{
 "version": "2026-10-20",
 "license": "Dimension sheets: CC BY 4.0. Standard and published-size files: CC BY 4.0. Xem Studio's own designs (files_license = Xem Studio Design License): free to use and sell things from, not to redistribute as files — https://xemstudio.com/license/. Other publishers' files: their own license, linked beside them.",
 "slug": "lifting-strakes",
 "name": "Lifting strakes and spray rails",
 "kind": "standard",
 "category": "Boat design",
 "group": "Hull types",
 "year": null,
 "question": "What do lifting strakes do?",
 "tags": [
  "vehicle design",
  "hull types",
  "rc design",
  "aerodynamics"
 ],
 "aliases": [
  "lifting strakes",
  "spray rails",
  "hull strakes",
  "boat strakes",
  "strakes planing",
  "rc boat strakes",
  "spray strakes",
  "running strakes"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/lifting-strakes/",
 "sheet_txt": "https://xemstudio.com/objects/lifting-strakes/sheet.txt",
 "sheet": {
  "basis": "Design rules and figures from the cited sources; example geometry by Xem Studio",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Lifting strakes are lengthwise steps on each side of the keel that add small flat surfaces, raising running attitude and top speed at the cost of weight and wetted area (Boat Blurb).",
   "Spray rails are lengthwise additions that knock spray down before it reaches occupants (Boat Blurb).",
   "The file is a reference example built by Xem Studio from the numbers above (Reference RC mono: 585 mm length and 20 deg transom deadrise (SV Design Stealthwake data); 181 mm is an unlabelled width in the same source's deadrise diagram.). Sizes the sources do not fix are illustrative; scale the example to your own vehicle."
  ],
  "table": {
   "columns": [
    "parameter",
    "value or range",
    "source"
   ],
   "rows": [
    [
     "Effect",
     "higher running attitude, more top speed",
     "Boat Blurb"
    ]
   ]
  }
 },
 "sheet_text": "Lifting strakes and spray rails — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/lifting-strakes/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)\nBasis: Design rules and figures from the cited sources; example geometry by Xem Studio\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Lifting strakes are lengthwise steps on each side of the keel that add small flat surfaces, raising running attitude and top speed at the cost of weight and wetted area (Boat Blurb).\n- Spray rails are lengthwise additions that knock spray down before it reaches occupants (Boat Blurb).\n- The file is a reference example built by Xem Studio from the numbers above (Reference RC mono: 585 mm length and 20 deg transom deadrise (SV Design Stealthwake data); 181 mm is an unlabelled width in the same source's deadrise diagram.). Sizes the sources do not fix are illustrative; scale the example to your own vehicle.\n\nparameter  value or range  source\nEffect  higher running attitude, more top speed  Boat Blurb\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Boat Blurb: Where is a chine on a boat and what does it do? — web — Publisher's page; dimensions are facts — https://www.boatblurb.com/post/where-is-a-chine-on-a-boat-and-what-does-it-do\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/lifting-strakes/index.json\nAPI: https://xemstudio.com/api/geometry?object=lifting-strakes\n",
 "sources": [
  {
   "publisher": "Boat Blurb",
   "title": "Where is a chine on a boat and what does it do?",
   "url": "https://www.boatblurb.com/post/where-is-a-chine-on-a-boat-and-what-does-it-do",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "deep-v-hull",
  "modified-v-hull",
  "flat-bottom-hull",
  "cathedral-tri-hull",
  "tunnel-hull-catamaran",
  "three-point-hydroplane"
 ],
 "fits": [],
 "dimensions": "exact (nominal, no printing tolerance)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no printing tolerance. Where a part meets another part, the object lists its mating features (feature, exact size, what it mates with, fit class: press, slide, run, socket, clamp or designed). Apply your process's allowance to those features only; 'designed' gaps are part of the design and stay as drawn.",
 "mating": [],
 "faq": [
  {
   "q": "Any downside?",
   "a": "Added weight and wetted surface (Boat Blurb)."
  }
 ],
 "files_license": {
  "name": "Xem Studio Design License",
  "holder": "Xem Studio",
  "url": "https://xemstudio.com/license/",
  "note": "Xem Studio's own design: free to use, print, modify and sell things made from it; not to be republished or redistributed as files."
 },
 "offers": [
  {
   "file": "lifting-strakes-hull",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/lifting-strakes/lifting-strakes-hull.step",
   "stl": "https://xemstudio.com/files/hardware/lifting-strakes/lifting-strakes-hull.stl",
   "note": "deep v hull, 585 × 181 mm, deadrise 22° (sections illustrative, scale to your boat)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/lifting-strakes/index.md"
}