A Quasi-Static Design Model for Synthetic Marine Towlines.
Abstract
A model of the elongation characteristics of a double braid nylon rope is presented as an aid to sizing a marine towline. The material and structural elongation properties are combined and modeled as being the sum of a non-elastic permanent elongation and a load dependent elastic elongation. The loading range of practical interest is examined and a design factor of safety, with both an upper and lower bound, is established. The lower bound is incorporated to limit relative movement between structural elements in an attempt to control internal abrasion. The upper bound is imposed to stay within the safe working load and total elongation limits of the rope. The governing equations for the towline are then solved within these constraints for a typical submarine towing system to provide a towline capable of sustaining the hydrodynamic loads due to the resistances of the submarine and the towline. It is shown that the resistance of a typical towline may be of the same order of magnitude as the resistance of the towed vessel and cannot be neglected. The solution results in a recommended towline diameter and breaking strength which is then examined under possible loading conditions other than those selected for the initial design.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1984
- Accession Number
- ADA144814
Entities
People
- W. N. Proctor
Organizations
- Massachusetts Institute of Technology