Lake Minnetonka Nautical Archaeology Project: Anomaly Assessment and ROV Study

MHM short and intermediate term goals for this project were met in any measurable way. MHM's primary goals for the Lake Minnetonka Nautical Archaeology: Anomaly Assessment and ROV Study (LMNA-AA-ROV) Project, a Phase 1 archaeological reconnaissance survey, was to: 1. Examine specific wrecks and anomalies recognized through a sonar survey and determine their significance as submerged cultural resources; and 2. Determine the validity of and the value of using a low-cost Remotely Operated (ROV) in the identification of unknown anomalies, particularly deeper targets. During the LMNA-AA-ROV Project, MHM examined 38 anomalies assigned these numbers: were A84, A76, A88, A90, A113, A117, A125.3, A129.6, A256, A456, A465, A475, A544b, A579, A581, A590, A614, A623, A625, A630, A646, A648, A649, A653, A650, A651, A654, A670, A671, A673, A674, A675, A676, A689, A690, A691, A692, and A694. MHM also dove on 2 known wrecks to answer archaeological questions: the Small Utility Wreck Site (Anomaly 601, now known as the Herter's Model Hudson Bay Wreck) and the Burned Fiberglass Wreck Site (Anomaly 600). MHM also revisited one previously known object, the Anchor, Metal, Glass, and Wood Site (Anomaly 599), to answer questions - it is now known as the Possible Buried Car Site. Using data accumulated from the fieldwork as a starting point, MHM conducted research to place newly recognized nautical archaeological sites and anomalies into their historical contexts. Minnesota Archaeological Site Forms were filed with the Office of the State Archaeologist (OSA) when appropriate: Fisherman's Friend Wreck 3 (Anomaly 676, 21-HE-499), Wooden Motor Boat Wreck 2 (21-HE-500), Hydroplane Wreck (Anomaly 651, 21-HE-501), Hydroplane Wreck 2 (Anomaly 691, 21-HE-502), Burned Fiberglass Wreck (Anomaly 599, 21-HE-504), and the (maritime site) Marine Launch Boiler Site (Anomaly 117, 21-HE-503). The other wrecks identified during the project are: Jet Stream Wreck (A84), Crestliner Admiral Wreck (A689), and the Forester Canoe Wreck (A694) - MHM and its volunteers confirmed the existence of 7 new wrecks. Initially, the proposed number of anomalies to be investigated were at a minimum - 32 unknown targets along with 2 known wrecks and 1 known object to answer questions about their nature. Therefore, MHM dove on 41 targets as opposed to the minimum number of 32 targets proposed a highly successful project. Seven more wreck sites were included in the on-going Lake Minnetonka sediment study; Bruce Koenen of the OSA suggested the study in 2013 in order to determine the rate of sediment build-up in different areas of the lake. This data is used to approximate the sinking dates of boats and other resources, using wrecks with known sinking dates for comparison. During the LMNA-AA-ROV project, in addition to the submerged resources described above, MHM also identified 5 new maritime sites/objects (1 boat hatch cover, 1 boat lift, 1 capsized barrel raft, a collection of 7 fish cribs, 1 anchor) and 3 other objects/sites (1 rubble pile, 2 barrels). Natural anomalies in include 5 tree stumps (all natural but dumped on the ice/in the lake on purpose), 5 rocks or rock piles, and 14 false targets that were unusual bottom contours or vegetation. MHM's 2nd objective for the LMNA-AA-ROV Project was to test the viability of using a low-cost ROV in deeper water to identify unknown targets in order to plan dives more efficiently and as a by-product, safely. MHM first tested the ROV in shallow water at a shoreline dock, and with practice, the ROV performed well. MHM then tested the ROV on a known relatively shallow (28 feet deep) wreck, testing out different rigs in order to more effectively pilot the robot underwater. The test was successful in that MHM took some photos of the wreck. The next test was on Anomaly 625 in 46 feet of water. MHM had problems navigating the ROV not only on the surface, but on the lake bottom. While the ROV has a depth sensor, the directional sensor is useless and the machine lost communication with the topside laptop several times, resulting in complete re-boots of the ROV and it had to be brought to the surface. Through many trials, MHM finally located Anomaly 625 a tree on the lake bottom. Therefore, while technically successful, in that MHM identified 2 objects on the lake bottom, the use of this generation of ROV is not helpful for MHM's goals and work because of its extreme limitations (see attached). The ROV had directional problems in 28 and 46 feet; the problems would only get exponentially worse in 80, 90, or 100+ feet of water - particularly since sunlight is lost around 70 feet deep, creating virtually a night diving situation. A more advanced - but relatively low-cost - ROV was supposed to be on the market in June 2017 but the manufacturers are behind in development, and it is not yet available. One of MHM''s volunteers has placed an order for one of the units, so MHM will test it in the future to determine its value to underwater archaeology. For now, the ROV tested is only good in shallow water with great visibility conditions MHM only deals with about 20% of the time, and SCUBA divers can perform the work better and faster than an ROV. After the completion of the LMNA-AA-ROV Project fieldwork in September 2017, there are now 66 wreck sites identified on the bottom of Lake Minnetonka (including a dugout canoe that was removed from the lake in 1934). Of these wrecks, 41 of them have 40 Minnesota archaeological site numbers; 2 wrecks are features of one site. Further, 4 other types of maritime sites have archaeological site numbers and there are 25 maritime sites or objects without numbers. Additionally, 27 'other' objects have been identified that do not have site numbers, including 8 vehicles that include a snowmobile, truck, and 6 cars. All the resources dove upon during the LMNA-AA-ROV Project were rudimentarily documented for future study. For those not provided numbers during the project, designations as nautical or maritime archaeological sites in the future is possible; data from this project will be used at that time. The goal of educating volunteer divers on proper search techniques was exceeded-the amount of data collected during the diving, the great attitudes of MHM's volunteers about the sites investigated, and the eagerness to investigate more anomalies to learn about them is rewarding. MHM's plan to educate the general public through social and professional media have also met with great success - including 2 archaeology fairs encompassing 3 days, 2 public speaking engagements and MHM's participation in a University of Minnesota Continuing Education class in September 2017. MHM's 'followers' on social media increased greatly due to the LMNA-AA-ROV Project. Followers have learned about the importance of keeping submerged cultural resources unspoiled and about the impressive maritime history of Minnesota that MHM is continually uncovering. An online dialog about the significance and rarity of Lake Minnetonka's and Minnesota's protected nautical, maritime, and underwater cultural resources is on-going and will continue. During the LMNA-AA-ROV Project, MHM met expectations and produced substantial and meaningful results from this project due to sound fieldwork planning, solid methodology employed during the fieldwork, the previous systematic methodology employed during the remote sensing surveys that provided good data, and the utilization of knowledge gained from MHM's other Lake Minnetonka Nautical Archaeology Projects. Further, while the ROV testing did not provide the desired results, MHM has proven that at this time, it is not appropriate to use for serious underwater archaeological studies; it is more of a fun toy for people to play with in shallow water. Investing in more advanced remote sensing sonar equipment (MHM's unit was new and state-of-the-art in 2010, but technological advancements are many and they move quickly) is a better and a time-tested alternative for MHM - acquiring a new unit is a priority. Additionally, MHM's vetting of volunteer divers choosing only ethical, responsible people who understand our Mission to locate, document, preserve, and conserve Minnesota's finite submerged cultural resources within a not-for-profit paradigm led to a productive and honest working environment in the field. Fundamentally, MHM conducted sound nautical and maritime archaeology, strong maritime historical research that produced trustworthy data for analysis and future use, and we chose a group of trustworthy volunteers to assist us with the fulfillment of this project's goals.