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Tuesday, December 07, 2010

Pac-Man Sunset

This is what Ben Wormeli called a "Pac-Man sunset."

We were heading north at 20 knots, making our implacable way NNW towards Los Angeles. There was a gentle-pitching motion to the ship (which remained with me for a day after leaving the ship).





In a display case on the Sapphire Princess a Wikipedia article was reproduced describing the distance to the horizon. This is a useful approximation: given a distance h (in feet) above the surface of the Earth of the human eye, the distance to the horizon (in miles) is about: d (miles) = SQRT(1.5 * h (ft)). The Sapphire Princess height is about 54 meters (nearly 18 floors tall). So that means pictures from the Sport Deck (floor 15?) will be about 149 feet above the surface, so the horizon will be about 14.9 miles away!

Here is a Web Page describing basic facts about the Sapphire Princess. The Princess Theater can seat 705 people!

Taking another look at the ship's plume, the red color betrays the presence of large amounts of nitrogen oxides (NOx) in the hot turbine exhaust.

Wikipedia describes the source of the propulsion power:
The diesel-electric plant consists of 4 diesel generators and a gas turbine generator. The diesel generators are Wartsilla 46 series common rail engines, two of the straight 9 cylinder configuration, and two of the straight 8 cylinder configuration. The 8 and 9 cylinder engines can produce approximately 8 1/2 and 9 1/2 MW of power respectively. These engines are fueled with Heavy Fuel oil (HFO or bunker c) and Marine Gas Oil (MGO) depending on the local regulations regarding emissions, as MGO produces much lower emissions but is much more expensive. The gas turbine generator is a GE 2500, producing a peak of 25 MW of power and being fueled my MGO. This generator is much more expensive to run than the Wartsilla generators, and is used mostly in areas, such as Alaska, where the emissions regulations are strict. It is also used when top speed is required to make it to a port in a short time period.

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