Sitting Pretty

During dock trials in San Diego Harbor recently, the rebuilt and upgraded submersible Alvin underwent an incline test while attached to the stern of its support ship, R/V Atlantis. The test was designed to measure the sub’s stability in the water and to calculate its righting moment—the force that tends to restore a leaning, or heeling, ship to upright. From the test, the sub was found to be even more stable than the previous design.(Photo by Lisa Smith, Woods Hole Oceanographic Institution)