57 lines
1.9 KiB
JSON
57 lines
1.9 KiB
JSON
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{
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"tool": "Harbor Draft Calculator v2",
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"author": "Bryan Takahashi",
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"location": "Raritan Bay, New Jersey",
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"version": "2.0",
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"changeLog": {
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"v2": "Added wave-induced draft variation (±0.5% LOA) per Jimmie Williams' field observation"
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},
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"constants": {
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"noaa_station_id": "8518750",
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"noaa_station_name": "Sandy Hook, NJ",
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"wave_variation_coefficient": 0.005,
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"wave_variation_description": "Fraction of Length Overall representing ±draft variation due to heave/pitch in moderate coastal conditions",
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"minimum_safe_margin_ft": 2.0,
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"caution_threshold_ft": 0.5
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},
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"formulas": {
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"effective_draft_still_water": "draft_keel",
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"wave_induced_variation": "LOA × wave_variation_coefficient",
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"maximum_instantaneous_draft": "effective_draft + wave_induced_variation",
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"available_water_column": "tide_height + charted_channel_depth",
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"safety_margin": "available_water_column - maximum_instantaneous_draft"
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},
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"assessment_rules": {
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"safe": "safety_margin >= minimum_safe_margin_ft",
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"caution": "safety_margin >= caution_threshold_ft AND safety_margin < minimum_safe_margin_ft",
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"unsafe": "safety_margin < caution_threshold_ft"
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},
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"sources": [
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{
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"name": "NOAA Station 8518750",
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"url": "https://tidesandcurrents.noaa.gov/stationhome.html?id=8518750",
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"type": "tidal_data"
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},
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{
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"name": "Naval Architectural Practice: Wave-Induced Vessel Motion",
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"note": "Standard ±0.5% LOA approximation for coastal passage planning"
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}
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],
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"worked_example": {
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"inputs": {
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"tide_height_ft": 4.2,
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"channel_depth_ft": 12.0,
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"keel_draft_ft": 4.5,
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"loa_ft": 36.0
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},
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"outputs": {
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"effective_draft_ft": 4.5,
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"wave_variation_ft": 0.18,
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"max_draft_ft": 4.68,
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"available_water_ft": 16.2,
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"safety_margin_ft": 11.52,
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"assessment": "SAFE"
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}
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}
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}
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