{
  "title": "Light Guard",
  "era": "Comparative working barge form, before 1903",
  "version": "1.1",
  "modelStatus": "Interpretive reconstruction; no original lines plan recovered",
  "detailLevel": "full",
  "units": "metres",
  "axes": {
    "up": "+Y",
    "bow": "-X",
    "starboard": "+Z"
  },
  "historicalDimensions": {
    "lengthFeet": 143,
    "beamFeet": 27,
    "depthOfHoldFeet": null,
    "beamInferred": false,
    "holdDepthUnknown": true,
    "dimensionsSourceQuality": "Selected documentary baseline; see vessel research notes for length and beam conflicts"
  },
  "geometryReference": {
    "hullBowX": -21.793200000000002,
    "hullSternX": 21.793200000000002,
    "deckY": 3.9,
    "waterlineY": 2.7,
    "waterlineIsInferred": true
  },
  "bounds": {
    "min": [
      -25.085092516106297,
      0.0050000000000000044,
      -4.199800000000001
    ],
    "max": [
      21.878200000000003,
      27.903407959928714,
      4.199800000000001
    ]
  },
  "triangleCount": 45894,
  "trianglesByGroup": {
    "hull": 12950,
    "bulwarks": 9370,
    "fittings": 3068,
    "deck": 6706,
    "propulsion": 52,
    "anchors": 636,
    "deckhouses": 1056,
    "skylights": 64,
    "spars": 3116,
    "standing_rigging": 3456,
    "running_rigging": 504,
    "furled_canvas": 2280,
    "cargo_hatches": 120,
    "hatch_covers": 288,
    "steering": 412,
    "ship_boat": 1816
  },
  "drawCalls": 49,
  "mastCount": 3,
  "supportsSails": false,
  "visibilityNodes": {
    "hatches": "hatch_covers"
  },
  "deployedSailCount": 0,
  "inferredFeatures": [
    "Underwater hull lines and draft",
    "Exact colors, fittings, hatch layout and rigging routes"
  ],
  "configurationCaveat": "NOAA establishes the canal-sized schooner barge, but no securely identified complete portrait or rig plan was recovered. Three bare masts, low aft cabin and hatches are a comparison-based interpretation informed by an ambiguously attributed fleet image. Exact rig and deck layout remain uncertain.",
  "sources": [
    {
      "title": "NOAA vessel record",
      "url": "https://thunderbay.noaa.gov/shipwrecks/gilchrest_fleet.html",
      "use": "Vessel identity, scale, history and surviving evidence"
    },
    {
      "title": "Ambiguously attributed fleet photograph",
      "url": "https://commons.wikimedia.org/wiki/File:Knight_Templar_or_Light_Guard.png",
      "use": "Comparative hull and deck context; not securely identified Light Guard"
    },
    {
      "title": "WHS Sailing Canallers regional context",
      "url": "https://www.wisconsinshipwrecks.org/Files/canaller-regional-context.pdf",
      "use": "Canal-size hull family; comparisons do not establish this ship’s exact rig"
    },
    {
      "title": "Knight Templar secondary record",
      "url": "https://greatlakesrex.wordpress.com/k/",
      "use": "Nearby fleet-vessel rig comparison, not direct evidence of Light Guard mast count"
    }
  ],
  "revisedDate": "2026-09-08",
  "revisionNote": "Added sourced documentary features and repaired metadata and research-note formatting; this collection cleanup is not a new full historical or geometry audit.",
  "documentedFeatures": [
    "Wooden schooner barge built at Detroit by J.M.Jones in 1866. [NOAA vessel record](https://thunderbay.noaa.gov/shipwrecks/gilchrest_fleet.html)",
    "NOAA catalogue dimensions 143×27 ft. [NOAA vessel record](https://thunderbay.noaa.gov/shipwrecks/gilchrest_fleet.html)"
  ]
}