Daily Iowan: UI, Navy Team Up to Test Seaworthiness of Ships

Friday, December 3, 2010

A sleek black naval vessel rocked against increasingly strong waves. Maneuvering through choppy water, the craft turned slowly and hastened back to shore.

But the ship was only about 10 feet long — and it was being buffeted by 1-foot waves in the University of Iowa's new $4.9 million wave basin.

The massive 20-by-40-meter pool — emblazoned with the world's largest Tigerhawk logo — is the first of its kind in the world. It is used to measure the seaworthiness of naval craft. The U.S. Office of Naval Research contributed $3 million to the project.

"This is a world first in terms of ship-hydrodynamics basins," said Larry Weber, the director of Iowa Institute of Hydraulic Research-Hydroscience and Engineering. "It allows us to do free model tests, so the ships we test here are remotely controlled and will navigate around in normal motions that a naval surface destroyer would do."

The new facility allows researchers unprecedented control in how they can create different conditions for ships and measure the results.

The ship models are shrunken down 50 times smaller than their real-life counterparts, so the 1-foot waves simulate 50-foot swells. They are remotely controlled to perform naval maneuvers such as zigzags, turning circles, and spirals. A bright gold 8-ton crane follows the craft from above the pool, allowing for minutely specific measurements of wave trajectories.

The tests are meant to measure a ship's ability to move through rough or calm waters without capsizing using certain computer codes, said Frederick Stern, a UI professor of mechanical and industrial engineering.

And these tests can save lives.

"If you are out in heavy seas, the smaller ships get tossed around a lot," said Randy Miller, a Navy veteran who was stationed on an aircraft carrier and served from 1973-75. "I have heard of people having to tie themselves down during a really bad one."

The facility, located in the University of Iowa Research Park, was finished in August, and for the past few months, it has undergone calibration tests. While the stability testing will soon begin, Weber said the data gathered from experiments can also be used to calculate a ship's detectability in the water.

The model being tested at Thursday's demonstration was a $55,000 tumblehome hull ship, whose design incorporates much of the Stealth bomber's shape, which the Navy hopes will make it less detectable to sonar and radar, Weber said.

Masaaki Sano, a postdoctoral UI student from Japan, waded into the light blue water, guiding the model out into the blue with a remote control.

"I think it is fantastic; I am very happy to work here," said Sano, who can control everything from the path of the craft to the frequency, velocity, and strength of the waves it encounters. "The size of the basin is not so large, but we can do many tests here."

Adam Connell, who spent five years in the Navy, said he has seen 30-foot swells while on frigate ships — some of the smallest in the Navy. The researchers' work could be extremely valuable, he said.

"[It's] definitely very cool for that new test facility, because you do not want to build $1 billion warships and not be able to use them to their full capacity," he said.