calcCm.Rd
Calculates the midship section coefficient (Cm
)
(dimensionless).
calcCm( shipType, Cbw, maxDraft, actualDraft, CmEquationType, tankerBulkCarrierShipTypes = c("tanker", "chemical.tanker", "liquified.gas.tanker", "oil.tanker", "other.tanker", "bulk.carrier"), tugShipTypes = c("service.tug", "tug"), roroPaxShipTypes = c("ferry.pax", "ferry.ro.pax", "cruise", "cruise.ed", "yacht", "ro.ro", "passenger") )
shipType | Ship type (vector of strings, see |
---|---|
Cbw | Waterline block coefficient (vector of numericals, dimensionless)
(see |
maxDraft | Maximum summer load line draft (vector of numericals, m) |
actualDraft | Actual draft (vector of numericals, m) |
CmEquationType | Equation type:
This argument is not vectorized, as it takes only a single string |
tankerBulkCarrierShipTypes | Ship types specified in input |
tugShipTypes | Ship types specified in input |
roroPaxShipTypes | Ship types specified in input |
Cm
(vector of numericals, dimensionless)
The midship section coefficient calculation depends on the ship type, in addition to the actual draft. Actual draft is typically obtained from sources such as AIS messages or ship records.
This function can calculate Cm
using three different methods:
Kristensen, Benford, and Schneekluth. The Kristensen method requires ship
types to be grouped. Use the tankerBulkCarrierShipTypes
,
tugShipTypes
, and roroPaxShipTypes
parameters to provide these
ship type groupings. Any ship types not included in these groupings will be
considered as miscellaneous vessels.
Use the CmEquationType
parameter to indicate which method to use:
"kristensen" (see Kristensen 2013 & 2017):
Bulk Carriers and Tankers: Cm
= 0.995
Passenger Vessels: Cm
= 0.95
Tugboats: Cm
= 0.92
Miscellaneous Vessels: Cm
= 0.98
"benford" (see Rakke 2016): $$Cm=0.977+0.085*(Cbw-0.6)$$
"schneekluth" (see Schneekluth 1998): $$Cm=1.006-0.0056*Cbw^-3.65$$
Kristensen, H. O. and Lutzen, M. 2013. "Prediction of Resistance and Propulsion Power of Ships."
Kristensen, H. O. "Ship-Desmo-Tool." https://gitlab.gbar.dtu.dk/oceanwave3d/Ship-Desmo
Schneekluth, H. and Bertram, V. 1998. "Ship Design for Efficiency and Economy." 2nd ed. Oxford, Boston: Butterworth-Heinemann.
#> [1] 0.9945600 0.9778723calcCm(c("chemical.tanker","container.ship"),c(0.8,0.75),c(13.6,15.6),c(12.5,14.1),"kristensen", tankerBulkCarrierShipTypes=c("other.tanker"))#> [1] 0.9782400 0.9778723