Narrative of a Five Years Expedition Against the Revolted Negroes of Surinam. JOHN GABRIEL STEDMAN. Edited, and with an Introduction and Notes, by Richard Price and Sally Price. Baltimore: The Johns Hopkins University Press, 1988. 808 pp. $95.00 (cloth). ISBN 0–8018–3416–3.

Narrative of a Five Years Expedition Against the Revolted Negroes of Surinam

At the nautical bottom approach, part of the fluid mud layers can be included in the available depth if they present favorable rheology. As it is difficult to perform in situ rheological profiles, the most adopted procedure is to correlate these properties with other easier measurable ones, typically density. One technique for assessing in situ density profiles is the use of a tuning fork density probe. Density is calculated through frequency and amplitude signals, based in a specific algorithm from the employed device. This method requires a calibration, using local sediment at several densities, as it is conditioned by the rheology of the mud. In order to link the rheological properties of the fluid mud to the response of the tuning fork, first, an algorithm for density calculation was proposed and compared to the standard equipment software. Then, mud samples from different regions in Brazil were employed and a single curve associating the densitometer amplitude signal and the yield stress of the samples was obtained. The proposed approach enables a quick rheological assessment without laboratory rheological tests. It simplifies the steps of the protocol for establishing the critical limit once applying the nautical bottom concept, and it can be replied to other ports and navigation channels.

Assessing rheological properties of fluid mud samples through tuning fork data

Internet of Things technology has been widely used in water traffic research. Many critical waterways in the world are becoming more crowded due to many factors in waterway environments, such as invisibility, variability, and uncertainty. Accurate water depth information is necessary to improve navigation safety. Water depth information of electronic charts cannot be updated in a timely way, while the actual water depth is unpredictable, and this factor threatens the safety of vessels in waterway environments. Based on the shore-based network, ship navigation data and other big data can be integrated to vessels navigation environments in real time. In this paper, we present a new scheme to quickly and accurately construct a vessel safety navigation depth reference map, which contains appropriate channel water depth information. This effective scheme is based on automated identification system (AIS) data and increases the travel safety through crowded waterways. AIS data include rich maritime traffic information. Both the static and the dynamic information about vessels through waterways can be extracted and processed from big real-time AIS data. Based on extensive actual experiments, we apply data mining techniques to extract the waterway depth information both draft-depth and vessel trajectories based on AIS data. The data are collected from vessels in both locations: 1) the Nantong port, in Jiangsu Province, China and 2) Meizhou Bay waterway, in Fujian Province, China. The Hermite interpolation scheme is used to patch the trajectories of vessels, and the BP neural network model is introduced to predict the maximum vessel draft. Clustering and data fusion methods are employed to construct a vessel safety navigation depth reference map according to the cluster area of vessel trajectories and draft information. The experimental results demonstrate that the vessel safety navigation depth reference map accurately reflects the current water depth profile of channels. This paper can provide accurate and timely channel water-depth information for the vessel navigation and the maritime supervision. The proposed scheme in this paper can also provide reference for trajectory data processing and mining.

Mining Channel Water Depth Information From IoT-Based Big Automated Identification System Data for Safe Waterway Navigation

Two-dimensional modeling of fine sediment transport with mixed sediment and consolidation: Application to the Gironde Estuary, France

This study addresses the dynamics and navigability of fluid mud by considering the implementation of a nautical-bottom approach using a combination of several measurement techniques. The Po...

Strategies for Measuring Fluid Mud Layers and Their Rheological Properties in Ports

The present state of navigation engineering knowledge concerning nautical depth in ports and waterways with fluid mud is summarized to examine the potential for successful application of the nautical depth concept in U.S. navigable waterways. Nautical depth defines a safe and effective channel bottom criterion in areas where fluid mud confounds conventional acoustic (echo sounder) surveying methods. Fluid mud is a high-concentration suspension that typically behaves as a non-Newtonian fluid. It occurs in ports and channels on all U.S. coastlines and accounts for a significant portion of the United States’ $1 billion dredging expense. Nautical depth has been adopted in multiple ports on three continents. Where nautical depth application is appropriate, it often reduces dredging frequency and dredged material volume and can provide water quality benefits. Multiple experiments and field experience have shown that vessels can safely transit areas with fluid mud below the keel. The United States’ adopt...

T. L. Welp

Papers

Nautical Depth for U.S. Navigable Waterways: A Review