sealPurdue News

August 5, 2002

Puff of pneumatic air lifts boats for boater safety

WEST LAFAYETTE, Ind. – Lifting a boat has never been easier – or safer.

Matt Martin, a former Purdue University agricultural and biological engineering student, and Gary Krutz, professor of agricultural and biological engineering, have developed a pneumatic boatlift that raises boats out of the water without the use of electric motors.

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Krutz says the device could replace electric motors currently used by boaters, and is much easier than hand-cranking a boat out of the water.

"From a safety standpoint it makes sense," Krutz says. "Having an electrical hot wire on a boat dock means you could have a problem."

Krutz says maintaining electrical power at a private dock or small marina can be troublesome.

"Near the water you have constant moisture, and when it comes to maintaining an electrical system it will drive you nuts," he says. "Everything gets moldy and green after two years. Then one winter some varmint chews through the insulation during the winter, and when you turn it on in the spring you blow your fuse or you get a very lively area."

Martin says he surveyed local marinas to see if such a device would be welcome and found it was. "They were all for a different method to raise boats," he says. "They said that running conduit along the docks is always a problem."

Martin constructed the pneumatic boatlift using a standard air compressor, such as those one might find in a local hardware store. "We wanted to keep it simple," he says. "A bigger compressor is very expensive."

The pneumatic boatlift was designed to work to standard friction drive boatlifts. It would only replace the electric motor, not the entire device.

The airlift is powerful enough to raise an 18-foot boat, and it also would work for a 21-foot boat or a pontoon boat, Krutz says. "It's not designed to raise those 35-footers, but those only get lifted out of the water once a year," he says.

Although the compressor itself uses electricity, it can be placed away from the dock. Martin and Krutz designed the system to have the compressor 60 feet from the dock, but in tests they have placed the compressor as far as 250 feet away from the dock and run air hose to the dock to power the lift.

"There was very little loss of power," Krutz says. "It was less of a power loss than if you had run an electrical line down to the dock."

Krutz says he expects an air-powered boatlift would cost about the same as current electrical boatlifts.

"Electrical boatlifts cost around $600, and we built this prototype for $700, so I don't think that if one were produced on a commercial scale that it would cost any more than what is on the market now," he says.

Martin says having compressed air at the boat dock has other advantages, too.

"Many boaters like to pull tubes behind their boats, and this makes it easy to inflate the tubes at the dock," he says. "You can also attach a blowgun to the air line and clean out the boat at the end of the day."

Martin developed the pneumatic boatlift as his final senior engineering project for Purdue Course ABE 485: Agricultural Equipment Design, which Krutz teaches.

Despite all of the noodling required to engineer the device, Martin says that wasn't the hardest part of the project. The most important lesson he learned while working in a pseudo-industrial environment was that you have to focus on the human resources.

"The hardest part was dealing with people. The most difficult part of the project was getting things delivered in the time allotted," Martin says. "I learned that dealing with people is the one of the most critical parts of a project, just like in industry."

Since graduating in May with a degree in agricultural and biological engineering, with an emphasis in machine systems, Martin, who is originally from Kouts, Ind., has worked for Turblex Inc. of Springfield, Mo., as a engineering project manager working on large industrial air compressors.

"The experience of my senior design project has helped tremendously in this position," he says. "You get a real-world flavor from Professor Krutz's classes that is very valuable."

Writer: Steve Tally, (765) 494-9809;

Sources: Gary Krutz, (765) 494-1179;

Matt Martin, (417) 864-5599;

Ag Communications: (765) 494-2722; Beth Forbes,;

Purdue professor of agricultural and biological engineering Gary Krutz (left) and graduate student Louis Cassens demonstrate a pneumatic boat lift developed in the agricultural equipment design course. The airlift is powerful enough to raise and lower a 21-foot boat and could be manufactured for about the same cost as an electrically powered lift. (Purdue University photo by Tom Campbell)

A publication-quality photograph is available at

Purdue News Service: (765) 494-2096;

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