Characterization of the Movement of a Sinker During Deployment.
Abstract
Studies were made to determine the horizontal offset incurred by typical Coast Guard sinkers (which are used to moor floating aids to navigation) as they fall from the surface to the bottom of the sea. A series of experiments was conducted in which sinkers were dropped in water and their offsets at the bottom recorded. Included were sinker drops in highly controlled conditions, some of which were recorded on film; and drops from a barge in more typical field conditions. The effects of the following parameters were considered: sinker size (up to 8500 lbs.), depth of water (up to 102 ft.), height of sinker above water at time of release (up to 6 ft.), current (up to 4 knots), location of center of gravity with respect to the centroid of the sinker, initial tilt of the sinker, and the presence or absence of chain attached. It is found that offsets generally increase with sinker size and water depth, to a maximum of about 12 feet in still water. The height above water, initial tilt, and presence or absence of chain have small or negligible effects. Some sinkers are found to exhibit a bias in offsets in one direction. The trajectory of the sinker as it falls, and the effect of current on offsets, are discussed from a theoretical point of view and experimental data are presented. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1977
- Accession Number
- ADA080400
Entities
People
- J. W. Cutler Jr.
- R. A. Marcolini
- R. T. Walker
- W. E. Colburn Jr.
Organizations
- United States Coast Guard Research & Development Center