`Launch example - stern first
proj launch
read fv.gf

lwl = 80

weight 160, 3.60f, 0, 10.5  `<--- Total ship weight, LCG, TCG, VCG
draft 0 @ 40f, 5 @ 40a  `<--- Initial waterplane (partly down ways)

variable d
set d = {weight} minus {displ} `<-- d is initial weight on ways
set d = {d} times 0.90  `<-- most but not all for midship supports

ground "Midship supports" {d}, {lcg}, 0, 0 /pen:0,0.02
ground "Forward poppet" *, 40f, 0, 0  `<--- Poppet location (l,t,v)
ground "Aftmost support point" *, 40a, 0, 0  `<--- to keep from tipping aft

macro step
solve trim
status displ
set d = {depth} plus 1.0 `<--- use suitable increment
depth = {d}
/

.step (6)  `<--- use suitable number of steps