Inclining Tests and Laser Measurement

Apr 21, 2008 12:00 AM

Highslide js

Highslide js

JMS has been active conducting stability tests for a wide variety of ship types. Stability tests have been conducted aboard tugs, sailing vessels, research vessels, and amphibious passenger vessels this past year. In many cases the vessels are older and undergoing major modification.

K-SEA Transportation
      77ft tugboat Davis Sea
      94ft tugboat Houma

Great Lake Science Center
      65ft research vessel Kaho

Yankee Sailing
      43ft sailing vessel Yankee

Boston Duck Tours
      31ft amphibious DUKW tour boat

Allied Transportation
      120ft tug Falcon

These older vessels often do not have vessel plans to work from. To create a computer model of the hull, JMS has been using laser measurement with much success. It is far more accurate and efficient than manually measuring complex hulls. The laser measures up to 50,000 data points and imports them into a 3D modeling and analysis program. A surface is fit through the points to create the shape of the hull.

Another technology JMS has been employing is the use of a clinometer instead of the traditional pendulum to measure heel angles during inclining tests. The clinometer measures roll and pitch angles relative to the vertical gravity vector more accurately than the traditional pendulum and batten arrangement. The sensing element is a glass vial half-filled with a conductive liquid. When the sensor is level, fluid covers five internal electrodes to equal depth. When the sensor tilts, the depth of fluid on each electrode changes, altering the electrical resistance between matched pairs of electrodes.
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