ABSTRACT
Dispersants are a proven oil spill response technique. Since effective use of dispersants is often limited to a few days following a spill, timely and effective dispersant application is a major requirement for dispersant use. Despite the advantages of aircraft over vessels in applying dispersant to large or remote spills, vessels do offer certain advantages over aircraft. These include wide and ready availability in port and marine terminal areas, lower cost, ease of deployment, high degree of spray control and accuracy. These advantages often result in vessel platforms being the preferred application method, especially for nearshore, smaller spills. Therefore, vessel-based systems should not be overlooked in contingency planning, as these systems can often be a viable and effective option for sustained dispersant application in certain oil spill situations.
There are three major types of vessel dispersant application systems: (1) spray arm systems; (2) fire monitor systems, which are systems designed to spray water or fire-fighting foam; and (3) single nozzle neat dispersant application systems. The advantages and disadvantages of each system are reviewed and evaluated.
Certain vessel characteristics beneficial for dispersant application also are discussed. To be most effective, vessels generally should (1) have sufficient dispersant payload or the ability to be re-supplied effectively, (2) be rapidly mobilized shortly after dispersant use approval, and (3) be located close enough to the spill scene to arrive within the required time when dispersant use is effective. Finally, the major vessel dispersant application operational guidelines are summarized.