Sailboat Self Tailing Winches

Self tailing winches are the best invention since sliced bread for sailors. Well perhaps that is not a great analogy. A potted history of deck winches is required though. Winches started off as an idea by two San Franciso sailors who owned and sailed two racing yachts called Baruna and Orient and from that we got that well known brand Barient Winch Company. The design is very similar to that formulated some 50 years ago. While manufacturers such as Lewmar, and Andersen and Harken to name but a few have evolved and improved the original design concept it is still basically the same. New generation winches are precision engineered, easy to strip down and maintain and have evolved the drum gripping surfaces to improve efficiency. Over the years the quality and reliability of gearing has improved with a variety of ratio’s available to be application specific.

Self Tailing Winches Basics

As we described earlier, a deck winch allows the exertion of force on sheets and ropes by combining leverage, the use of a longer winch drum handle on the comparatively smaller diameter drum. The winch incorporates ratchet and pawls to prevent the winch drum from rotating the incorrect and opposite way. Most winches these days are 2 speed and for some racing applications have 3 or 4 allowing for a greater degree of control over large and more powerful sails. For most average cruising yachts, the 2 speed self tailing winch is the standard. Another great thing about modern self tailing deck winches I their reliability, and this is enhanced where you join the comparatively smaller group of sailors who do the required maintenance every season. Do the maintenance and increase sail handling efficiency. 

Self Tailing Winch Basics

The self tailing winch is a basic deck winches that incorporates a stripper arm and rope jammer on the top of the winch drum.  Why we need a self tailing inch is obvious as it does way with the requirement to either struggle yourself winding and tailing alone or having someone else tail the winch as you wind. The sheet rope or line is led over the winch stripper arm and then retained within the gripper spring loaded jaws.  As an operational note when using a self tailing inch ensure that the tailed end feeds smoothly into the cockpit floor or on the deck area. Ensure you don’t stand in any loops formed on the tailed rope in case your rope lets go and hauls you out with it. 

Self Tailing Winches and Ropes

When selecting your new self tailing winch you need to also consider the proposed line size and the type of line or rope to be used on it. I learnt that lesson the hard way when I decided to replace my mast halyards for the main with a relatively thin high tech and exotic line. It caused some grief as it was rather stiff, didn’t wrap well on the drum and required more wraps and didn’t grip well in the winch jaws. Carefully consider that self tailing winch jaws effectively press the line into a triangular shape in order to apply grip. Use a line too thin it slips, use a line too big in diameter and the jaws can be damaged.  So when choosing and installing a winch make sure that you match the line or sheet size diameter with the maximum for the chosen winch.

Once you have done all the math and calculated the require tensile strength of your sheets and line, added an appropriate margin for safety say 30-50% then you can select some rope. The tradeoff and compromise will continue as you look at not just optimum line size and diameters and then matching that to your self tailing deck winch sizes, also as some consider, what material technology being used and like many the hand comfort factor. What is easy on the bare hands, as while I tend to put on sailing gloves when it’s getting a bit challenging out there, when cruising I don’t like to rip my palms up either.

What About Power Ratio

The sheet loads that are applied on a modern cruising or racing yacht can vary between 500 up to a massive 5000-pound range. The average person can produce about 50 (25 kgs) pounds of tension when pulling on a sheet.  So we are way short on the force required. The deck winch is the force multiplier used. As we have described earlier that deck winches use leverage, this being the difference between a winch drum radius and the winch handle radius. Gear reduction is then factored in, which is the number of turns required by the winch handle for each corresponding turn of the winch drum to increase the winch power.  Winch Power Ratio is the combination of these two effects. The theoretical mechanical advantage however is subject to the effects of mechanical friction which results in reduced efficiency. 

Reducing Friction in Deck Winches

If you are going to choose a new deck winch. Friction occurs at every point of a sail handling and control system. Every block and every block bearing, every angle change imposes friction losses. High quality blocks use ball bearing low friction rollers, if use old fashioned bearings then you can replace and reduce friction losses by up to 40%. Doing an appraisal of line and sheet routing can improve things, and even require a smaller winch. Another way to reduce loadings is a review of sail plans. Depending on what type of sailing you do, overlapping and non-overlapping jobs require different loadings. Mainsail reefing systems can cause some grief, and many use a single line system that runs a reefing line through multiple blocks, this creates friction and can require a lot of winching. I have seen some that propose that a 2-line system with one luff line and one leech line resolves this and while more lines is more effective, but it reduces the winch size. It is always a trade-off. So look at whether using a small number of larger and high quality turning blocks installed at optimum locations can reduce friction. More about boats and even more about self tailing winches