Wisconsin’s UNDERWATER HERITAGE Vol.12 No. 2 A publication of the Wisconsin Underwater Archeology Association June 2002 The Impacts of Zebra Mussels on Shipwrecks by John Karl the zebra mussel colonies. monitoring material. They are recov- Underwater These findings findings strongly ering one table from each wreck per suggest that the dissolved iron is year, for six years. Preservation in coming from the zebra mussel colo- So far they have pulled up tables nies, and thus from the iron fasten- for two years. They found that zebra Wisconsin ings to which they are attached, mussels settled on all of the plates, by Bob Korth, Watzin and Cohn argue. The research- but the largest number settled on the WUAA Director ers note, however, that these studies wrought iron and steel rods. The few- do not offer information on the rate of est mussels settled on the hot-rolled une 2nd 1969, a gentle swell corrosion. Ongoing studies will assess steel plates. on Lake Michigan rocks an 18 these rates. Most of the plates and rods on the Jfoot boat cruising a few miles Settlement Experiments. Cohn and tables showed general corrosion and off Two Rivers, Wisconsin. Two Watzin also conducted experiments to pitting of up to 1.0 mm deep. The divers line up land marks on the quantify rates of zebra mussel coloni- researchers noted that the length of distance shore and a Vexlar zation on materials typical of those their reporting period was insufficient recording sonar, tracks the bot- found on shipwrecks in the lake. The to allow an estimate of the rate of cor- tom looking for the remains of team set out six "tables" of mesh wire rosion. the 500 ton, 180 foot Schooner, Rouse Simmons, she sank in this at each wreck, to which blocks and The researchers also looked for area carrying Christmas trees in rods of various materials were evidence that zebra mussels are 1913. attached. The materials included hard enhancing reduction reactions, which wood (white oak), soft wood (white produce faster corrosion than oxida- The sonar traces a flat sand pine), wrought iron recovered from tion reactions. They found only slight bottom then a black bump stitch- Lake Champlain, hot-rolled steel and evidence of reduction reactions. es across the paper as a object polyvinyl chloride (PVC), a standard However, they suspect these reactions rises off the bottom … the tell tale sign of a wreck. A grappling continued on page 4 hook, goes over the side and in a short time the boat is anchored. The divers suit up and follow line to the three masted schooner below. Hand over hand down the line and shortly they are on the deck and in the few minute of bottom time they methodically go A diver inspects a ship- wreck part wrapped in about the business of remove tarp to deprive zebra pulleys and picking up a few mussels of nutrients. other artifacts in the galley. Time Photo courtesy of is short, they head back to the Canadian Conservation surface with the “ prizes”. A few Institute continued on page 8 2 Wisconsin’s Underwater Heritage June 2002 Wisconsin Underwater Archeology Association Spring Meeting The spring meeting of the association field work for this coming season is research into the legends of the was held on Saturday, May 11, 2002, up in the air. Poverty Island treasure and the Rock at the Door County Maritime Museum Work is continuing on the Lake pyramids. in Sturgeon Bay. Maritime Trails. This includes applica- Cathy Green reported that a new The meeting followed a tour of the tions for buoying six historical ship- WUAA brochure is being completed. Palmer Johnson and Bay Shipbuilding wrecks, working on a poster of the The fall meeting will be held facilities in Sturgeon Bay. Fleetwing wreck to be posted on Saturday October 12, 2002 in President Russell Green called the shore close to the wreck site and Madison with either a tour of the meeting to order. The treasurer, Tom nomination of a twelve stone ships Historical Society archives or the con- Villand reported a balance of $3850. for historical preservation. servation laboratory. The workshop at Superior on Tom Villand needs help in November 10, 2001 earned $536. researching the dam on the Yahara Our thanks go to Mrs. Pat Labadie for River by Madison. preparing the meal. The final mapping of the Christina Russell Green reported that due to Nielson wreck could be completed by the State of Wisconsin budget situa- the association this summer. tion, most of the Historical Society’s Dick Boyd reported on his Wisconsin’s provides support to mem- President Activities Coordinator Underwater bers’ research and publi- Russ Green Cathy Klecker cation projects. Annual Madison, 608-271-8172 Marshall, 608-655-3769 Heritage is pub- membership dues are $15. lished quarterly by the Vice-President Website Manager For membership informa- Wisconsin Underwater Hank Whipple Colin Zylka tion, contact the secretary Archeology Association, a Madison, 608-245-1222 Waukesha, 262-524-0145 or write to the address nonprofit association of Secretary Directors below. individuals and organiza- Russel Leitz Richard Boyd tions interested in study- Send correspondence to: Oshkosh, 920-231-9082 Delafield, 414-464-2092 ing and preserving the WUAA Treasurer Robert Korth underwater cultural PO Box 6081 Tom Villand Gresham, 715-787-4444 Madison, WI 53716 resources and historical Madison, 608-221-1996 Janet Defnet sites of Wisconsin. email: [email protected] Newsletter Editor Mukwonago, 414-363- In addition to publishing website: Danny Aerts 9874 www.mailbag.com/users/ this newsletter, the Middleton, 608-821-0048 Association also holds wuaa/ Jeff Gray semiannual meetings and Madison, 608-271-1382 June 2002 Wisconsin’s Underwater Heritage 3 New WUAA Shirts Just in time for summer, new WUAA shirts are now available. Tastefully designed, with the multi-colored WUAA logo on the front breast pock- et area, the shirts come in a variety of styles and sizes. There are white short-sleeved t-shirts and navy long- sleeved t-shirts from medium to XXLarge. The short-sleeved shirts are only $8.00, while the long- sleeved shirts are a mere $12.00. Support WUAA, while enhancing your wardrobe. Look for them at the next WUAA event. For t-shirt orders or information call Cathy Green at 608-271-8172, Part of the steamship Mueller is on display at the Leathem & Smith Quarry. email her at [email protected] Photo by Tom Villand or send a check with your order to: Cathy Green WUAA T-Shirts P.O. Box 6081 Madison, WI 53716 WUAA member takes a break during the shipyard tour in Sturgeon Bay. Be sure to include your current Photo by Tom Villand address, so we can send them to you. Order early to ensure your size is available. Jeff Gray Leaving WHS Jeff Gray, the state underwater arche- ologist, will be leaving the Wisconsin Historical Society. In July, he will take over as director of NOAA's Thunder Bay Marine Sanctuary in Michigan. Jeff was a past president of the Wisconsin Underwater Archeology Association and we wish him well at his new position. 4 Wisconsin’s Underwater Heritage June 2002 Zebra Mussels on Shipwrecks continued from page 1 n the March issue of Underwater Georgian Bay and in Deadman Bay, worked on the project. "If you remove Heritage, we discussed some basic Lake Ontario (near Kingston). them from corroded metal surfaces, Ibiology of zebra mussels and their Physical removal methods. For the you do actually pull away the corro- invasion into the Great Lakes. Here physical tests, they used gloved sion on the surface, which can induce we’ll focus on issues of more direct hands, surgical scalpels, dive knives, accelerated active corrosion on that importance to divers and underwater garden tools like trowels and hoes, surface again," Binnie said. archeologists: Can zebra mussels be several types of high-pressure water The study found the same thing cleared from shipwrecks without jets and various kinds of combs to lift with wood: pulling zebra mussels off damaging the wreck itself or the the mussel shell and byssus (the wood surfaces, particularly if they are aquatic environment? Do zebra mus- group of threads that attaches a mus- highly deteriorated, can tear off large sels cause long-term harm to ship- sel to a surface) off the shipwreck. chunks of wood with the mussels. wrecks? What other consequences are Divers attempted to apply these In general, the study concluded there when the prolific mollusks com- tools to the byssi or shells only, not that physical removal of zebra mussels pletely encrust shipwrecks? It appears directly to the wreck surface. Despite causes too much damage to wrecks to that only three studies have these efforts, the studies showed that be used on a regular basis. "We defi- addressed these questions. We’ll most tools damaged the surface of the nitely are telling people, ‘don’t scrape briefly review each of them. wreck. Divers found it difficult or off zebra mussels,’" Binnie said. Canadian government studies impossible to avoid scraping the Chemical removal methods. The In 1995, Parks Canada and the wreck surface because it was often study also looked at the possibility of Ontario Ministry of Citizenship, obscured by the mussels and the using various chemical compounds to Culture and Recreation began a multi- attachment mat. kill mussels on shipwrecks. The proj- year study on the impacts of zebra All the trials using high-pressure ect team recognized from the outset mussels on submerged archeological water jets resulted in damage to wood that chemical control of zebra mus- resources and on the effects of vari- or corroded surfaces.