Reducing Friction in Running Rigging Systems

Key Takeaways: If your running rigging feels heavier than it should, the culprit is usually friction. The quickest wins come from correctly sized blocks, clean sheaves, low stretch lines, and well aligned clutches. Even tiny misalignments can make a line feel twice as heavy. Upgrading the highest load runs to ball bearing blocks often transforms sail handling on a cruising boat.

Why Friction Matters More Than You Think
Understanding Where Friction Builds Up
Block Sizing and Sheave Condition
Line Selection and Stretch Behaviour
Clutch Alignment and Lead Angles
When to Upgrade to Ball Bearing Hardware
Hidden Sources of Drag on Cruising Boats
Maintenance Habits That Keep Friction Low
Summing Up

Why Friction Matters More Than You Think

Most cruisers notice friction only when something feels stiff or reluctant, but the real impact is broader. High friction slows reefing, makes trimming harder, and encourages poor sail shape because the crew simply stops adjusting things. On a breezy day, friction can turn a simple reef into a wrestling match. Reducing it restores control and confidence.

Understanding Where Friction Builds Up

Friction rarely comes from one dramatic fault. It accumulates in small increments across the system. A slightly worn sheave, a tired line, a clutch that is a few degrees off, or a block that is marginal for the load all contribute. The running rigging is a chain, and every link matters.

On the Water...

When we built 'Alacazam', we decided to terminate all halyards and reefing lines at the mast, rather than leading them back to the cockpit. This avoided having turning blocks and deck organisers which undoubtably reduced friction in the system, but was less than ideal in boistrous conditions.

Block Sizing and Sheave Condition

Correct block sizing is fundamental. Undersized blocks force the line to bend too tightly, increasing resistance and wear. Oversized blocks are not harmful, but they add weight and cost without real benefit.

Sheave condition is equally important. Dirt, salt crystals, and minor scoring on the bearing surface all increase drag. A sheave that spins freely under finger pressure is ideal. If it feels gritty or sluggish, it is already costing you effort.

Recommended Block Checks

Use the following table as a quick reference for assessing block condition and suitability.

Area	What to Check	Action
Sheave rotation	Smoothness, free spinning	Clean or replace
Block size	Diameter relative to line size	Upsize if line bend is tight
Side plate wear	Grooves or scoring	Replace

Line Selection and Stretch Behaviour

Low stretch lines reduce friction because they transmit load more cleanly. A stretchy line compresses and flattens as it passes through a block or clutch, increasing resistance. Modern polyester lines are fine for many cruising applications, but high load runs benefit from Dyneema or similar fibres.

Diameter matters too. A line that is too fat for the sheave or clutch will drag. A line that is too thin may slip. Matching line diameter to hardware specifications is one of the easiest friction wins.

Thinking of renewing your sheets, halyards or control lines? Here's our suggestions for matching cordage with applications...

Clutch Alignment and Lead Angles

Clutches are often installed where they fit, not where they should be. Even a small misalignment between the clutch and the winch can double the load required to trim a sail. The line should run straight from the clutch to the winch drum without sideways deflection.

If the clutch is slightly off, the line rubs on the side plates, creating heat and wear. Correcting alignment is usually a matter of repositioning the clutch or adjusting the organiser beneath it.

When to Upgrade to Ball Bearing Hardware

Ball bearing blocks shine on high load runs. The vang, mainsheet, and genoa sheets are the usual suspects. These lines carry significant load and move frequently, so any reduction in friction is immediately noticeable.

Plain bearing blocks are fine for low load or static runs, but cruisers often underestimate how much easier life becomes when the key systems run on ball bearings. The difference is especially clear when reefing or easing the mainsheet in gusty conditions.

Hidden Sources of Drag on Cruising Boats

A few friction sources often go unnoticed:

Salt build-up inside organisers: Organisers are rarely inspected, yet they carry multiple high load lines.

Ageing rope covers: A glazed or hardened cover increases drag dramatically.

Bent fairleads: A fairlead that has taken a knock can distort the line path.

Winch drum contamination: Dirt and old grease reduce grip and increase effort.

These small issues accumulate until sail handling feels heavy and uncooperative.

Maintenance Habits That Keep Friction Low

A simple maintenance routine keeps friction under control:

Rinse blocks and sheaves with fresh water after passages.

Inspect clutches annually and replace worn cams.

Clean winch drums and re-grease internal gears.

Replace lines that show glazing or hard spots.

Check organiser sheaves for free rotation.

None of this is complicated, but it pays off every time you trim a sail.

Summing Up

Optimising friction in your running rigging is not about chasing perfection. It is about removing the small obstacles that make sail handling harder than it needs to be. A few thoughtful upgrades and a bit of regular care can turn a reluctant system into one that responds smoothly and predictably. When the rigging runs freely, the boat feels lighter on her feet and far more enjoyable to sail.

This article was written by Dick McClary, RYA Yachtmaster and author of the RYA publications 'Offshore Sailing' and 'Fishing Afloat', member of The Yachting Journalists Association (YJA), erstwhile member of the Ocean Cruising Club (OCC) and owner/administrator of 'Liveaboard Sailboats for Sale'.