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Lewmar 29925004BK 50mm Synchro Single Block with Becket

Manufacturer

Lewmar

<h3>About Lewmar: A Legacy of Marine Innovation Since 1946</h3><p><strong>Lewmar</strong> traces its roots to 1946, when <a href="/7429-lewmar">the brand</a> was founded by sailing enthusiasts Len Lewery and Leslie Marsh. What began as a modest workshop producing dinghy fittings has grown, over more than seven decades, into one of the most respected names in global marine equipment manufacturing. Today, Lewmar is part of the Lippert family of brands — a leading international supplier serving the marine, RV, and related industries — while retaining the engineering heritage and craftsmanship that made its reputation.</p><p>Headquartered in Havant, Hampshire, in the United Kingdom, Lewmar designs and manufactures its products primarily at its UK production facility. That combination of British engineering tradition and modern manufacturing technology is central to what sets Lewmar apart. The brand has earned multiple Queen's Awards and a pair of prestigious DAME Awards — including recognition for its revolutionary Ocean Block and the innovative OneTouch winch handle — underlining its consistent commitment to pushing marine technology forward.</p><h3>A Complete Solution for Every Vessel</h3><p>One of Lewmar's defining strengths is the sheer breadth of its catalog. Whether you're outfitting a compact day fishing boat or equipping a luxury mega-yacht, the brand offers a solution designed to fit. Its core product lines span <a href="/m/7429/c/windlasses">windlasses</a>, <a href="/m/7429/c/winches">winches</a>, <a href="/m/7429/c/hatches">hatches and portlights</a>, <a href="/m/7429/c/thrusters">bow and stern thrusters</a>, and a comprehensive range of <a href="/m/7429/c/anchoring">anchoring systems</a> — all engineered to perform reliably in demanding marine environments.</p><p>Lewmar <a href="/m/7429/c/windlasses">windlasses</a> have become a benchmark product for the brand, with models like the V700 Series, Pro Series 700, and ProFish 1000 delivering robust anchor deployment and retrieval performance for both recreational and commercial vessels. Their <a href="/m/7429/c/winches">winch lineup</a> — available in manual and electric variants — includes the acclaimed EVO self-tailing winch range, designed for sailors who demand the highest levels of sail-handling efficiency. The Wavegrip jaw system, an early Lewmar innovation, helped define the modern self-tailing winch market.</p><p>Above deck, Lewmar <a href="/m/7429/c/hatches">hatches and portlights</a> are engineered for watertight integrity without sacrificing ventilation or aesthetic appeal. Low-profile and Ocean hatch designs suit everything from sleek performance cruisers to long-haul bluewater sailboats. Below the waterline (or rather, in the engine room and at the helm), Lewmar's <a href="/m/7429/c/thrusters">bow and stern thrusters</a> — including the Gen 2 series — provide smooth, powerful maneuvering assistance, making tight berths and marina approaches manageable even in challenging conditions.</p><p>The brand's <a href="/m/7429/c/anchoring">anchoring range</a> includes the well-regarded Delta, Claw, and DTX anchor designs. The Claw anchor, inspired by hardware used to secure North Sea oil rigs, is renowned for its reliable hold across a wide variety of seabed types and its easy stowage. The DTX bridges the performance gap between galvanized and stainless-steel options, offering a high-specification anchor at a more accessible price point.</p><h3>Racing Pedigree and Real-World Reliability</h3><p>Lewmar's products have been tested in some of the world's most demanding sailing environments. Lewmar winch systems appeared on both competing vessels at the historic 1983 America's Cup, and Lewmar hardware was fitted to Gipsy Moth IV when Francis Chichester completed his legendary solo circumnavigation. This racing and expedition heritage isn't just history — it directly informs the engineering standards that Lewmar applies to every product in its lineup today, from entry-level windlass kits to carbon-fiber winches built for superyachts.</p><p>For sailors, powerboat owners, and professional boat builders alike, Lewmar represents a trusted partner for on-deck hardware, anchoring solutions, and boat-handling systems that perform when it matters most.</p>

Part Number

29925004BK
06/23/2036 5:15 PM
Sale Price

$25.42

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Product Details

The Lewmar 29925004BK is a 50mm Synchro Single Block with Becket, engineered for sailors who demand racing-level performance at a cruising-friendly price point. Part of Lewmar's acclaimed Synchro Block series, this block represents a ground-up rethink of traditional block design to maximize speed, efficiency, and ease of handling in running rigging applications.

At the heart of the Synchro design is a combination of scientifically optimized block geometry, a Free-Spin high-density bearing, and a self-aligning swivel head that work together to reduce friction and improve system efficiency by up to 40% compared to conventional mainsheet blocks. Every component is synchronized with the movement of the rope, delivering a smoother transfer of power from deck to sail while minimizing wear on both the line and the block itself.

Key Features:

  • Free-Spin bearing: High-density, self-lubricating bearing reduces axle diameter for superior mechanical efficiency
  • Self-aligning swivel head: Innovative sliding lock mechanism allows selection between full 360° free rotation or fixed positions at 0° or 90° to the sheave axle
  • 30° rotational float: Both fixed positions provide 30° of float so the block can self-align within the system
  • Larger sheave diameter (50mm): Minimizes rope friction and works well with lines up to 3/8" (10mm)
  • Stainless steel straps: Improved strength and extended service life
  • Glass fiber reinforced cheeks: Stiff construction prevents lines from wedging
  • Becket included: Provides an anchor point for the standing end of a purchase system
  • Black finish (BK): Clean, low-profile appearance suited to modern sailboat hardware

The Lewmar 29925004BK is well-suited for mainsheet systems, boom vangs, halyard tuning, and other purchase systems where friction reduction and smooth rope travel are critical. The addition of the becket makes this block ideal as the lower block in a multi-part tackle arrangement. A tool-free sliding swivel locking mechanism makes adjustments quick and easy on the water.

Products specifications

Type

Single

Diameter

3/8 Inch or 10 mm

Mount Type

Swivel Shackle

Weight

0.17

Ball Bearings

Plain Bearings

Becket

Becket

Direction

Any

Integral Cleat

No Integral Cleat

Ratchet

Non Ratcheting

Safe Working Load

990 Pounds

Sheave Diameter

50 mm

shopping from thmotorsports was an easy, enjoyable process. The items came fairly quick and were exactly what the product looked like while shopping.

Fast shipping, item as described.

Shipped quickly. Easy to order

As always great experience. I have ordered from this place in the past and have never had a bad experience. Much appreciation to this company and the people who work there. Thanks again.

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Great pricing fast shipping, flawless transaction!

All went smooth except coupon code, it said it applied 15% off but nothing happened

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Quick and easy / Affordable

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