calcPropPwr.Rd
Calculates ship power (kW) using the propeller law.
calcPropPwr( totalInstalledPwr, shipSpeed, refSpeed, serviceMargin = 15, n = 3, refSpeedType = "serviceSpeed" )
totalInstalledPwr | Total installed main engine power (vector of numericals, kW) (maximum continuous rated power) |
---|---|
shipSpeed | Ship actual speed (vector of numericals, m/s) (see
|
refSpeed | Reference speed of the ship (service speed or maximum speed) (vector of numericals, m/s) |
serviceMargin | A service margin to account for weather and sea effects:
Can supply either a vector of numericals, a single number, or rely on the default |
n | Exponential relationship applied to the ship speed ratio (dimensionless). Default = 3. This argument is not vectorized, so supply a single number or rely on the default |
refSpeedType | Indicates if the reference speed is service speed or maximum speed:
Can supply either a vector of strings, a single value, or rely on the default. |
power (vector of numericals, kW)
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).
MAN Energy Solutions. 2011. "Basic Principles of Propulsion."
calcPropPwr(totalInstalledPwr = 9363, shipSpeed = seq(10,14,1), refSpeed = 15, serviceMargin = 15, n = 3)#> [1] 2649.858 3526.961 4578.955 5821.739 7271.211