self steering by tiller sail

[tillersail]

I occasionally lash a 3m telescopic painting pole to the tiller. The pole, which extends directly out from the stern, supports a small fore and aft sail (approx 4 sq feet) which acts like a fin. The sail can be extended, retracted or feathered by adjusting the pole. In a gust, the sail moves to leeward pulling the tiller to windward and the boat bears away. Tiller movement is counteracted by a length of shock cord leading from the leeward coaming. Sail efficiency is not compromised and there is no cats cradle of blocks and lines in the cockpit. It works well enough and I wonder if anyone else has tried this method of self-steering by tiller sail? Tony C

<hr width=100% size=1>

 

[homa]

"In a gust the boat bears away"

I can't think of anything more dangerous, This post must be a joke......?

<hr width=100% size=1>

 

[homa]

"In a gust the boat bears away"

I can't think of anything more dangerous, This post must be a joke......?

<hr width=100% size=1>

 

[homa]

"In a gust the boat bears away"

I can't think of anything more dangerous, This post must be a joke......?

<hr width=100% size=1>

 

[DeeGee]

You seem to have this the wrong way round. The windvane on self-steering (your 4ft sail) will be flagging when it is doing nothing, ie the boat is on the desired heading. Now, the wind moves more aft (due to velocity shift, or gust, or due to a simple shift). Under those conditions, we want the boat to turn toward the wind, not away, but by pushing the helm to windward, you are indeed bearing away. That is not self-steering.... agreed, when reaching, the technique is to bear away so as to use the puff, but that is not self-steering, which is about adjusting the boat's heading for shifts in the wind. That is why there are the cat's cradles, reversing the effect to push the helm to leeward.

The answer to your question is that YES, others have done this, as (with the reversing) the first simple s/s systems consisted of a windvane acting on the rudder, and then they acquired hydraulic power via a servo pendulum.

<hr width=100% size=1>Black Sugar - the sweetest of all

 

[tillersail]

If the boat is well-balanced and its sails adjusted for sailing at the desired angle to the wind, a corrrectly set tiller sail helps to keep them there. It is working the tiller continually and only flags when it is feathered horizontally and not required. Apparently, tiller sails go back quite a long way. They are just a variation of sheet to tiller rigs which work on the idea that most well-balance boats will hold a steady course when close hauled in a steady breeze. In a puff, these systems pull the helm to weather.

<hr width=100% size=1>

 

[DeeGee]

I really cannot understand how your system is working. It makes no sense. However, you know what it is doing, and if it is working, then it is working.

But I don't think it will work generally. If your sail is full enough of wind to hold the boat on a steady course, and the wind comes up, it will cause the boat to bear away. This will put more pressure on the sail, and so the helm will end up as hard to weather as the sail force can push it. Most boats would then go on round to a gybe. Presumably, the sailforce in your case is not enough to counter the weather helm which develops as the boat bears away, now becoming unbalanced.

I can assure you that EVERY commercially available self-steering system uses things in reverse to the way you suggest.

<hr width=100% size=1>Black Sugar - the sweetest of all

 

[charles_reed]

With a well-balanced boat you shouldn't need your laundry line.

Just adjust the sailplan and sheets and lash the tiller and the boat will go to windward with only 2-3 degrees of variation.

The rub occurs when you try and reach or run, especially when it's gusty or the boat is surfing - then the only thing that will work is an electric autopilot - vane gears are useless under those conditions.

<hr width=100% size=1>