Reef Systems Overview
Reef Systems
Section titled “Reef Systems”Mainsail reefing configurations and hardware specifications.
System Types
Section titled “System Types”Slab Reefing (Jiffy Reef)
Section titled “Slab Reefing (Jiffy Reef)”| Property | Specification |
|---|---|
| Mechanism | Reef points with cringle/horn |
| Reef positions | Typically 1-3 reefs |
| Reduction per reef | 15-25% area |
| Complexity | Low-moderate |
| Reliability | Very high |
Components:
- Reef cringle (luff)
- Reef cringle (leech)
- Reef lines
- Reef cheek blocks
- Cleat or winch
In-Mast Furling
Section titled “In-Mast Furling”| Property | Specification |
|---|---|
| Mechanism | Vertical roll into hollow mast |
| Reduction | Continuously variable |
| Complexity | High (mast integration) |
| Sail shape | Compromised (flat cut required) |
Requirements:
- Hollow mast section
- Furling gear (manual or electric)
- Flat-cut sail (no roach)
- Vertical battens only
Furler options:
| Brand | Series | Boat Size |
|---|---|---|
| Selden | FurlBoom | 30-50ft |
| Schaefer | In-Mast | 35-55ft |
| Profurl | Inside | 28-45ft |
In-Boom Furling
Section titled “In-Boom Furling”| Property | Specification |
|---|---|
| Mechanism | Horizontal roll into boom |
| Reduction | Continuously variable |
| Sail shape | Full roach possible |
| Complexity | High (boom integration) |
Requirements:
- Specialized boom with mandrel
- Insertable luff rope (not bolt rope)
- Electric or hydraulic drive (recommended)
- Batten compatibility check
Boom options:
| Brand | Series | Boat Size |
|---|---|---|
| Leisure Furl | System | 35-60ft |
| Selden | FurlBoom | 35-55ft |
| Z-Spars | In-Boom | 38-65ft |
Slab Reef Hardware
Section titled “Slab Reef Hardware”Reef Cringles
Section titled “Reef Cringles”| Type | Application |
|---|---|
| Pressed ring | Standard construction |
| Heavy-gauge ring | Offshore/heavy loads |
| Webbing loop | Ultra-light racing |
Reef Line Lead
Section titled “Reef Line Lead”| Configuration | Description |
|---|---|
| External | Lines run on boom exterior |
| Internal | Lines run inside boom |
| Single-line | Luff + leech controlled by one line |
Reef Horn/Hook
Section titled “Reef Horn/Hook”| Location | Hardware |
|---|---|
| Gooseneck | Reef horn (stainless) |
| Boom | Reef hook or ring |
Reef Position Specifications
Section titled “Reef Position Specifications”Reef Heights
Section titled “Reef Heights”Critical dimension determining sail area reduction. Measured from boom to reef point.
| Reef Position | Height from Foot (% of P) | Typical Measurement | Area Reduction | Wind Range |
|---|---|---|---|---|
| First Reef | 15-20% | Variable by boat | 15-20% | 15-20 knots |
| Second Reef | 30-35% | Variable by boat | 30-40% cumulative | 20-30 knots |
| Third Reef (Storm) | 45-50% | Variable by boat | 50-60% cumulative | 30+ knots |
P = Luff length (mainsail hoist)
Important: Reef heights are customized per sail based on:
- Boat size and displacement
- Sailing program (coastal, offshore, racing)
- Rig configuration
- Owner preference
Reef Tack Configuration
Section titled “Reef Tack Configuration”Reef Luff Finishing Options
Section titled “Reef Luff Finishing Options”Hardware installed at the luff end of each reef to attach to reef horn/hook.
| Code | Name | Description | Components | Best For |
|---|---|---|---|---|
| RTPR | Press Ring | Simple pressed stainless ring | Stainless steel grommet | Budget cruising, traditional |
| RTOR | Webbed O-Ring | Ring reinforced with webbing | SS ring + webbing reinforcement | Standard cruising |
| RTDB | Dog Bones / Hoppy Rings | Multiple small rings on webbing (min 3” webbing) | 2-3 small rings + wide webbing | High-load distribution |
| RTLFR | Reef Luff Low Friction Ring | Dyneema low-friction ring | Soft ring (Dyneema/Spectra) | Racing, reduced weight |
| RTPRL | Press with Webbing Loop | Ring with integrated webbing loop | SS ring + sewn loop | Quick attachment |
| RTWL | Webbing Loop | Webbing-only loop (no ring) | Heavy-duty webbing | Ultra-light racing |
| RTWH | Reef Hook / Shackle | Hook or soft shackle attachment | Shackle or hook fitting | Quick-release systems |
| RTSB | Reef Block | Small block for 2:1 mechanical advantage | Micro block + ring | Single-line reefing |
| RTWL-H | Webbing Loop w/Handle | Webbing loop with handle (min 3” below, over 40’4” loop) | Webbing + handle | Large boats 40ft+, manual handling |
| RTSSK | Soft Shackle | Dyneema soft shackle | Soft shackle (Dyneema) | Racing, adjustable systems |
Reef Clew Configuration
Section titled “Reef Clew Configuration”Reef Leech Finishing Options
Section titled “Reef Leech Finishing Options”Hardware installed at the leech end of each reef for outhaul attachment.
| Code | Name | Description | Components | Best For |
|---|---|---|---|---|
| RCPR | Press Ring | Simple pressed stainless ring | Stainless steel grommet | Budget cruising |
| RCOR | Webbed O-Ring | Ring reinforced with webbing | SS ring + webbing | Standard cruising |
| RCWL | Webbing Loop | Webbing loop (no ring) | Heavy-duty webbing | Weight-sensitive applications |
| RCLFR | Low Friction Ring on Sail | Soft ring attached to sail | Dyneema ring + lashing | Racing, in-leech position |
| RCLFR-OL | Low Friction Ring Out of Leech | Soft ring extending beyond leech | Dyneema ring + webbing tail | Offshore, easier handling |
| RCSB | Reef Block | Small cheek block for reef line | Micro block | Single-line reefing systems |
Reef Diamond (Patch) Specifications
Section titled “Reef Diamond (Patch) Specifications”Reef Reinforcement Patches
Section titled “Reef Reinforcement Patches”Reinforcement around reef cringle to distribute loads across sailcloth.
Standard Patch Sizes (Default)
Section titled “Standard Patch Sizes (Default)”| Reef Position | Reef Eyelet Size (Ring ID) | Reef Patch Size (Diameter) | Reinforcement Layers |
|---|---|---|---|
| First Reef | #5 (5/8” / 16mm) | 8-10” (200-250mm) | 3-4 layers |
| Second Reef | #5 (5/8” / 16mm) | 8-10” (200-250mm) | 3-4 layers |
| Third Reef | #4 or #5 | 10-12” (250-300mm) | 4-5 layers (storm reinforcement) |
Note: Patch sizes increase for larger boats or offshore specifications.
Reef Ring Options
Section titled “Reef Ring Options”Two primary methods for creating reef reinforcement:
| Type | Description | Pros | Cons | Application |
|---|---|---|---|---|
| SR (Spur Ring) | Metal grommet pressed through reinforcement layers | Very durable, traditional | Heavier, potential chafe point | Standard cruising, offshore |
| Webbing | Heavy-duty webbing loop sewn through patches | Lighter, no hard edges | Less traditional, requires larger patches | Racing, weight-conscious builds |
SR Ring Specifications:
- Material: Stainless steel (304 or 316)
- Common sizes: #4 (1/2”), #5 (5/8”), #6 (3/4”)
- Finish: Polished or satin
Webbing Specifications:
- Material: Polyester or Dyneema webbing
- Width: 1-2” (25-50mm)
- Breaking strength: 3,000-6,000 lbs
Reef Orientation (Port vs Starboard)
Section titled “Reef Orientation (Port vs Starboard)”Reef Side Configuration
Section titled “Reef Side Configuration”Reefs are installed with orientation based on rigging preference.
| Configuration | Description | Typical Setup |
|---|---|---|
| Starboard (STBD) | Reef lines led to starboard side | Most common for single-handed sailing (starboard tack favored) |
| Port | Reef lines led to port side | Less common, specific rig configurations |
| Dual | Reef lines on both sides | Offshore cruising, redundancy |
Practical Consideration:
- Starboard orientation is standard because most boats spend more time on starboard tack
- Reef tack hardware is positioned for line routing to the designated side
- Clew hardware matches tack side for consistent tensioning
Furling System Reef Compatibility
Section titled “Furling System Reef Compatibility”In-Boom Furling
Section titled “In-Boom Furling”Reef Point Installation: Reef points are sewn directly onto the sail.
| Feature | Specification |
|---|---|
| Reef positions | 1-3 traditional reef points available |
| Hardware | Standard reef cringles (tack + clew) |
| Functionality | Allows choice between furling OR slab reefing |
| Best for | Cruising boats wanting backup reefing options |
Important: In-boom furling sails CAN have reef points as a backup system in case of furling gear failure.
In-Mast Furling
Section titled “In-Mast Furling”Reef Capability: Continuously variable, infinitely adjustable.
| Feature | Specification |
|---|---|
| Reef positions | No fixed reef points |
| Reduction method | Roll sail into mast to any desired position |
| Precision | Furl to exact percentage needed |
| Hardware | No reef cringles required |
Advantages:
- Furl to any percentage of sail area (10%, 25%, 50%, etc.)
- No need to go forward to the mast
- Instant adjustment from cockpit
Limitations:
- Sail shape degrades when partially furled
- No traditional reef reinforcement
- Requires flat-cut sail with vertical battens only
Reinforcement Requirements
Section titled “Reinforcement Requirements”Load Path Reinforcement
Section titled “Load Path Reinforcement”| Feature | Material |
|---|---|
| Cringle to clew | Webbing tape |
| Cringle to tack | Webbing tape |
| Reef point patches | Matching sailcloth |
Furling System Specifications
Section titled “Furling System Specifications”In-Mast Requirements
Section titled “In-Mast Requirements”| Parameter | Specification |
|---|---|
| Luff curve | Minimal (flat entry) |
| Roach | None (straight leech) |
| Battens | Vertical only |
| Headboard | Integrated with furler |
In-Boom Requirements
Section titled “In-Boom Requirements”| Parameter | Specification |
|---|---|
| Luff rope | Insertable (not bolt rope) |
| Foot curve | Match mandrel diameter |
| Battens | Full-length OR none |
| Clew angle | Match boom angle |