Calculates ship power (kW) using the propeller law.

calcShipPwrProp(
  shipSpeed,
  refSpeed,
  totalInstalledPwr,
  n = 3,
  serviceMargin,
  refSpeedType = "serviceSpeed"
)

Arguments

shipSpeed

Ship actual speed (m/s) (see calcSpeedUnitConversion)

refSpeed

Reference speed of the ship (service speed or maximum speed) (m/s)

totalInstalledPwr

Total installed main engine power (kW) (maximum continuous rated power)

n

Exponential relationship applied to the ship speed ratio (dimensionless). Default = 3

serviceMargin

A service margin to account for weather and sea effects:

  • At-sea operations = 15

refSpeedType

Indicates if the reference speed is service speed or maximum speed:

  • "serviceSpeed (Default)"

  • "maxSpeed"

Value

power

Details

Ship speed and actual draft are typically obtained from sources such as AIS messages or ship records.

serviceMargin = 10 or 15, based on IMO (Prpic Orsic and Faltinsen, 2012). 15 indicates 15% increased resistance in at-sea water conditions, and 10 indicates 10% increased resistance in coastal water conditions.

Note that service margin is treated as an added resistance here (instead of as a reduced efficiency) to maintain consistency with the other power models used in this library. (See MAN, 2011).

References

EPA. 2009. "Regulatory impact analysis: Control of emissions air pollution from category 3 marine diesel engines." Ann Arbor, MI: Office of Transportation and Air Quality. US Environmental Protection Agency.

MAN Energy Solutions. 2011. "Basic Principles of Propulsion."

See also

Examples

calcShipPwrProp(seq(10,14,1), 15, 9363, n=3, serviceMargin=0)
#> [1] 2304.225 3066.923 3981.700 5062.381 6322.792