Calculate incremental hull (roughness) resistance coefficient (Ca) (dimensionless), which describes the effect of hull roughness and still-air resistance, using the Holtrop & Mennen method.

calcHMCa(maxDraft, lwl, Cbw, breadth, forwardDraft, Abt, hb)

Arguments

maxDraft

Maximum summer load line draft (vector of numericals, m)

lwl

Waterline length (vector of numericals, m) (see calclwl)

Cbw

Waterline block coefficient (vector of numericals, dimensionless) (see calcCbw)

breadth

Moulded breadth (vector of numericals, m)

forwardDraft

Forward draft (deviation from actual draft indicates trim) (vector of numericals, m)

Abt

Traverse bulb area (vector of numericals, m^2) (see calcAbt)

hb

Center of bulb area above keel line (vector of numericals, m) (see calchb)

Value

Ca (vector of numericals, dimensionless)

References

Holtrop, J. and Mennen, G. G. J. 1982. "An approximate power prediction method." International Shipbuilding Progress 29.

See also

Examples

calcHMCa(c(13.57,11.49),c(218.7500,209.2518),c(0.81,0.65),c(32.25,32.20),c(13.57,11.49), c(25.09,55.86),c(5.43,4.6))
#> [1] 0.0003356088 0.0003471836
calcHMCa(13.57,218.7500,0.81,32.25,13.57,25.0880,5.428)
#> [1] 0.0003356088