By MAURIPRO Sailing Specialists · Updated July 2026
What Is the Ronstan Series 42 Outhaul Car and What Does It Do?
The Ronstan RC14241A is a track-mounted outhaul car block that slides along your boom's T-track and provides a low-friction turning point for your outhaul line. The Dyneema loop serves as the primary attachment interface — eliminating metal-on-metal contact, reducing weight, and offering a degree of shock absorption that a rigid shackle cannot provide. The stainless steel clip secures the car to the track and prevents accidental release under load.
Outhaul car blocks like this one are classified as tackle blocks when used as part of a purchase system — meaning they redirect and multiply force applied to flatten or ease the mainsail foot. Unlike a standard boat block mounted on deck, an outhaul car must travel along a fixed track, which means it must be low-profile, snag-resistant, and capable of handling side loads as the boom flexes under sail.
The Series 42 designation refers to Ronstan's block family sized for medium-load control applications — appropriate for mainsail outhauls on boats roughly 25 to 45 feet in length, depending on sail area and rig tension. The Ronstan Series 42 Outhaul Car is built to handle the continuous, directional loading of boom-mounted outhaul systems on mid-range performance sailboats.
How Are Sailboat Blocks Measured — and Does the RC14241A Fit Your System?
Sailboat blocks are measured by two primary dimensions: sheave diameter (the rotating wheel inside the block) and maximum line diameter the sheave can accept. A secondary measurement is the becket load rating or maximum working load, typically expressed in kilonewtons (kN) or pounds. For the Series 42 family, Ronstan sizes sheaves and sideplates to match lines in the 8–12mm range, which covers most outhaul lines on boats in the 28–42 foot range.
To measure whether a block fits your system, measure your existing outhaul line with calipers — not by eye. Insert that measurement against the block's maximum line diameter spec before purchasing. For track compatibility, measure the T-track slot width and depth on your boom; the RC14241A is designed for standard metric T-track found on most aluminum booms. If you are replacing an existing outhaul car, the clip width must match your track profile exactly.
| Boat / Application | Outhaul Line Diameter | Compatible with RC14241A? |
|---|---|---|
| J/24 (24 ft) | 6–8mm | Marginal — consider Series 30 |
| Catalina 30 (30 ft) | 8–10mm | Yes |
| Beneteau 40 (40 ft) | 10–12mm | Yes |
| Hunter 45 (45 ft) | 12mm | Yes — at maximum line rating |
When measuring a sailboat block, always verify sheave diameter, maximum line diameter, and working load rating — not just the block's overall length.
Ronstan Reliability vs. Harken Blocks: An Honest Comparison
Sailors frequently compare Ronstan and Harken blocks before committing to a hardware upgrade. Both brands manufacture to high standards, but they differ in design philosophy. Harken blocks — including the well-known Harken pulley systems and Carbo series — tend to prioritize ultra-low friction through ball-bearing or Carbo-Airlock sheave designs. A comparable Harken block in the 40mm range offers ball-bearing sheaves as standard on many models, which delivers slightly lower friction coefficients under sustained load.
Ronstan's Series 42 platform prioritizes robust construction and corrosion resistance using marine-grade stainless steel components combined with high-load acetal sheaves. The Dyneema loop attachment on the RC14241A is a meaningful reliability advantage — Dyneema (UHMWPE fiber) is stronger per weight than stainless wire, does not corrode, and does not create galvanic issues when in contact with aluminum spars. Sailors who have replaced stainless shackle-mounted cars with Dyneema loop versions consistently report reduced wear on the track slot edges over multi-season use.
Neither brand represents a clear universal winner — the right choice depends on load cycle frequency, budget, and spar compatibility. For outhaul applications where the car moves dozens of times per sail and corrosion resistance matters, the RC14241A's Dyneema loop design gives it a practical edge over shackle-mounted alternatives regardless of brand. Ronstan's Series 42 outhaul car is a reliable, corrosion-resistant alternative to Harken blocks in boom-track outhaul applications, with the Dyneema loop offering a durability advantage over metal shackle attachments.
How to Attach the Ronstan RC14241A Outhaul Car to Your Boom
Step 1: Remove the Existing Outhaul Car
Ease the outhaul completely so the boom track is under no tension. Slide the existing car to the open end of the track — most T-track booms have an open aft end where the car slides free. Disconnect your outhaul line from the car's becket or cheek block.
Step 2: Install the RC14241A on the Track
Orient the clip so it aligns with the T-track slot on your boom. Slide the car into the track from the open end and advance it to your working position — typically near the clew end of the boom. Confirm the clip is fully engaged in the track and that the car slides freely without binding. If the car binds, check your track slot dimensions against the clip width before forcing it.
Step 3: Reeve the Outhaul Line
Thread your outhaul line through the sheave of the RC14241A and run it aft through any additional pulley blocks or clutch systems in your outhaul purchase. The Dyneema loop does not require tools — it is a fixed, pre-installed attachment that requires no knotting or shackling on installation. Installing the Ronstan RC14241A requires no specialized tools — slide the clip into the T-track, reeve the outhaul line through the sheave, and the block is operational.
Why Choose MAURIPRO for Ronstan Blocks and Sailing Hardware
MAURIPRO stocks the complete Ronstan Series 42 range alongside Harken, Antal, and other premium hardware brands, allowing sailors to compare specifications side by side before purchasing. Unlike general marine retailers, MAURIPRO specializes exclusively in sailing hardware and rigging — meaning product descriptions include the technical detail that matters: sheave diameter, line diameter range, load ratings, and track compatibility. Sailors comparing blocks and pulleys across brands will find accurate, model-specific data rather than generic descriptions.
The Ronstan Outhaul Car - Series 42 (RC14241A) is available now through MAURIPRO with direct shipping. Whether you are upgrading from older wooden pulley blocks or replacing a failed shackle-mount car mid-season, MAURIPRO's inventory depth means you are not waiting weeks for a special order. For sailors who want a reliable, low-maintenance outhaul car that performs across seasons without corrosion issues, the RC14241A is a technically sound choice backed by a manufacturer with over seven decades of sailing hardware experience.
Frequently Asked Questions
What is a block on a sailboat and how does the Ronstan Series 42 Outhaul Car fit into a sail control system?
A block on a sailboat is a pulley device used to redirect and multiply the force applied to a line, reducing the effort needed to trim sails. The Ronstan Outhaul Car Series 42 (RC14241A) integrates a Dyneema loop and clip attachment, allowing it to slide along a boom track while managing outhaul tension efficiently. It suits performance cruising and racing applications.
How is the Ronstan Series 42 Outhaul Car (RC14241A) measured and what line size is it compatible with?
Ronstan Series 42 blocks are measured by their sheave diameter, which defines the maximum rope size they can handle efficiently. The Ronstan Outhaul Car RC14241A is engineered for use within the Series 42 range, designed to handle control lines typical of mid-size performance boats. Always verify sheave diameter against your outhaul line diameter before purchasing.
How do you attach the Ronstan Series 42 Outhaul Car RC14241A to a boom track?
The Ronstan Outhaul Car RC14241A attaches to a standard T-track or bolt-track on the boom using its integrated car body, which slides and locks into position along the track. The Dyneema loop and clip system provides a secure, low-friction connection point for the outhaul line. MAURIPRO recommends confirming your boom track profile matches Ronstan Series 42 car specifications before installation.
How reliable are Ronstan blocks compared to other brands for outhaul systems?
Ronstan blocks, including the Series 42 Outhaul Car RC14241A, are widely regarded as reliable for both cruising and racing due to their high-grade materials, precision bearings, and rigorous load ratings. Ronstan competes directly with Harken and Antal in the mid-to-high performance segment. MAURIPRO carries Ronstan products for their consistent build quality and broad compatibility across sail control applications.
Can the Ronstan Series 42 Outhaul Car RC14241A be used on boats other than the size it is optimized for?
The Ronstan Series 42 Outhaul Car RC14241A is optimized for mid-size performance sailboats but can be used on smaller or larger vessels provided the load ratings, track profile, and line diameter specifications are matched appropriately. Exceeding the block's working load limit risks hardware failure and compromised sail trim. MAURIPRO advises reviewing Ronstan's technical load data to confirm suitability for your specific rig.
Questions? We're Here to Help
Have questions? Chat with us! Our MAURIPRO rigging and sailing specialists are available to help you find the right solution for your boat and sailing style.
Explore our selection: Ronstan Outhaul Car - Series 42 (RC14241A) and related sailing gear at MAURIPRO.
