Lewmar 50mm Synchro Block - Single
Lewmar 50mm Synchro Block - Single Product Description
Discover the pinnacle of performance in marine hardware with the Lewmar 50mm Synchro Block Single. Designed for sailors who demand precision and reliability, this compact powerhouse transforms how you manage sheets and control lines on the water. Whether you're fine-tuning your mainsail on a racing dinghy or handling loads on a cruiser, its innovative engineering delivers smoother operation and unmatched efficiency.
Engineered for Seamless Power Transfer
What sets the Synchro Block apart is its thoughtful design that minimizes friction and maximizes speed. The optimized sheave geometry works in harmony with a free-spinning bearing and self-aligning head, boosting efficiency by up to 40% compared to standard blocks. This means less effort to trim sails, quicker response times during maneuvers, and reduced rope wear over long races or passages.
Sailors appreciate how every element syncs perfectly with rope movement. The result? Effortless power from deck to sail, even under high tension. Ideal for mainsheet systems where every ounce of performance counts.
Robust Construction for Demanding Conditions
- Stainless Steel Strap: Enhances strength and durability, standing up to saltwater corrosion and heavy use for extended service life.
- Stiff Glass Fiber Reinforced Cheeks: Rigid structure prevents lines from binding or wedging, ensuring smooth rotation even with angled pulls.
- Versatile Swivel Shackle: Tool-free sliding mechanism lets you switch between swiveling and fixed modes effortlessly, adapting to any mounting scenario.
Finished in sleek black, it blends functionality with a modern aesthetic that complements any boat's deck layout. The glass fiber reinforced cheeks not only add stiffness but also keep weight down at just 2.36 ounces, making it perfect for performance-oriented setups.
Technical Specifications at a Glance
- Type: Single block with swivel head
- Sheave Diameter: 50mm for optimal line handling
- Maximum Line Diameter: 10mm (0.39 inches)
- Working Load Limit: 990 pounds – reliable for most recreational and competitive applications
- Pulley Count: 1
- Cleat: None (clean design for free-running lines)
- Ratchet: Non-ratcheting, suitable for any direction
- Becket: No
- Mounting: Swivel shackle for flexible installation
- Material: Glass fiber reinforced cheeks with stainless steel strap
These specs make it a go-to choice for vangs, travelers, and control lines where low friction and high strength intersect.
Real-World Applications for Sailors
On the race course, the Synchro Block shines in mainsheet systems, allowing crews to make rapid adjustments without fighting friction. Cruisers value its low maintenance and rope-friendly design during extended voyages. Mount it on spinnaker sheets, outhauls, or cunningham tackles for consistent performance.
Pro tip: Pair it with high-quality low-stretch line to fully leverage its efficiency gains. In choppy conditions, the self-aligning head keeps everything tracking smoothly, reducing chafe and extending gear life.
Effortless Maintenance and Longevity
Keeping your Synchro Block in top shape is straightforward. Rinse with fresh water after each sail to remove salt buildup, and inspect the bearing periodically for smooth rotation. The open design allows quick access without disassembly tools. Over time, this simple routine ensures it performs like new, season after season.
Unlike cheaper alternatives, its premium materials resist UV degradation and fatigue, making it a smart investment for serious sailors.
Why Synchro Stands Above the Rest
In a sea of blocks, Lewmar's Synchro series excels through science-backed innovation. Budget options often compromise on bearing quality or cheek stiffness, leading to higher friction and premature wear. This 50mm single delivers race-proven tech in a versatile package – efficient, lightweight, and built to last. Elevate your rigging setup and feel the difference in every tack and gybe.
Frequently Asked Questions
What makes the Lewmar 50mm Synchro Block more efficient than standard blocks?
Its scientifically optimized geometry, free-spinning bearing, and self-aligning head reduce friction by up to 40%, providing smoother power transfer and less rope wear.
What line sizes is the Lewmar 50mm Synchro Block compatible with?
It handles lines up to 10mm (0.39 inches) in diameter, ideal for most sailing applications.
Can the swivel on this block be locked in place?
Yes, the innovative tool-free mechanism allows easy switching between swiveling and fixed modes for versatile mounting.
What is the working load limit of the Synchro 50mm Single Block?
It supports a working load limit of 990 pounds, suitable for mainsheets, vangs, and control lines.
How do I maintain the Lewmar Synchro Block for longevity?
Rinse with fresh water after use, inspect bearings regularly, and avoid prolonged exposure to harsh chemicals. Its design supports easy, tool-free cleaning.
Is this block suitable for racing sailboats?
Absolutely – its low-friction design and lightweight construction (2.36oz) make it a favorite for competitive racing where speed and efficiency matter.
Does the Synchro Block have a ratchet or cleat?
No, it features a non-ratcheting design with no integral cleat, focusing on free-running efficiency for sheets and controls.
Lewmar’s Synchro blocks are engineered for speed, efficiency and superior handling. We use a combination of scientifically optimized block geometry, a Free-Spin bearing and self-aligning head to reduce friction and increase efficiency by up to 40 Percent over budget blocks on mainsheet systems. Each component is perfectly synchronized with the movement of the rope, providing you with an easier, smoother transfer of power from deck to sail and less wear on your rope.
Lewmar 29925001BK Attributes
- Type: Single Block
- Number Of Pulley: 1
- Working Load Limit: 990 Pound
- Line Diameter: 10 Millimeter
- Sheave Diameter: 50 Millimeter
- Cleat Type: No Integral Cleat
- Ratchet And Direction: Non Ratcheting Any Direction
- With Becket: No
- Color: Black
- Material: Glass Fiber Reinforced Cheek
- Mounting Type: Swivel Shackle Mount
Lewmar 29925001BK Features & Benefits
- Stainless Steel Strap For Improved Strength And Longer Service Life
- Stiff Glass Fiber Reinforced Cheeks To Prevent Lines From Wedging
- Simple Switch To Change From Swiveling To Fixed Shackle
- Easy Maintenance
- Limited 3 Year Warranty
Lewmar 29925001BK Warranties
50mm Synchro Block - Single
Lewmar's Synchro Blocks are engineered for speed, efficiency, and superior handling. Using a combination of scientifically optimized block geometry, a Free-Spin bearing, and a self-aligning head to reduce friction and increase efficiency by up to 40%, over budget blocks on mainsheet systems.
Each component is perfectly synchronized with the movement of the rope, providing you with an easier, smoother transfer of power from deck to sail and less wear on your rope.
Features:
- Stainless steel strap for improved strength and longer service life
- Stiff glass fiber reinforced cheeks to prevent lines from wedging
- Innovative design with “tool-free” sliding swivel locking mechanism
Technical Specifications:
- Working Load Limit - 990lb
- Weight - 2.36oz
- Maximum Line Size - .39" (10mm)
*Sold as an Individual
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Lewmar 50mm Synchro Block - Single Technical Specifications
| Type: | |
|---|---|
| Vendor: |
Lewmar |
| Weight: |
0.4 lb |
Lewmar 50mm Synchro Block - Single User Reviews
Lewmar 50mm Synchro Block - Single Shipping & Return
| Shipping Weight: |
0.4 lb |
|---|---|
| Box Sizes: |
1.00 (h) x 2.00 (w) x 4.00 (l) |
| Cubic Feet: |
8.0 |
| Returnable: |
Yes |
| USPS First Class: |
Yes |
For detailed shipping policy please check our Shipping Policy and you can find our Return and Refund Policy here.




