Water on Deck

GHS provides two special tank types for the purpose of modeling the effects of the extra burden of water on deck due to waves.
The first, FLOODED PLUS, is an extension of the FLOODED type. It raises the flooded waterplane above the external waterplane by an amount such that the increased volume is equal to the volume indicated by the LOAD setting.
The other type is called DECK. It is similar to the DAMAGED type with LOAD = 0 and an additional head of water added to that of the external waterplane. The parameter /HW: must be included with the TYPE command in order to specify the value of the additional head.
Following is a run which demonstrates the use of these types to model the two methods of treating water on deck.
macro makeship clear enter pm create hull ends 0 100 top 20 bot 0 out 10 // create deck.c ends 15 85 bot 8 fit hull // display write quit pm / macro interp `%1=x, %2=x1, %3=y1, %4=x2, %5=y2, %6=result var name if %1<%2 then set %6 = %3 | exit if %1>%4 then set %6 = %5 | exit variable t set t = %4 minus %1 times %3 set %6 = %1 minus %2 times %5 plus {t} set t = %4 minus %2 set %6 = {%6} div {t} / macro wod type = flood solve variable hw,f,v variable (string) u set u = "{wunit}" unit mt .interp {HEIGHT}, .3, .5, 2, 0, "hw" .interp {hs}, 1.5, 0, 4, 1, "f" set hw = {hw} times {f} if %1="NEU" then type = deck /hw:{hw} mac t type = intact heel = 0 | trim = 0 load = .5 solve depth set f = {HEIGHT} set v = {TVOLUME} set f = {f} minus 0.1 load = height:{f} solve depth set v = {TVOLUME} minus {v} times 10 \\Deck area is {v} sq. meters\ set v = {v} times {hw} contents = fw load = weight:{v} type = flood plus // if %1="POE" then .t unit {u} solve / macro stat \With water on deck, wave height: {hs} meters hw: {hw} meters\ status / macro ra heel = 0 ra /area /nowarn /
`===== Start of project commands ====== `Get geometry project testwod if fexist {project}.gf then read else .makeship report /nograph
`Set ship weight and C.G. draft = 4.5 vcg = 5 solve weight, lcg
`Set point of damage variable pod set pod = "50a, 10s, 8" `Point of damage, also used to determine freeboard. refpt (hull) = {pod}
`Select deck to be flooded tank deck.c refpt = {pod} type = flood
`Induce heeling moment tcg = 0.5
\\==== Initial condition without water on deck: ====\ solve status
`Set wave height variable hs set hs = 2.75 `Wave height in meters
macro case page \\%2 method\ .wod %1 .stat .ra /
.case neu "Northern European" .case poe "Panel-of-Experts"

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