Frequently Asked Questions

What is the purpose of the Lake Guardian?
The mission of the R/V Lake Guardian is to collect data about the physical, chemical, and biological conditions of the Great Lakes using samples of water, air, sediments, and aquatic organisms like plankton. Most of the research is focused on studying the lower food web of the lakes. The vessel conducts a month-long survey in the spring and summer each year, operating on all five Great Lakes for monitoring and surveillance. Guest researchers are invited to make use of the ship’s facilities for their individual projects as space permits. For more information, go to Ship Background

Who runs the Lake Guardian?
The Lake Guardian is a U.S. Environmental Protection Agency research vessel operated by the Chicago-based U.S. EPA Great Lakes National Program Office (GLNPO). All of the Lake Guardian crew members are contracted out by the EPA from a company called Cetacean Marine, which is based out of Florida.

What are the size and capacities of the boat?
The Lake Guardian is 180 feet in length and has a depth of 14 feet, displacing 850 tons. The fuel capacity is 79,000 gallons, the ballast water capacity is 76,500 gallons, and potable water capacity is 29,000 gallons. Berthing capacity is 42 passengers. For more information, check out Ship Specifications

How many people are there on the ship?
The Lake Guardian has a permanent crew of up to 15 people, however the berthing capacity of the Lake Guardian is 42 passengers. The number of additional passengers varies by cruise, depending upon how many EPA and visiting scientists are involved with a particular project.

Who makes up the crew?
The Lake Guardian has up to 15 permanent crewmembers. The crew is made up of a captain, first and second mates, marine technicians, ordinary and able-bodied seamen, engineers, galley staff and steward. While out on the water the ship is manned 24 hours, with crew members working shifts of 6 hours on and 12 hours off.

Where did the ship come from?
The Lake Guardian was constructed in 1981 and operated in the Gulf of Mexico as a supply vessel for offshore oil rigs until 1988.  It was then purchased by the U.S. Environmental Protection Agency and converted into what is now the EPA’s largest research and monitoring vessel on the Great Lakes.

How long has the ship been operating?
The Lake Guardian has been operating as a research vessel on the Great Lakes since 1990. Prior to its conversion it had been in operation in the Gulf of Mexico from 1981.

How much fresh water can be stored on board?
The Lake Guardian has a potable water capacity of 29,000 gallons.

Where does the Lake Guardian get fuel?
The ship fuels up in its homeport in Milwaukee, WI. Refueling can take an entire day, as the Lake Guardian can hold up to six tanker trucks worth of fuel.

How long can the ship go before it needs to refuel?
This depends on how much traveling the ship does during a survey (i.e. is it primarily anchored while collecting samples or in transit from one site to another for long periods of time?). The ship can store 79,000 gallons of fuel, so typically the fuel is not the limiting factor in the length of a cruise. The ship’s endurance is 2-3 weeks, so the ship refuels as needed when in port to pick up other supplies and change crew and/or scientists. 

Where does the ship go?
The Lake Guardian travels throughout all five Great Lakes (Superior, Michigan, Huron, Erie and Ontario) and their connecting channels.

How do crewmembers receive mail?
There is a marine post office in Detroit, the only one in the country! A small boat named the J. W. Westcott II delivers mail directly to the ship (the transfer takes place by the Ambassador Bridge).  The “postal worker” simply hands the mailbag and boxes of supplies across to the Lake Guardian crew and the crew hands him back a bag of outgoing mail. Mail can be sent to any ship that passes through Detroit by addressing it to “ship name, Marine Post Office, Detroit, MI”.  For more information, check out

How fast can this ship go?
The Lake Guardian has 2 engines, each with 1200 horsepower, and has a cruising speed of 10.8 knots. That is equivalent to 12.4 miles per hour on land.

The R/V Lake Guardian sails on behalf of the USEPA Great Lakes National Program Office, gathering environmental data to gauge the health of Great Lakes.

What's Happening?

The 2018 sampling season has begun! See the full schedule here »

Read about the Lake Guardian and Captain Mallard in the Illinois-Indiana Sea Grant newsroom »

Check out a social media recap of the 2016 Summer Survey »

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