{
 "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": "surface-piercing-drive",
 "name": "Surface drive (surface-piercing propeller)",
 "kind": "standard",
 "category": "Boat design",
 "group": "Hull types",
 "year": null,
 "question": "What is a surface drive and why use a surface-piercing prop?",
 "tags": [
  "vehicle design",
  "hull types",
  "rc design",
  "aerodynamics"
 ],
 "aliases": [
  "surface drive",
  "surface piercing propeller",
  "stinger drive",
  "rc surface drive",
  "cleaver prop",
  "half submerged prop",
  "surface propeller",
  "arneson drive",
  "surface drive vs submerged"
 ],
 "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/surface-piercing-drive/",
 "sheet_txt": "https://xemstudio.com/objects/surface-piercing-drive/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": [
   "A surface drive runs the propeller only partly submerged near the water surface. Removing shafts, struts and hubs from the water cuts appendage drag, and the prop can be large and lightly loaded; ventilation replaces cavitation (ITU lecture).",
   "Drawbacks are vibration, poor reverse, difficult turns, harder set-up and poor efficiency at low rpm. Cleaver props suit speeds above ~50 knots (ITU).",
   "RC 'stinger' drives position the prop similarly; racers report no difference in hull behaviour if the prop sits in the same place (Model Gas Boats forum).",
   "The file is a reference example built by Xem Studio from the numbers above (44 mm x 1.4 pitch ratio RC mono prop (SV Design).). Sizes the sources do not fix are illustrative; scale the example to your own vehicle."
  ],
  "table": {
   "columns": [
    "parameter",
    "value or range",
    "source"
   ],
   "rows": [
    [
     "Cleaver prop speed",
     "above ~50 kn",
     "ITU (Takinaci)"
    ],
    [
     "Draft",
     "can be ~half a prop diameter",
     "ITU (Takinaci)"
    ],
    [
     "RC shaft height",
     "3/8-1/2 in above keel",
     "Model Gas Boats forum"
    ],
    [
     "RC prop example",
     "44 mm dia, 1.4 pitch ratio",
     "SV Design (Stealthwake)"
    ]
   ]
  }
 },
 "sheet_text": "Surface drive (surface-piercing propeller) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/surface-piercing-drive/  (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- A surface drive runs the propeller only partly submerged near the water surface. Removing shafts, struts and hubs from the water cuts appendage drag, and the prop can be large and lightly loaded; ventilation replaces cavitation (ITU lecture).\n- Drawbacks are vibration, poor reverse, difficult turns, harder set-up and poor efficiency at low rpm. Cleaver props suit speeds above ~50 knots (ITU).\n- RC 'stinger' drives position the prop similarly; racers report no difference in hull behaviour if the prop sits in the same place (Model Gas Boats forum).\n- The file is a reference example built by Xem Studio from the numbers above (44 mm x 1.4 pitch ratio RC mono prop (SV Design).). Sizes the sources do not fix are illustrative; scale the example to your own vehicle.\n\nparameter  value or range  source\nCleaver prop speed  above ~50 kn  ITU (Takinaci)\nDraft  can be ~half a prop diameter  ITU (Takinaci)\nRC shaft height  3/8-1/2 in above keel  Model Gas Boats forum\nRC prop example  44 mm dia, 1.4 pitch ratio  SV Design (Stealthwake)\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Istanbul Technical University (A. C. Takinaci): Advanced Propulsion Systems, Week 14: Surface Piercing Propellers — web — Publisher's page; dimensions are facts — https://web.itu.edu.tr/takinaci/dersler/advpropsys/Week_14/SurfacePiercingPropellers.pdf\n- Model Gas Boats forum: Stinger drive versus strut support set up — web — Publisher's page; dimensions are facts — https://modelgasboats.com/forum/13-ask-the-editors-discuss-articles-general-boat-questions/16025-stinger-drive-versus-strut-support-set-up?start=0\n- SV Design: Pro Boat Stealthwake upgrades info (Feb 2022) — web — Publisher's page; dimensions are facts — https://myplace.frontier.com/~sv_design/Pro%20Boat%20Stealthwakes%20Upgrades%20Info%20SVC_Feb-2022.pdf\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/surface-piercing-drive/index.json\nAPI: https://xemstudio.com/api/geometry?object=surface-piercing-drive\n",
 "sources": [
  {
   "publisher": "Istanbul Technical University (A. C. Takinaci)",
   "title": "Advanced Propulsion Systems, Week 14: Surface Piercing Propellers",
   "url": "https://web.itu.edu.tr/takinaci/dersler/advpropsys/Week_14/SurfacePiercingPropellers.pdf",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Model Gas Boats forum",
   "title": "Stinger drive versus strut support set up",
   "url": "https://modelgasboats.com/forum/13-ask-the-editors-discuss-articles-general-boat-questions/16025-stinger-drive-versus-strut-support-set-up?start=0",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "SV Design",
   "title": "Pro Boat Stealthwake upgrades info (Feb 2022)",
   "url": "https://myplace.frontier.com/~sv_design/Pro%20Boat%20Stealthwakes%20Upgrades%20Info%20SVC_Feb-2022.pdf",
   "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": "Is it more efficient?",
   "a": "At high speed yes; at low rpm no (ITU)."
  }
 ],
 "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": "surface-piercing-drive-propeller",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/surface-piercing-drive/surface-piercing-drive-propeller.step",
   "stl": "https://xemstudio.com/files/hardware/surface-piercing-drive/surface-piercing-drive-propeller.stl",
   "note": "1.73×2.43 in propeller, 2 blades: each section set at the geometric pitch angle atan(P / 2πr); chord and section illustrative"
  }
 ],
 "markdown": "https://xemstudio.com/objects/surface-piercing-drive/index.md"
}