save temp.old
write (macros) temp.mac
clear macros
clear variables
report off
page 1

variable nprop:1:3
variable power:1:99999
variable diam:0.1:999
variable sfract:0:1
variable harm:0:999
variable beam:1:9999
variable q,q1,coef,gmreq,maxvcg,kfact,draft,ddraft,n
variable (string) t,powunit,lenunit
variable (string) proj,self
variable draft1:0.1:99,draft2:0.1:99,ndrafts:1:50

set proj="173095b"

set self="173095B.RF"

template about
 "Calculates required GM and maximum VCG as a function of"
 "draft at zero trim using the Towline Pull Criterion as"
 "given in 46 CFR 173.095 (b)."
/

macro readgf
 template t "Note"
  "No geometry file has been read."
  "Do you want to locate and Read one now?"
  "Yes" "No" exit
 //
 .t
 if {templok}=0 then exit
 template t "Geometry file"
  "Read" file t /ext:"gf" /exist
 //
 .t
 if {templok}=0 then exit
 read "{t}"
/

macro readsave
 run {proj}.sav /call
 cls
/

macro save
 report off
 save {proj}.sav
/

macro checkval
 if "%1"="" then set t="missing" | exit
 if %1<%2 then set t="too small" | exit
 if %1>%3 then set t="too large" | exit
 set t=""
/

macro coef
 set q = {power} times {diam}
 set q = {q} power 0.6667
 set coef = {q} times {nprop} times {sfract} times {harm} times {beam}
 set coef = {coef} div {kfact}
/

macro gmreq
 set gmreq=9999
 set maxvcg=-9999
 heel 0 | trim 0
 draft {draft}
 solve weight, lcg
 set q = {FREEBD}
 template t "Error"
  "Freeboard ({q}) is {t}."
 //
 .checkval "{q}" 0.0001 9999 | if "{t}"<>"" then .t | exit
 set q1 = {coef} div {q}
 set q = {WEIGHT}
 template t "Error"
  "Displacement ({q}) is {t}."
 //
 .checkval "{q}" 0.5 9999999 | if "{t}"<>"" then .t | exit
 set gmreq = {q1} div {q}
 set maxvcg = {BMT} plus {VCB} minus {gmreq}
/

template whatsfr
 "s is that fraction of the projected propeller circle"
 "that would be intercepted by the rudder turned 45 degrees"
 "from centerline."
/
template whathar
 "h is the vertical distance from propeller shaft centerline"
 "at rudder to the towing bitts."
/

template dialog "46 CFR 173.096 (b) Wizard"
 ""                        |  "About" .about /noverify
 "Number of propellers (N)"   nprop
 "Shaft power per shaft (P)"  power    | "{powunit}"
 "Propeller diameter (D)"     diam     | "{lenunit}"
 "s"                          sfract   | "?" .whatsfr /noverify
 "h"                          harm     | "?" .whathar /noverify
 "Molded beam (B)"            beam     | "{lenunit}"
 "Least draft"                draft1   | "{lenunit}"
 "Greatest draft"             draft2   | "{lenunit}"
 "Number of drafts"           ndrafts
 ""                        | "Report" .calc
/

macro rephead
 \     Draft        Displ       Freebd      GM req     max VCG\
 \------------------------------------------------------------\
/

macro report
 \{ draft:3}  { WEIGHT:1}  { FREEBD:3} {  gmreq:3} { maxvcg:3}\
/

macro dodraft
 .gmreq
 .report
 set draft={draft} plus {ddraft}
/

macro calc
 report {proj}.pf
 \\\\GM required according to CFR 173.095 (b)\
 \\N = {nprop}  P = {power} {powunit}  D = {diam:2} {lenunit}\
 \\s = {sfract:3}  h = {harm:2} {lenunit}  B = {beam:2} {lenunit}\
 \
 set n={ndrafts} minus 1
 set ddraft={draft2} minus {draft1} div {n}
 set draft={draft1}
 .rephead
 .coef
 .dodraft({ndrafts})
 \---------------- Displacement in {WUNIT} ----------------\
 view
 report off
 template t "Note"
  "You can print this report through the Report pulldown menu."
  "The report file name is {proj}.pf"
  "Ok" EXIT
 //
 .t
/

macro metric
 set powunit="kilowatts"
 set lenunit="meters"
 set kfact=13.93
/
macro english
 set powunit="horsepower"
 set lenunit="feet"
 set kfact=38.0
/

macro dodialog
 screen nohead
 me "46 CFR 173.095 (b) Wizard\
 .dialog
 if {templok}=0 then exit
 .save
/

macro init
 set nprop=1
/

macro esc
 template t "Error"
  "Error encountered in running {proj}.sav."
  "Restart" "Exit" EXIT
 //
 macro recover
  set error=0
  erase {proj}.sav
  run {self}
 //
 .t
 if {templok}<>0 then exit recover
/
if fexist {proj}.sav then .readsave /call else .init
macro esc
/

if "{LUNIT}"="FEET" then .english else .metric

if "{gf}"="" then .readgf
if "{gf}"<>"" then .dodialog

clear macros
clear variables
macro restore
 run temp.old /call
 template t "Note"
  "Original condition restored."
 //
 .t
/
if {templok}=0 then .restore
macro restore
/
run temp.mac /call
scr head
erase temp.mac
erase temp.old