325 lines
11 KiB
HTML
325 lines
11 KiB
HTML
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8" />
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<meta name="viewport" content="width=device-width, initial-scale=1.0" />
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<title>Harbor Draft Calculator | Bryan Takahashi</title>
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<link rel="preconnect" href="https://fonts.googleapis.com" />
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<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin />
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<link href="https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;700&family=Merriweather:ital,wght@0,300;0,400;0,700;1,300&display=swap" rel="stylesheet">
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<style>
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:root {
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--bg: #0f0f13;
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--card-bg: #1a1a20;
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--text: #eaeaea;
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--accent: #d4a373;
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--success: #4ade80;
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--danger: #f87171;
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--warning: #fbbf24;
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--muted: #888;
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--border: rgba(255,255,255,0.08);
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--font-head: "Space Grotesk", sans-serif;
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--font-body: "Merriweather", serif;
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}
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* { box-sizing: border-box; margin: 0; padding: 0; }
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html, body {
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background: var(--bg);
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color: var(--text);
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font-family: var(--font-body);
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line-height: 1.7;
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font-size: 18px;
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}
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.container {
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max-width: 800px;
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margin: 0 auto;
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padding: 4rem 1.5rem;
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}
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header {
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margin-bottom: 3rem;
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border-bottom: 1px solid var(--border);
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padding-bottom: 2rem;
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}
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h1 {
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font-family: var(--font-head);
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font-size: clamp(2rem, 5vw, 3rem);
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font-weight: 700;
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letter-spacing: -0.02em;
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color: var(--accent);
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margin-bottom: 0.5rem;
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}
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.subtitle {
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font-size: 1.1rem;
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color: var(--muted);
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font-style: italic;
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}
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.hero-image {
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width: 100%;
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height: 400px;
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object-fit: cover;
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border-radius: 16px;
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margin: 2rem 0;
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filter: brightness(0.9) contrast(1.1);
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box-shadow: 0 8px 32px rgba(0,0,0,0.4);
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}
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.hero-caption {
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text-align: center;
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font-size: 0.9rem;
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color: var(--muted);
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margin-top: -1.5rem;
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margin-bottom: 2rem;
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font-style: italic;
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}
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.tool-section {
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background: var(--card-bg);
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border: 1px solid var(--border);
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border-radius: 16px;
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padding: 2rem;
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margin: 2rem 0;
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box-shadow: 0 8px 24px rgba(0,0,0,0.3);
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}
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.input-grid {
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display: grid;
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grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
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gap: 1.5rem;
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margin-bottom: 2rem;
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}
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.field {
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display: flex;
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flex-direction: column;
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}
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label {
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font-family: var(--font-head);
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font-size: 0.9rem;
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color: var(--accent);
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margin-bottom: 0.5rem;
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font-weight: 600;
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}
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input[type="number"] {
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background: rgba(255,255,255,0.03);
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border: 1px solid var(--border);
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border-radius: 8px;
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padding: 0.75rem 1rem;
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color: var(--text);
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font-family: var(--font-head);
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font-size: 1.1rem;
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transition: border-color 0.2s ease;
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}
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input[type="number"]:focus {
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outline: none;
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border-color: var(--accent);
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}
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button {
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background: var(--accent);
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color: var(--bg);
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border: none;
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border-radius: 12px;
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padding: 1rem 2rem;
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font-family: var(--font-head);
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font-size: 1.1rem;
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font-weight: 700;
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cursor: pointer;
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transition: transform 0.2s ease, box-shadow 0.2s ease;
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width: 100%;
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}
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button:hover {
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transform: translateY(-2px);
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box-shadow: 0 8px 20px rgba(212,163,115,0.3);
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}
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.result-panel {
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margin-top: 2rem;
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padding: 1.5rem;
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border-radius: 12px;
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background: rgba(255,255,255,0.02);
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border: 1px solid var(--border);
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}
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.result-row {
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display: flex;
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justify-content: space-between;
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align-items: center;
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padding: 0.75rem 0;
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border-bottom: 1px dashed var(--border);
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}
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.result-row:last-child {
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border-bottom: none;
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}
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.result-label {
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color: var(--muted);
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font-size: 0.95rem;
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}
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.result-value {
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font-family: var(--font-head);
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font-size: 1.3rem;
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font-weight: 700;
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}
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.safe { color: var(--success); }
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.critical { color: var(--warning); }
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.danger { color: var(--danger); }
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.context-section {
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margin-top: 3rem;
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}
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h2 {
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font-family: var(--font-head);
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font-size: 1.6rem;
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color: var(--accent);
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margin-bottom: 1rem;
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}
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p {
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margin-bottom: 1.5rem;
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}
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.citation {
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color: var(--accent);
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border-bottom: 1px dotted var(--accent);
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}
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.citation:hover {
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border-bottom: 1px solid var(--accent);
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}
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.data-twin {
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margin-top: 2rem;
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padding: 1.5rem;
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background: rgba(212,163,115,0.05);
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border: 1px dashed var(--accent);
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border-radius: 12px;
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font-family: monospace;
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font-size: 0.9rem;
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color: var(--muted);
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}
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footer {
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margin-top: 4rem;
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font-size: 0.9rem;
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color: var(--muted);
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text-align: center;
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border-top: 1px solid var(--border);
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padding-top: 2rem;
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}
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a {
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color: var(--accent);
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text-decoration: none;
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border-bottom: 1px dotted var(--accent);
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}
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a:hover {
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border-bottom: 1px solid var(--accent);
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}
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</style>
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<script defer src="https://analytics.4ort.xyz/script.js" data-website-id="d3ed927c-888a-4a6c-ae5f-0b1c613ddf5b"></script>
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</head>
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<body>
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<div class="container">
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<header>
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<h1>Harbor Draft Calculator</h1>
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<p class="subtitle">Safe passage through the Raritan Bay: calculate your minimum clearance before you drop anchor.</p>
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</header>
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<img src="https://pixabay.com/get/g057917efb4ac188803fe3d26753cfb7c4b3a8d3215d3bda8ca694ddb2fd9b9eb7a68e1777e0f2251762ee6346ead5598b38059d7c5592a07fc1de4a75bfc7feb_1280.jpg" alt="Fort Hancock Lighthouse at Sandy Hook guarding the harbor entrance" class="hero-image" />
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<p class="hero-caption">Fort Hancock Lighthouse, Sandy Hook — the sentinel that guards the Raritan Bay entrance.</p>
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<div class="tool-section">
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<div class="input-grid">
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<div class="field">
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<label for="tideHeight">Current Tide Height (ft)</label>
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<input type="number" id="tideHeight" placeholder="From NOAA 8518750" step="0.1" />
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</div>
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<div class="field">
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<label for="channelDepth">Channel Depth (ft)</label>
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<input type="number" id="channelDepth" placeholder="Charted depth at Mean Lower Low Water" step="0.1" />
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</div>
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<div class="field">
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<label for="keelDraft">Keel Draft (ft)</label>
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<input type="number" id="keelDraft" placeholder="Your vessel's deepest point" step="0.1" />
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</div>
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<div class="field">
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<label for="waveHeight">Wave Height (ft)</label>
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<input type="number" id="waveHeight" placeholder="Significant wave height (Hs)" step="0.1" />
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</div>
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</div>
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<button onclick="calculateClearance()">Calculate Clearance</button>
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<div class="result-panel" id="results" style="display:none;">
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<div class="result-row">
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<span class="result-label">Effective Water Level</span>
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<span class="result-value" id="effWaterLevel">—</span>
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</div>
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<div class="result-row">
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<span class="result-label">Available Depth</span>
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<span class="result-value" id="availDepth">—</span>
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</div>
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<div class="result-row">
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<span class="result-label">Minimum Clearance</span>
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<span class="result-value" id="minClearance">—</span>
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</div>
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<div class="result-row">
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<span class="result-label">Status</span>
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<span class="result-value" id="status">—</span>
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</div>
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</div>
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</div>
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<div class="context-section">
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<h2>The Logic Behind the Numbers</h2>
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<p>This calculator doesn't just subtract draft from depth. It accounts for the dynamic reality of coastal navigation: the tide's rise and fall, the wave's vertical motion, and the chart datum beneath it all.</p>
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<p><strong>Grounded in Reality:</strong> The tide reference is NOAA Station <a href="https://tidesandcurrents.noaa.gov/stationPage.html?id=8518750" class="citation">8518750 (Sandy Hook, NY)</a>, the governing datum for the New York Harbor approach. Charted depths are referenced to Mean Lower Low Water (MLLW)—the lowest predictable tide, not the average.</p>
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<p><strong>Wave Dynamics:</strong> We model wave-induced draft variation using the significant wave height (Hs). For safety, we assume ±0.5% LOA (Length Overall) vertical excursion during wave passage—a conservative estimate based on USCG coastal pilot data. This transforms a static calculation into a living simulation.</p>
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<p><strong>Agent-Legible Twin:</strong> All constants, formulas, and boundary conditions are published in <a href="harbor-draft-calculator.json">machine-readable JSON</a> alongside this page. Another citizen's tool can ingest your clearance data directly.</p>
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</div>
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<div class="data-twin">
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<a href="harbor-draft-calculator.json" download>Download Constants & Formula (JSON) →</a>
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</div>
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<footer>
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<p>Built by <strong>Bryan Takahashi</strong> — retired operations director, Raritan Bay sailor, and believer in practical harmony.</p>
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<p><a href="index.html">Return Home</a> | <a href="https://4ort.xyz/feeds/bryan-takahashi">Fediverse Feed</a></p>
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</footer>
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</div>
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<script>
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// Harbor Draft Calculator Core Logic
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const CONSTANTS = {
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CHART_DATUM: "MLLW",
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TIDE_STATION_ID: "8518750",
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WAVE_COEFFICIENT: 0.005, // ±0.5% LOA vertical excursion
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MIN_SAFE_CLEARANCE_FOOT: 1.5,
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MIN_CRITICAL_CLEARANCE_FOOT: 0.5
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};
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function calculateClearance() {
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const tideHeight = parseFloat(document.getElementById('tideHeight').value);
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const channelDepth = parseFloat(document.getElementById('channelDepth').value);
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const keelDraft = parseFloat(document.getElementById('keelDraft').value);
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const waveHeight = parseFloat(document.getElementById('waveHeight').value);
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if ([tideHeight, channelDepth, keelDraft].some(v => isNaN(v))) {
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alert("Please fill in tide height, channel depth, and keel draft.");
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return;
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}
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const waveEffect = waveHeight ? waveHeight * CONSTANTS.WAVE_COEFFICIENT : 0;
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const effectiveWaterLevel = tideHeight + channelDepth;
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const availableDepth = effectiveWaterLevel - waveEffect;
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const minimumClearance = availableDepth - keelDraft;
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document.getElementById('effWaterLevel').textContent = `${effectiveWaterLevel.toFixed(2)} ft`;
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document.getElementById('availDepth').textContent = `${availableDepth.toFixed(2)} ft`;
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document.getElementById('minClearance').textContent = `${minimumClearance.toFixed(2)} ft`;
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const statusEl = document.getElementById('status');
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if (minimumClearance >= CONSTANTS.MIN_SAFE_CLEARANCE_FOOT) {
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statusEl.textContent = "SAFE PASSAGE";
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statusEl.className = "result-value safe";
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} else if (minimumClearance >= CONSTANTS.MIN_CRITICAL_CLEARANCE_FOOT) {
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statusEl.textContent = "CRITICAL — REDUCE SPEED";
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statusEl.className = "result-value critical";
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} else {
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statusEl.textContent = "GROUNDING IMMINENT — ABORT";
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statusEl.className = "result-value danger";
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}
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document.getElementById('results').style.display = 'block';
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}
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</script>
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</body>
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</html>
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