Spill Tools Exercise:
The Mechanical Equipment Calculator

In this step of the Spill Tools exercise, you'll estimate how much of the spilled oil you could skim off the sea surface during the time remaining before the oil is predicted to reach the sensitive site. You have on hand a single, small skimmer vessel, a Sandpiper (skimmers are boats and other devices that can remove oil from the sea surface before it reaches sensitive areas along a coastline). Here's how to use the Calculator to make the necessary calculations:

1. Create and name a new scenario.  To do this, click New Scenario, type in the name of your scenario, then click OK.

2. Assign the Sandpiper platform to your scenario. To do this, click Go to Platform, click on the Sandpiper in the list of skimmers, then click OK. You will see information about the characteristics of the Sandpiper. Next, click Scenario Assignments, click on the name of your scenario, click >>Move>>, then click OK.

The Calculator shows you information about the Sandpiper obtained from the manufacturer or estimated by oil spill response experts, including its Service Type (the mechanism it uses to skim oil) and Operating Environment (the environment it is designed to function in). Note in particular the Nameplate Pump Rate, shown in the lower left corner of the window. This is the maximum rate at which the Sandpiper can skim fluid from the water surface, under ideal conditions (in real life, consider reducing this value if you are attempting a skimming operation in rough seas). When using the Calculator for a real response, adjust Offload, Transit, and Utilization Times to match your situation. These are the times taken (a) to offload collected fluids from the skimmer and (b) to complete a one-way transit to the transfer point, and (c) the time available to collect and recover fluids, transit to and from backup storage, and offload recovered fluids. For more details about the information you see on your screen, click ?.

Change Utilization Time to 10 hours, since you have an estimated 10 hours before the oil slick reaches the sensitive site.

3. Return to your scenario: from the Scenario menu, choose the name of your scenario, then click Go to Scenario.

The Calculator will add the Sandpiper to its list of skimmers used for this scenario, and its UT, Utilization Time.

4. Fill out the boxes in the Calculator to describe your spill scenario, as shown below.

• Under Operational Period, to indicate when the skimmer can start working and when it will stop working, type in Start and End dates and times. You have just 10 hours to skim oil from the slick before it is predicted to reach the sensitive site, so type in a Start date/time and End date/time that are 10 hours apart (as in the example below). Note that the Calculator uses the 24-hour time system, in which time of day is indicated by four digits, the first two indicating the hour (00 to 23) and the last two indicating the number of minutes past that hour (00 to 59). Each day begins at midnight, 0000, and the last minute of each day is 2359.
  
• Type in the Volume and Area of the slick, and choose units (the Calculator then will automatically estimate Thickness).

5. Click Calculate. The Calculator will use the information you entered to predict

• Area Covered - the area of the slick that the Sandpiper can skim during your 10-hour operational period.
  
• Fluid Recovered - the total amount of oil and water the Sandpiper can collect in 10 hours.
  
• Fluid Retained - the total amount of fluid the Sandpiper will retain in its hold after 10 hours (some skimmers can decant water as they skim; the Sandpiper cannot).
  
• Oil/Emulsion Recovered - out of the total fluid recovered, the amount that is either oil or emulsion (a frothy mixture of oil and water, often called mousse).

• Free Water Recovered - out of the total fluid recovered, the amount that is free water (water that is not emulsified with oil).
  
• Free Water Retained - the amount of water the Sandpiper will retain in its hold after 10 hours
  
• Free Water Decanted - the amount of water the Sandpiper will decant as it skims (this value will be zero, since the Sandpiper does not decant water)
  
• Time to Fill - The time taken by the Sandpiper to fill its hold with fluid (once the hold is full, the Sandpiper must transit to a location where it can offload the fluid it has collected).
  
• Number of Fills - The number of times the Sandpiper can fill its hold with recovered fluids during the Utilization Time.

(Cost per Barrel [Cost/bbl], the cost in U.S. dollars per recovered barrel of oil, would be estimated if you had entered the hourly cost of operating the Sandpiper.)