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Title: River tow behavior in waterways. Report 1, Exxon Test Program
Authors: R. M. Schulz Associates
Schulz, Roger M.
Keywords: Exxon test program
Tows and towing
Inland navigation
Mississippi River
Publisher: Hydraulics Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: Technical report (U.S. Army Engineer Waterways Experiment Station) ; H-78-17 rept. 1.
Description: Technical Report
Abstract: This is the final report by R. M. Schulz Associates (RMSA) to the Corps of Engineers (COE) on the study to obtain and analyze river tow behavior data. This report describes the first full-scale tow test program conducted in this country in which second-by-second records of tow position, attitude, rudder, power, and river environment parameters are obtained and analyzed. The study demonstrates the feasibility of using off-the-shelf position fixing and rudder angle recording equipment to measure the dynamic behavior of river tows. Study results, based on analysis of over 6500 second-by-second digital records of 42 test, tow, and waterway parameters, are summarized below. (1.) Turns at half-power through 90° of a 3250-foot radius river bend with a current of 2.2 feet per second show that: (a) average downstream drift angles are double upstream drift angles, (b) maximum drift angles are greater than 20°, and (c) speed loss is almost 30 percent downstream and 13 percent upstream. (2.) Zig-zag maneuvers at full power using about 10° of rudder show that: (a) maximum drift angles and angular velocities are greater upriver than downriver, and (b) speed loss is at least 7 percent of initial speed. (3.) With the tow moving at full power downriver, the minimum distance required to perform a "crash" stop is at least two tow lengths. (4.) Speeds will fluctuate from 15 to 37 percent during constant power, straight course operation due to steering, current, and river bank and bottom effects. (5.) A 15 percent port and starboard power imbalance on a twin screw towboat requires about 2° of rudder angle to compensate. (6.) Rudder angle measurements indicate that centerline stops for the steering rudders will improve underway efficiency. (7.) Computerized tow performance data obtained from this study completely describe tow motions in the horizontal plane such that: (a) yaw, sway, and surge parameters may be used in traditional mathematical models of tow dynamics; (b) waterway and tow parameter interactions may be used to identify waterway design anomalies; and (c) pilot steering responses to observed accelerations may be used to evaluate self-propelled model tests. NOTE: This file is large. Allow your browser several minutes to download the file.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Technical Report

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