling measurements, drafting those measurements, setting a reference point that those measurements are from and then going in on a drafting table and putting that all together.”

The view from the top is drastically different from what divers must feel. But even that, standing safely on a ship above the wreck, cup of coffee in hand, as the ship materializes on screen, still has the excitement of discovery.

If you’re interested in seeing the completed images of photos and 3D modelling they will be posted as available on: https://twitter.com/thunderbaynms?lang=en