Accession Number:

ADA609540

Title:

Deploying and Recovering Marine Instruments With a Helicopter

Descriptive Note:

Technical note

Corporate Author:

ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB

Report Date:

2000-09-01

Pagination or Media Count:

9.0

Abstract:

This Coastal Engineering Technical Note CETN describes the method and hardware for deploying and recovering instruments in coastal waters by means of a Chinook helicopter CH-47. To fulfill its mission of designing, building, and maintaining coastal projects, the U.S. Army Corps of Engineers USACE relies on accurate data on the dynamic ocean. Measurements of waves, currents, and other parameters enter the decision process and lead to more effective designs. Sophisticated sensors may be lowered into the water for one minute or left in place for years, and deployment techniques must be adapted to a variety of environments. The traditional platform for this work is a boat or barge, an approach that is appropriate if sea conditions are relatively mild. However, there are times and places where conditions can render this form of deployment unsafe, logistically difficult, or economically unfeasible. Installation of instruments in the surf zone and in large inlets is particularly challenging, even under calmer wave conditions. Amphibious vessels have proven useful in many situations, but for some locations, such as the Northern Pacific coast of the United States, dangerously energetic surf is normal. It is in these situations that the Corps and others have accessed the capabilities of helicopters to accomplish the data-collection mission. Previous uses of helicopters for ocean measurements include surveying Graig and Team 1985, deploying permanent floating and bottom-mounted gauges, laying cables through the surf zone McGehee and Welp 1994, and taking spot measurements of the current Pollock 1995. In each case, the over-water hover time was relatively short, on the order of a few minutes. Although many measurements can be obtained with a short-duration insertion, a wave measurement requires a sample length of about 20 to 40 minutes during which the instrument must remain stationary on the sea floor.

Subject Categories:

  • Helicopters
  • Physical and Dynamic Oceanography
  • Test Facilities, Equipment and Methods

Distribution Statement:

APPROVED FOR PUBLIC RELEASE