Out with the Old, In with the New: Comparing Ballast Control Systems for the Hull

June 1, 2018

Comparing Conventional Hydraulic to Electro-Hydraulic Hull Systems

Conventional hydraulic systems are great for deep-water applications because they allow you to control a wide range of equipment. In a conventional hydraulic integrated ballast control system, the platform requires two or four central HPUs (hydraulic power unit) and the associated solenoid valve cabinets and accumulator racks. This field-proven design has been utilized on deep-water platform installations for decades. It is a tried-and-true hull automation solution that offers long service life, high reliability, and minimal required maintenance. However, from an installation perspective, central hydraulic systems might not be the most cost-effective option.

Today, a more cost-effective approach is an integrated electro-hydraulic hull solution. This solution incorporates an electrically-powered, PLC-controlled device that mounts directly to the hydraulic actuator and allows the operator to remotely open and close an automated valve assembly. This device is known as an LPU (local power unit). The LPU consists of a pump, reservoir, asynchronous capacitor motor, printed circuit board and logic manifold. This option eliminates the need for solenoid valve cabinets (for directing flow to the valve assembly), accumulator racks (for emergency shutdown operations), and miles of tubing. The obvious benefits include, but are not limited to, local control at the actuator and significant reduction in weight, oil volume, and space requirements. In other words, everything needed to operate the valve assembly is contained in one compact unit as opposed to two or four HPUs.

CapEx (Capital Expenditure) Comparison
In the offshore industry, CapEx costs are constantly being monitored so as to not exceed predetermined project budgets. The type of ballast control system utilized on a vessel can greatly influence this number. Factors that influence how a hull is automated include environmental considerations, installation costs, space availability, and weight. Consider the installation costs of a conventional hydraulic system. It is quite expensive because it requires the installation of thousands of feet of hydraulic tubing throughout the hull. However, conventional systems require more than just installing the tubing. Other requirements include flushing of the lines and penetration of multiple bulkheads. The installation costs associated with the conventional hydraulic ballast control system comprises the largest percentage of the CapEx value. Electro-hydraulic ballast control systems eliminate the aforementioned costs. As a result, this technology reduces capital expenditures and drives additional profitability.

High Torque of Hydraulics, Precise Control of Electronics
In an effort to optimize costs, today’s market is seeing a transition away from conventional hydraulic control systems and towards electro-hydraulic automation due to their environmentally-considerate design and high torque-to-weight ratios. Given the benefits of an electro-hydraulic integrated ballast control system, this design should be strongly considered as the most cost-effective solution for deep-water platform operators.

Jacob Shoesmith │ Marine/Offshore Integration Systems
Supreme Integrated Technology, Inc.