Xem Studiomeasured geometryLibrary › Boat design › Sailboat appendages ·
Skeg-hung rudder
Why use a skeg-hung rudder instead of a spade? · Standard part · basis: Design rules and figures from the cited sources; example geometry by Xem Studio
Also called: skeg hung rudder, skeg rudder, partial skeg, rudder skeg, cruising rudder, skeg vs spade, full skeg rudder, skeg rudder stall
Exact dimensions. True size, with no printing tolerance added.
- sizes
- 2 in table
Notes
- A skeg ahead of the rudder supports a lower bearing, protects the blade and helps tracking; because the skeg sees a lower angle of attack, the combination stalls later than a spade (Good Old Boat).
- A full skeg leaves no balance area, so helm loads get high on big boats; Perry's compromise is a half-depth partial skeg.
- The file is a reference example built by Xem Studio from the numbers above (Illustrative.). Sizes the sources do not fix are illustrative; scale the example to your own vehicle.
Skeg-hung rudder size chart
| parameter | value or range | source |
|---|---|---|
| Partial skeg | about half rudder depth (Perry) | Good Old Boat |
| Upwind weather helm optimum | 2-4 deg | Good Old Boat |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Good Old Boat | The rudiments of rudders | web | Publisher's page; dimensions are facts |
Free files
★ Free files 1 parts. Xem Studio design: free to use, print and sell things from; not to be republished as files. Xem Studio Design License. index.json
https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.Plain text: sheet.txt · JSON: /api/geometry?object=skeg-hung-rudder
Fits with
Questions
Why later stall?
The skeg's leading edge sees a lower angle of attack (Good Old Boat).