“Third grade students crowd in front of the Mary L’s wheelhouse to watch the ship pull out of the Langley Small Boat Harbor.Matt Johnson / staff photosKorey Roberts had never seen an underwater camera before this week.The South Whidbey third grader held the softball-sized camera in both hands while he and seven of his classmates waited Wednesday morning for a ride aboard a floating classroom called the Mary L. To test the camera, Roberts put the device to his eye while his friends watched a video display behind him. All they saw was a big eye.Hey, you can see it blinking, said one of his classmates.This was the children’s first learning experience aboard the Mary L., an American Institute of Marine Studies (AIMS) tugboat captained by former Langley Middle School teacher Chris Burt. During this week and the next two, third, fifth, seventh, and eighth graders are taking turns riding aboard the Mary L., learning about everything from undersea life to island ecology. The seventh graders will travel to Hope Island aboard the tug for three days, while the eighth graders will take a five-day trip to the San Juan Islands. The younger children got only a taste of sea travel, spending just a few hours on the Mary L’s deck to learn about life at sea.Jackie Gelston, a third-grade teacher at South Whidbey Intermediate School, helped bring the Mary L. to South Whidbey. Even though the Mary L. is an expensive boat to operate — it consumes between 10 and 80 gallons of fuel every hour — the two weeks of educational programs aboard the 50-year-old tug will cost South Whidbey Schools nothing. AIMS sends the boat around the Puget Sound area for teaching programs free of charge.Gelston said her class will use their experience aboard the boat to tie into a science unit about space exploration.This experience gives them something to hang more abstract ideas on, she said. The ties between space and the sea are closer than most people would think. Aboard ship, the children studied an environment that is largely hostile to humans, unless they have the right equipment to explore it. To look at the bottom of Langley marina, where the Mary L. was docked, the students used the underwater camera, which was controlled from the deck by Mary L’s engineer Adrian Brown. What they saw on the camera’s video screen was not dissimilar from looking at the surface of an exotic planet. There was dust, strange debris and fingerlings and starfish that could have just as easily been alien creatures.Cool! A fish! came the cry from several students.That’s an octopus, said one.No, it’s a starfish, said another.A few minutes later, the tugboat plowed into the waters and heavy fog of Saratoga Passage. With Capt. Burt at the helm, engineer Brown took the opportunity to show some of the children how to navigate under less than ideal conditions. He showed them sailing charts, a pocket-sized Global Positioning Satellite receiver, and several optical devices. Jackson Engstrom spent much of the lesson looking through a Russian-made night vision scope and asking questions about how certain objects look at night. Green, was Brown’s simple answer.Amidships, Gelston helped her students look through several microscopes at plankton Brown had collected with a finely-woven net minutes earlier. Working in groups of three or four, the students identified several types of phytoplankton (plants) and zooplankton (animals) that make up the greenish tinge in Puget Sound waters.Above their heads in the wheelhouse, a third group listened to Chris Burt as he explained how he pilots the Mary L. To demonstrate the boat’s workings, Burt throttled up the engines every few minutes, thrilling his group, but making plankton studies difficult among the budding microbiologists below.By lunchtime, however, the children needed something more than tiny beasties and the science of seamanship to hold their attention. While they ate their sandwiches and potato chips, Adrian Brown gave Burt the cue to pull out all the stops.They’re falling asleep down here! he yelled up to the wheelhouse.With that, Burt put all of the Mary L’s 1,000 horsepower to the props and set the boat leaping up to 15 knots. All the children put their lunches aside to crowd aft and laugh and point at the 8-foot-high wake the Mary L. boiled up behind her.Thirty minutes later, the boat was back in dock. The children were not ready to go back to their classroom. Cayla Calderwood said the Mary L. was an experience like no other she’d ever had.It felt really as if we were somewhere where, like, nobody had ever experienced how fun it was, Calderwood said.Chris Burt said the Mary L. has come to South Whidbey before to work with Jay Freundlich’s eighth-grade students. This was the first year the younger students spent time aboard the boat. “