Stress monitoring tool improves stability, integrity of floating structtures

Keeping track of cargo, whether bulk or containerized shipments, is a critical part of any shipping operation. It is also important that vessel service life be protected by proper care, when handling cargo during loading and unloading. LoadMaster International has developed a suite of computer software designed to plan and optimize cargo forces and stresses on hulls regardless of the cargo type.

Another major goal when loading or unloading a vessel is to avoid overstressing any part of the vessel's structural design. Three critical factors that must be considered when loading a vessel are stability, stress, and trim.

• Stability: Stability is the way the vessel floats after loading and is related to the aggregate stress distribution on the hull. It answers the question: Where is the load relative to the vessel's center of gravity and are the forces balanced?
• Stress: Stress is the bending moment on each steel plate and bulkhead caused by the cargo placed in the vessel's hold. Bulkhead failures are the major reason for loading failures. Failures damage the vessel and create unscheduled repair expenses for vessel owners. They also result in unknown delays for vessel operators.
• Trim and heel: These factors have to do with vessel tilt. These should be a close to neutral as possible. The object of any loading procedure is to fill the vessel in such a way that all the forces acting on the individual steel plates, hull bulkhead dividers, and overall hull integrity are balanced and within the vessel's design limits.

Offshore decision tool

The goals of proper stress balancing and monitoring are:

• Safety - to stay within the tolerance margins set by the design of the vessel and the operator
• Economy - saving time and money so a vessel is used in an economically efficient manner
• Simulation - planning and modifying the load sequence to balance the stresses on a vessel's hull before loading begins.

SeaMax is software designed for any offshore structure. For decision support, SeaMax provides a comprehensive ballast advisor tool based on user-selected criteria or targets. The software can also provide damage stability calculations, for example, for compartment breaches. The software then uses the current load condition to recalculate the remaining stability.

The software is configurable for dual-mode operation. In monitoring mode, it tracks the real-time situation and makes use of automatic input from tank level gauging and other load measurement systems. When switched to simulation mode, the operator can perform planning. The monitoring mode continues to run in the background to provide warnings about the real-time situation of the vessel. These capabilities are especially important when adjusting anchoring limits, either with or without risers (for drilling vessels).

CargoMax can be used as a general cargo platform or can be purchased with feature modules designed for specific ship types: tankers, roll-on/roll-off ships, bulk carriers, or container vessels. This tool allows the master and officers to track with all cargo data, cargo planning, ship data, and ship stability calculations. Multiple reports on ship conditions and cargo operations are possible.

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