The weekend after Thanksgiving in 1898, New England was hit with a storm so fierce it sank roughly 150 ships and killed hundreds of sailors and passengers. It was nicknamed the “Portland Gale” after its most famous casualty: the SS Portland.

The opulent, 291-foot steamship had been ferrying passengers between Boston and Portland, Maine, for nearly a decade when it perished in the Atlantic along with every person on board, and the tragedy shocked the entire region—people later began calling the Portland “New England’s Titanic.” But while we know all about the iceberg that clobbered the “unsinkable” RMS Titanic, nobody’s quite sure why the reliable Portland was unable to weather the 1898 storm. In fact, for 91 years, nobody knew where it was.

The merry Portland illustrated in calmer waters circa 1890.Antonio Jacobsen, National Undersea Research Center, Wikimedia Commons // Public Domain

Oceanographic technology had advanced considerably by 1989, when divers John Fish and Arnold Carr teamed up with Richard Limeburner, an oceanographer at Woods Hole Oceanographic Institution (WHOI), to search for the sunken ship. They knew where bodies and detritus from the wreck had been found along the shore, and they knew what time the ship sank—the victims’ watches had all stopped ticking around 9 a.m. After estimating the shipwreck’s general location by tracing the victims’ paths in reverse, they used sonar to scan the ocean floor for signs of the ship itself. They weren’t disappointed.

The shipwreck rests in Stellwagen Bank National Marine Sanctuary, an area between Cape Ann and Cape Cod that’s home to approximately 200 shipwrecks. And although the researchers couldn’t prove their wreck was indeed the Portland in 1989, the National Oceanic and Atmospheric Administration (NOAA) confirmed it in 2002. Since then, there have been several expeditions to explore the remains, but none has solved the mystery of what caused its fatal plunge.

Next week, the NOAA and the WHOI are joining forces for a new expedition—and they’re livestreaming some of it.

The Portland's walking beam illuminated by an ROV called Pixel.Courtesy of Woods Hole Oceanographic Institution and NOAA

The first two 45-minute programs are airing on Tuesday, August 25, at 2:30 p.m. and 6:30 p.m. EST on both the NOAA and WHOI websites. Viewers will follow a remotely operated vehicle (ROV) as it inspects the Portland, while scientists narrate its progress and answer questions about the project.

They are, of course, hoping to find out why the Portland sank. An earlier investigation revealed that the crankshaft on the port side was disconnected from the connecting rod, which could’ve caused an engine malfunction. However, that may have happened when the Portland struck the ocean floor. It’s also possible that the ship exhausted its fuel source before it could make it to safety.

“We're still hoping to examine the boilers and see if there is any coal remaining,” Kirstin Meyer-Kaiser, the project’s lead scientist, tells Mental Floss. “If we cannot find any coal, this would suggest that the Portland had run out of fuel.”

An anchor on the upper deck, taken over by sponges, sea squirts, and lamp shells.Courtesy of Woods Hole Oceanographic Institution and NOAA

But the researchers aren’t only focused on filling in the Portland’s historical blanks. They’re also interested in studying its current role as a vibrant habitat for ocean life. For sponges, anemones, and other invertebrates that stay in one place—called sessile invertebrates—shipwrecks offer the chance to settle on higher ground, where ocean currents move more quickly and food floats by more often.

“We actually see some pretty distinct patterns in the Portland community,” Meyer-Kaiser explains. “There's a dense aggregation of anemones on the walking beam, the highest point on the wreck, because those animals are taking advantage of the food sources available to them there.”

The Portland's highest point, the walking beam, is a happening place for plumose anemones and other suspension-feeding species.Courtesy of Woods Hole Oceanographic Institution and NOAA

A shipwreck’s nooks and crannies are prime real estate for fish and other species seeking shelter, and the abundance of those species then attracts predators to the area. In short, shipwrecks are fantastic for biodiversity.

“This year, we had the opportunity to visit a natural boulder reef site and compare the biological community to the wrecks we're studying,” Meyer-Kaiser says. “The boulder reef community had some of the same species, but it was missing the large sponges, anemones, and many of the fishes we see on shipwrecks.”

An Atlantic cod caught in the headlights near a capstan on the upper deck.Courtesy of Woods Hole Oceanographic Institution and NOAA

Next week’s expedition will explore a second shipwreck, too: an unidentified coal schooner. Its hull is covered in a layer of copper to prevent biofouling, or the build-up of barnacles, algae, and other organisms that attach themselves to the submerged parts of vessels. Overexposure to copper can be toxic to marine life [PDF], and Meyer-Kaiser says the schooner’s layer has definitely kept its biological population smaller than it could’ve been. “It's actually fascinating to see anti-fouling measures working so well even a century or so later!” she says.

In addition to studying the biodiversity that is there, the researchers will also hunt for clues that might help uncover the schooner’s identity. They’ve spotted a shoe, a bowl, a speed-measuring device, an instrument they think is a telescope, and the numbers 898 nailed into the bow stem post. According to Meyer-Kaiser, this figure is a little like a house number or a license plate, and they’re sifting through historical records to find a match.

You can tune into the schooner expedition on Wednesday, August 26, at 2:30 p.m. EST and 6:30 p.m. EST, and on Thursday, August 27, at 2:30 p.m. EST, through NOAA or WHOI.