Divers mapping a cannon and preparing to lift it to a University of Maine research vessel. Credit: Courtesy of Warren Riess

Scuba divers in Maine waterways brave chilly, murky waters for a chance to glimpse submerged historical shipwrecks.

Some make a hobby of checking out these wrecks and sometimes collect trinkets along the way, but archaeologists and historians worry that amateur aquatic exploration could compromise important sites for the history of Maine.

Paul Rollins, owner of Rollins Scuba Associates in South Portland, has been exploring shipwrecks off of Maine’s coast for about 30 years. He estimates that he has dived on 20 to 25 shipwrecks, from Boon Island to Penobscot Bay.

Rollins said there are a wide variety of shipwrecks off the coast of Maine, from wooden ships chewed away by marine critters like shipworms to steel vessels from more recent periods. He even teaches a class on shipwreck diving for recreational divers that outlines the history of Maine shipwrecks and how to lift, clean and preserve objects found in them.

“What you want to do is preserve the stuff correctly and not have it fall apart and have it become trash,” Rollins said. “It’s mostly look, don’t touch anything, until I show you how to touch it, maintain proper buoyancy and have fun.”

Chip Lagerbom, maritime historian and teacher at Belfast Area High School, is one of the founders of a group of recreational divers called the Aquanuts, which regularly explores Maine shipwrecks.

The Aquanuts have been cataloging shipwrecks in Penobscot Bay using historical records from libraries, museums and historical societies, as well as local word of mouth. Most of the 400 wrecks in the database are “rough remains” — timbers, engines and debris — from the 18th to 20th centuries.

Some wrecks haven’t even been located yet, and the information about them is solely based on historical records. There is always potential for the Aquanuts to find new wrecks and uncover more pieces of the historical puzzle through diving.

“A new wreck for the database might be one that someone stumbles upon, either by research of records and historical sources or by encountering something underwater,” Lagerbom said.

Some Mainers have made a career out of piecing together the historical record through shipwrecks. Warren Riess, research professor emeritus of history at the University of Maine, has studied Maine’s shipwrecks for decades.

He said Maine is a rich area for shipwrecks, and the artifacts left behind can provide significant insight into the way people lived throughout history.

“Whether you’re coming or going to northern Europe, you’d be coming right along the Maine coast and of course a storm could push it in,” Lagerbom said. “What we have is a cross-section of vessels. Shipwrecks are different from land sites — not only physically, but the information they carry is international.”

Shipwrecks preserve elements of historical artifacts that the land does not, which helps paint a more complete picture of life in the past. On land, you might find the ax head but not the handle, which has been eaten away by organic forces. Underwater, you might find the handle preserved by the salt water, which has instead worn away the metal head.

“It’s very synergistic or complementary to land archaeology,” Riess said.

However, tensions can arise between recreational divers and professional archaeologists when it comes to exploring shipwrecks. Maine has laws in place that restrict diving on certain shipwreck sites if they are deemed of archaeological value, so many divers are hesitant to share their favorite shipwreck locations.

Just the act of moving flippers and kicking up sediment while diving can compromise a shipwreck site. Sometimes, divers also like to recover treasures from the shipwrecks, which makes it harder for archaeologists to piece together a historical narrative.

“When you approach an archaeology site you have to be more ethical than any other science,” Riess said. “If I’m doing a physics experiment or chemistry experiment and I screw it up, I can do it again. In archaeology, we destroy the site as we go. At an archaeology site, you really have to be guided by someone who knows what questions to ask.”

However, Rollins said many sites would never have been found in the first place without the exploration of recreational divers.

“If it weren’t for divers in general you would very seldom have any idea where there are archaeological sites,” Rollins said. “It’s the divers that generally discover them and turn them over to the state.”

Rollins has donated items to the Portland Headlight Museum that have been on display in its collection. Even Riess admits that more than half of the vessels he has studied have been found as a result of somebody stumbling upon them.

Even if the state deems a site of archeological importance and restricts it to divers, it might not have the resources to study the site before it is compromised by natural underwater forces.

The process is extensive, from analyzing the site once it is found to determine whether it is of archaeological significance and worth the exorbitant price tag — often several million dollars — of exploring and conserving it.

Riess said excavating a shipwreck takes about 15 years on average and requires expensive equipment and specialized training.

Lagerbom understands both sides of the debate. He said the Aquanuts are judicious about what items they take from the floor of Penobscot Bay.

“If we do retrieve something it’s usually from a debris field,” Lagerbom said. “The [historical] context is not there. It’s not in a shipwreck, it could have been brought in by the tide.”

Those items are cleaned, photographed and sometimes compared to known objects.

Correction: Warren Riess’s last name was initially misspelled. It has been corrected.