Something fishy

Montana wildlife agency is tankful for transport designed by Flathead High School students

The Daily Inter Lake

Five Flathead High School seniors made their mark this spring on the future of fish populations in Montana's lakes and rivers.

Neil DeZort and Jerry Nahring, the team leaders, worked alongside Chris Brim, Trevor Troutwein and Jarred Flores to design a one-of-a-kind fish transport tank for Montana Fish, Wildlife and Parks as a final project in their Drafting 4 class taught by Dennis Latimer.

"I think the greatest thing for all of us was to see it actually come to be," Nahring said of the computer-aided design process used to create the tank envisioned by Grant Grisak, fisheries biologist in the agency's Kalispell office. "It was kind of a collective brainstorming."

"It gave us an idea of what it's like to work with a client," DeZort added.

Grisak said the agency will dangle the cone-shaped aluminum tank beneath its helicopters to stock large fish in remote waters.

Larger fish not only mean an immediate fishery for the backwater angler, but much-sooner spawning in the wild waters to replenish their populations.

Technology has advanced since the agency started aerial stocking in the 1930s by flying over remote lakes and dumping 1 1/2-inch fish from a cream can. Fixed-wing craft did fine over time, Grisak said, but the agency was limited to stocking only small fish.

Even today, he and his colleagues prop a tank full of tiny 1 1/2-inch fish in the backseat of a helicopter to stock otherwise inaccessible waters.

"Our charter is to provide diversity and abundance of angling opportunities for the public," Grisak said. "This lets us give more opportunities to stock. We had larger hatchery fish, so we were limited to where we could put them" - into lakes or reservoirs accessible by truck.

Not only will the agency now be able to take larger, 2- to 3-year-old hatchery fish into remote areas, but they also will be able to fortify genetics by angling in the wild to augment the hatchery brood stock.

"We can take this [tank] back to a remote area, set it down and use whatever means to fill it up for a couple days. Then somebody can come back and fly it out," Grisak said. "It's a good idea to add some wild genetics to the fish stock every now and then."

Its design not only gives the fish plenty of room to remain in there for that time, but the tank is sturdy enough to withstand the elements.

Grisak got the ball rolling earlier this year when he approached Latimer with the idea for the school to partner with Fish, Wildlife and Parks.

Latimer thought it would be a great learning experience for his five senior drafting students.

"I had the idea of what I wanted," Grisak said. He used concepts from a fire bucket, other fish tanks and a concrete bucket used on cranes for dam building.

"I took those three designs and incorporated them into one design. I worked on it for probably three or four months. When I had the concepts together and had sketches, I took it to the high school. We needed some kind of plan, something clean for a machinist to work off of," he said.

For Grisak, who had built outhouses and picnic tables for local parks officials while he was a student in Great Falls, it was a natural partnership.

"I thought they could use it as a practical experience," he said. "And obviously there's a cost savings for us. We didn't have to go to an engineering firm. We looked at [the students' designs], made a few modifications, then took it to a machinist."

Grisak said the final tab was half of what a commercial bucket would have cost, and instead of having to make concessions, "we got exactly what we wanted."

The students worked with a trio of computer design programs - Pro-Engineer, donated to the school by SemiTool; Solid Works and Auto CAD.

They all knew the software pretty well, they said. DeZort, Nahring and Brim each went at the design challenge with a different software program, while Troutwein and Flores researched gauges of metal, other tank designs and related issues to modify what the first three designed.

It took at least a month to work it all out, the seniors said.

"It was satisfying to be able to make the changes," Troutwein said.

The end product is a 99-pound aluminum tank, a tapered cone fitted into a squared release channel with a trap door to release fish. It's supported by external stabilizing bars and internal crossbars at the top. An aluminum lid provides uniform darkness so fish will swim throughout the 58 gallons of water instead of pushing to the bottom. With a capacity for as many as 400 8-inch fish, its 585-pound filled weight is easy for a helicopter to hoist.

"The door design was the big thing here," Grisak said. "I'm real happy with it."

It was essential to transition from the cone's circular cross-section to the squared-off release door to deliver the fish, Grisak knew, so he checked with the fabricators and machinists at Metal Works of Montana in Missoula. They said it was possible.

"My challenge to the kids was to make this go from 10-inch round to 10-inch square," he said.

DeZort said the team came up with a cam lever mechanism to hold the door closed on one side, and a spring hinge which opens with the rush of water when the lever is released then angles back near the closed position when empty. It prevents door damage when the tank is set down.

They also added a 100-percent efficient oxygen tank to diffuse microbubbles from the atmosphere into the tank. Grisak said it can deliver 116 hours of continuous service - important, for example, when the agency needs to deliver wild fish from 12 Flathead streams down to the state hatchery in Anaconda.

A final modification was the addition of the aluminum lid, accommodating the instinct of fish in the wild to go for cover.

Grisak is delighted with the students' work on the tank, which he said will be used statewide.

"This was made in the Kalispell region, but since we have the tool it will be used where the need is," Grisak said.

"Had this not been built, the alternative would be to stock only small fish, or use horses or backpacking to get small fish in there," he said. But now, by using the cooperatively built and designed transport tank, "within an hour, you create a fishery."

Reporter Nancy Kimball can be reached at 758-4483 or by e-mail at nkimball@dailyinterlake.com.