Corner Fittings

Corner Fittings & Rings

Comprehensive specifications for rings, grommets, and fittings used across Mainsails, Headsails, and Downwind sails.

Primary Corner & Reefing Hardware Types

1. O-Ring: Omni-directional load distribution; versatile standard ring for general corner connections and shackles.
2. O-Ring with Bar: Internal crossbar locks webbing securely in place while leaving the outer ring free for sheets (standard for Clew).
3. Butterfly Ring: Dual-axis bars securely anchor intersecting high-load webbing from both Leech and Foot (standard for high-load Clews).
4. Press Ring (Grommet / Super Ring): Pressed directly through reinforced cloth layers without external webbing (used for reef points, cringles and smaller sails).
5. Webbing Loop (1” or 1.5”): Soft fabric loop with no metal hardware, available in 1” and 1.5” to match deck fittings and furlers (lightweight and scratch-free).

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1. Pressed Rings (Grommets / Eyelets)

Used for standard clews, tacks, and reef points. “Spur” grommets are used for high-load applications to prevent pull-out.

Material Specifications

• Standard: Nickel-Plated Brass (Corrosion resistant, good ductility).
• Racing/Heavy Duty: 316 Stainless Steel (Higher yield strength, harder to set).

Sizing Table

Size Code	Inner Ø (ID)	Flange OD	Max Fabric Thickness	Layers (Sunbrella)	Application
#0	1/4” (6.4 mm)	14-17 mm	1.2 - 2.4 mm	3-4	Small leech lines, luff eyes
#1	5/16” (7.9 mm)	15-20 mm	1.2 - 3.6 mm	3-6	Reef lines, small boat corners
#2	3/8” (9.5 mm)	19-21 mm	2.4 - 7.3 mm	4-12	Standard reef points
#3	7/16” (11.1 mm)	24-25 mm	1.5 - 5.5 mm	3-9	Medium boat corners, head/tack
#5	5/8” (15.9 mm)	28-32 mm	2.4 - 6.7 mm	4-11	Large boat corners, heavy reef

Detailed specifications based on industry standards (e.g., Stimpson, Bainbridge).

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2. Stainless Steel Rings (O-Rings & D-Rings)

Welded 316 Stainless Steel rings for structural strapping (webbing) attachment. Essential for high-load corners where pressed rings might fail or damage the sail.

Common O-Rings (Metric)

Dimension (OD x Wire Ø)	Working Load (Ref)	Application
25 x 6 mm	Moderate	Control line ends, leech lines
31 x 6 mm	Medium	General connection, clew straps
33 x 8 mm	Heavy	Staysail tack, structural sheets
40 x 6 mm	Light/Wide	Wide webbing straps, low load
38 x 10 mm	Extra Heavy	Main clew, tack anchorage
40 x 8 mm	Balanced	Heavy duty webbing loops

Bainbridge Structural Rings (SR / B-Series)

Specialized heavy-duty rings for offshore and racing sails.

Model	Size / Desc	Material	Application
SR-35	35mm ID	316 SS	Structural strapping
SR-45	45mm ID	316 SS	Large reinforcements
SR-55	55mm ID	316 SS	Mega yacht corners
B225	51 x 11 mm	316 SS	Heavy stamped ring (Main Clew)
B226	63 x 12 mm	316 SS	X-Large load corner
B218	76 x 15 mm	316 SS	Offshore racing spec

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3. External Rings (ER) & Thimbles

Used for specific hardware interfaces or batten tensioners.

Series	Sizes (mm)	Description	Usage
ER Series	14, 20, 25, 30	External Rings	Batten box tensioners, small external lashings
Thimbles	Various	Teardrop shape	Spliced wire/rope eyes, prevent chafing
B-125	75 x 11 mm	Standard Thimble	Standard sail thimble
B-122	105 x 10 mm	Heavy Thimble	Heavy duty load point

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4. Low Friction Rings (Hardware-Free)

Modern replacement for blocks in static or low-movement applications (Cascades, Barber haulers).

Harken Lead Rings

Material: 6061-T6 Aluminum, Hard Lube-anodized (PTFE impregnated).

Model	ID (mm)	Groove Width	Max Line Ø	Application
3269	8 mm	5 mm	5 mm	Leech lines, small control lines
3270	10 mm	6 mm	6 mm	In-haulers, reefing deflectors
3271	14 mm	10 mm	10 mm	Backstay cascades, heavy control
3272	20 mm	14 mm	14 mm	Runners, primary sheet leads
3273	28 mm	19 mm	19 mm	Superyacht / Grand Prix systems

Note: Friction increases with angle. Use where line movement is minimal or loaded intermittently.

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5. Webbing Anchors & Cleats

Component	Dimensions	Material	Application
B-250 Cleat	Large Base	Cast Al/Bronze	Heavy duty leech line cleating
GRH Ring	38 x 9 mm	Heavy Grommet	Reinforced structural pass-through

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