May 16th

Experiments with Self-Steering

Posted by // May 16, 2013 // COMMENT (0 Comments)

Boats and Gear,

I just looked through my notes and was astounded to find that we are only ten days into this trip! It seems like so much longer. In that ten days we’ve already covered about 450 (nautical) miles, developing a rhythm of passages and rests which seems to suit us well. Our first leg, the shakedown so to speak, took us about two hundred miles from New Orleans to Choctawhatchee Bay, near Destin FL and was about as close as you come to a perfect sail. We had two days of reaching so comfortably at six knots  that we were preparing full meals at least twice a day. After a weekend with friends our next leg of 250 miles to Tarpon Springs was more of a shakedown. Again we were doing mostly six knots but this was in a blustery front, skipping along in unpredictable twenty and thirty knot winds and ponderous swells. Nothing too serious, but after a couple of slightly hairy late-night sail changes I have plenty of notes on ways to rework the foresails! We like to take a good wind and run with it but even with four of us aboard we have all been getting a bit tired of handling what is often a rather heavy helm. To this end I’ve begun experimenting with sheet to tiller steering.

Ok, ok, I know the modern world all steer with a wheel, but at least on a small boat such as mine I’m still a die-hard tiller advocate. A tiller is simpler, far easier to maintain, more intuitive, more responsive, and easier to jury-rig in the event of a steering failure. Sure, a wheel is less fatiguing but that seems like a lot to trade off just for an easier time at the helm, especially when a tiller allows you to rig up self-steering without an autopilot or windvane. It’s this that I started messing with on our last passage with help from a book given to me by an old sailing friend. The book is Self-Steering for Sailing Craft by John S. Letcher, Jr. and it’s a real gem.

If you have a tiller and you come across this out-of-print book, don’t pass it up!

The windvane section, which I haven’t gotten into yet, makes up the bulk of the book but there is also a sizeable chapter on sheet-to-tiller steering. The concept is fairly simple: to the tiller (for you must have a tiller) are lashed two lines which are led to opposite sides of the cockpit. The first is (or incorporates) an elastic and is led to leeward while the second is led through a small block to windward and then tied to either the jib or mainsheet. You then adjust the tension on each until the boat steers itself.

The basic concept. This shows the jib sheet led directly to the tiller while most iterations involve a separate line hitched to the jib or main sheets.

This is how it looked in the only truly successful iteration I have tried so far:

The block on the right is looped around the windward winch and through it is a led a line which is tied to one piece of the mainsheet with a rolling hitch. When a gust hits the mainsheet tightens up, pulling at this line and keeping the boat from rounding up. The other line is a length of shock cord hitched to the tiller and tied through the leeward caprail. If the wind starts to fall off or a wave pushes the boat off course this shock cord steers to windward until the sails once again fill enough for the mainsheet to begin pulling in the opposite direction.

That is the theory, at least for most points of sail from close hauled to a broad reach. In practice I have a lot of kinks to work out. My experiments on most points of sail were failures but I did have great success when we were close-hauled. The rig pictured above actually steered the boat for hours with a reefed main in gusty winds upwards of twenty knots.

The boat steers itself while I take some photographs

On other points of sail I seem to be mainly having issues with tension, either not enough or too little. One of the issues I have been having is that this shock cord does not have quite the right stretch so I’ve spent the last day trying to track down some of the surgical tubing which Letcher recommends. We’ll see how it goes. If nothing else, fooling with this stuff is a great way to break up the monotony of a shift at the helm!

This article was syndicated from Safe At Harbour But Meant For The Sea: DIY Sailing with Paul Calder

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