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Trim tabs

How do trim tabs work and what size do I need? · Standard part · basis: Design rules and figures from the cited sources; example geometry by Xem Studio

Also called: boat trim tabs, rc trim tabs, trim tab size, trim tab angle, bow down trim, trim plates, hydraulic trim tabs, trim tab sizing

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

sizes
3 in table

Notes

  • Trim tabs are adjustable plates at the transom that push the stern up and the bow down, and can correct list (West Marine).
  • West Marine's rule of thumb: at least 1 in of tab span per foot of boat length. On an RC mono, one builder runs tabs about 1-3 mm below the hull bottom (SV Design).
  • The file is a reference example built by Xem Studio from the numbers above (1 x 1.5 in RC tab (SV Design); deflection illustrative.). Sizes the sources do not fix are illustrative; scale the example to your own vehicle.

Trim tabs size chart

parametervalue or rangesource
Span rule>=1 in per ft of boat lengthWest Marine
RC tab drop1-3 mm below bottomSV Design (Stealthwake)
RC tab size example1 x 1.5 in metal tabsSV Design (Stealthwake)

Where the files are

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

West MarineSelecting and Installing Trim TabswebPublisher's page; dimensions are facts
SV DesignPro Boat Stealthwake upgrades info (Feb 2022)webPublisher'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

trim-tabs-tabHinged plate 38 × 25 mm deflected 5°STEP · STL
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Plain text: sheet.txt · JSON: /api/geometry?object=trim-tabs

Trim tabs, isometric render of a generated part
Render of trim-tabs-tab from the free STEP; not to scale.

Fits with

Deep-V hull, isometric render of a generated part
Deep-V hull6 sizes★ 1 file
Modified-V (semi-V) hull, isometric render of a generated part
Modified-V (semi-V) hull2 sizes★ 1 file
Flat-bottom hull, isometric render of a generated part
Flat-bottom hull1 sizes★ 1 file
Cathedral (tri-hull), isometric render of a generated part
Cathedral (tri-hull)2 sizes★ 1 file
Tunnel hull (tunnel catamaran), isometric render of a generated part
Tunnel hull (tunnel catamaran)4 sizes★ 1 file
Three-point hydroplane, isometric render of a generated part
Three-point hydroplane4 sizes★ 1 file

Questions

How wide?

At least 1 in per foot of length (West Marine).