Library › Boat design › Hull types ·

Turn fins (RC boats)

Name: Turn fins (RC boats) dimension sheet
Creator: Xem Studio
License: https://creativecommons.org/licenses/by/4.0/

What are turn fins on RC boats for? · Standard part · basis: Design rules and figures from the cited sources; example geometry by Xem Studio

Also called: turn fin, rc boat turn fins, sponson turn fin, hydro turn fin, turn fin angle, mono turn fin, rc boat fins, turning fin

Exact dimensions. True size, with no printing tolerance added.

sizes: 2 in table

Notes

Turn fins are small vertical blades near the chine that give the hull grip in turns. On a deep-V mono a racer places a right-turn fin as close to the chine line as possible at 90 deg to the V surface (Model Gas Boats forum).
On hydros, forward tilt makes the boat track left and lifts the starboard sponson; backward tilt does the opposite (Model Gas Boats).

Turn fins size chart

parameter	value or range	source
Mono fin placement	near chine, 90 deg to V surface	Model Gas Boats forum
Hydro fin forward tilt	tracks left, lifts starboard sponson	Model Gas Boats

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

Model Gas Boats forum	Need help setting up a mono for the first time	web	Publisher's page; dimensions are facts
Model Gas Boats	Some tips on setting up a hydroplane hull	web	Publisher's page; dimensions are facts

Xem scan

File coming

No downloadable true-size file yet: the published figures do not fix the whole shape, and Xem never guesses a number. A measured scan is planned; request it and it moves up.

Let your AI pull this. Add 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.

Set it up →

Plain text: sheet.txt · JSON: /api/geometry?object=turn-fins

Schematic, not to scale.