The agency had recently developed a high-resolution side-scan sonar called SAR and agreed to send a research vessel, Le Suroît, to survey the sea bed in the area where Titanic was believed to lie. The idea was for the French to use the sonar to find likely targets, and then for the Americans to use Argo to check out the targets and hopefully confirm whether they were in fact the wreck.[32] The French team spent five weeks, from 5 July to 12 August 1985, "mowing the lawn" – sailing back and forth across the 150-square-nautical-mile (510-square-kilometre) target area to scan the sea bed in a series of stripes. However, they found nothing, though it turned out that they had passed within a few hundred yards of Titanic in their first run.[33]