Prehistoric Seafaring Coiba

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WHAT IS IT?

Explore how simple boats and decision rules could enable travel between islands under variable winds, currents, and visibility.

HOW IT WORKS

Boats: Carry paddlers, have speed, heading, fatigue, and risk of capsizing. Islands: Targets and waypoints with elevation used to determine visibility range.

HOW TO USE IT

Wind and current vectors: Spatially varying fields updated stochastically each tick. Sea state: Derived from wind speed; affects capsize risk and effective speed.

THINGS TO NOTICE

Movement: Effective velocity = paddling + drift. v ⃗

boat

v ⃗ paddle + v ⃗ current + α ⋅ v ⃗ wind Wayfinding: Sightline hopping if islands are within visibility; otherwise dead-reckoning, downwind drift, or tacking. Fatigue: Reduces paddling speed over time; rest on land. Risk: Capsize probability grows with wind and wave exposure.

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; Prehistoric Seafaring in Coiba Archipelago
; Author: Copilot + Diana Carvajal
; NetLogo 6.x

breed [boats boat]
breed [islands island]

boats-own [
  speed-base
  speed-eff
  heading
  fatigue
  endurance-hours
  hours-paddled
  alive?
  route-target
  strategy
  reached-target?
]

islands-own [
  elev
  name
]

globals [
  km-per-patch
  hours-per-tick
  visibility-km
  wind-heading
  current-heading
  success-count
  failure-count
]

to setup
  clear-all
  set km-per-patch 2        ; 1 patch = 2 km
  set hours-per-tick 0.5    ; each tick = 30 minutes
  set visibility-km 30
  set wind-heading 225      ; NE trade winds (blowing SW)
  set current-heading 240   ; Panama Bight current
  set success-count 0
  set failure-count 0
  setup-islands
  setup-boats
  reset-ticks
end 

to setup-islands
  ; Approximate positions (replace with GIS coordinates if available)
  create-islands 1 [
    setxy 0 0
    set name "Coiba"
    set elev 416
    set color green
    set size 2
    set label name
  ]
  create-islands 1 [
    setxy 10 -5
    set name "Jicarón"
    set elev 322
    set color green
    set size 2
    set label name
  ]
  create-islands 1 [
    setxy 12 -8
    set name "Jicarita"
    set elev 180
    set color green
    set size 2
    set label name
  ]
  ; Add more islands: Cébaco, Papagayo, Canales, Montuoso...
end 

to setup-boats
  let origin one-of islands with [name = "Coiba"]
  create-boats 20 [
    setxy [xcor] of origin [ycor] of origin
    set color white
    set speed-base kmh-to-patches-per-tick 5
    set speed-eff speed-base
    set fatigue 0
    set endurance-hours 8
    set hours-paddled 0
    set alive? true
    set route-target one-of islands with [name != "Coiba"]
    set strategy one-of ["sight-hop" "dead-reckon" "downwind" "tack"]
    set heading towards route-target
  ]
end 

to go
  if not any? boats [ stop ]
  ask boats with [alive?] [
    navigate
    move
    check-landfall
  ]
  tick
end 

to navigate
  if strategy = "sight-hop" [
    let vis-radius patches-from-km visibility-km
    let seen islands in-radius vis-radius
    if any? seen [
      set heading towards min-one-of seen [distance myself]
    ]
  ]
  if strategy = "dead-reckon" [ set heading towards route-target ]
  if strategy = "downwind" [ set heading wind-heading ]
  if strategy = "tack" [
    if ticks mod 40 < 20 [ set heading (towards route-target) + 45 ]
    if ticks mod 40 >= 20 [ set heading (towards route-target) - 45 ]
  ]
end 

to move
  set speed-eff speed-base * (1 - fatigue * 0.5)
  fd speed-eff
  set hours-paddled hours-paddled + hours-per-tick
  if hours-paddled > endurance-hours [ set fatigue fatigue + 0.05 ]
end 

to check-landfall
  let nearby one-of islands in-radius 1
  if nearby != nobody [
    if nearby = route-target [
      set reached-target? true
      set success-count success-count + 1
      set color green
      die
    ]
  ]
end 

; Utility conversions

to-report kmh-to-patches-per-tick [kmh]
  report (kmh / km-per-patch) * hours-per-tick
end 

to-report patches-from-km [km]
  report km / km-per-patch
end

There is only one version of this model, created about 7 hours ago by Diana Carvajal.

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