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Cathedral (tri-hull)

What is a cathedral or tri-hull boat? · Standard part · basis: Design rules and figures from the cited sources; example geometry by Xem Studio

Also called: cathedral hull, tri hull, tri-hull boat, trihull, three sponson hull, cathedral boat, tri hull pros cons, deck boat hull, airslot hull

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

sizes
2 in table

Notes

  • A tri-hull is a V hull with sponsons built into the bow, so it looks like three hulls forward but is one solid hull aft (Boatsetter).
  • The sponsons add buoyancy, width and stability, making a good fishing and deck-boat platform, but the triple bow pounds in chop for a rough, wet ride (Boatsetter).
  • Richard Cole designed the first tri-hull in 1958 at Thunderbird Boats; most builders moved to deep-V hulls in the 1980s (Boatsetter).
  • Used on: Wellcraft Airslot, Thunderbird tri-hulls.
  • 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.

Cathedral size chart

parametervalue or rangesource
First design1958 (Richard Cole, Thunderbird Boats)Boatsetter
Current usedeck boats; fishing boats under 18 ftBoatsetter

Where the files are

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

BoatsetterWhat is a tri-hull boat?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

cathedral-tri-hull-hullcathedral hull, 585 × 181 mm, deadrise 18° (sections illustrative, scale to your boat)STEP · STL
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Plain text: sheet.txt · JSON: /api/geometry?object=cathedral-tri-hull

Cathedral (tri-hull), isometric render of a generated part
Render of cathedral-tri-hull-hull 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
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
Stepped hull, isometric render of a generated part
Stepped hull3 sizes★ 1 file

Questions

Why did they fall out of favour?

They pound in chop; composites let builders switch to deep-V hulls (Boatsetter).