Following Sea: Telltales are simple but effective tools for staying on course

Quite a few people recently have asked me about telltales and how to read them. I have written about them before, but there is always more to be said about such an important and simple aid to boat trim.

A telltale is a piece of string, plastic, yarn or even cassette tape put on a sail to help determine wind direction and sail trim.

What a great and simple idea!

Attach a piece of yarn, plastic or other material to the sail that can stream with the wind, and you have a vital instrument. It does not need battery power, lasts a long time and is very inexpensive.

On the other hand, it does not come with a manual, so you need to know how to read it.

If you are racing, cruising or just out for a day sail, the proper way to sail the boat is usually in the groove. This is when the boat is trimmed correctly to the wind, no matter what direction it is coming from, and is achieving optimum speed.

A good helmsman may be able to keep the boat in the groove by feel only for short periods, but I do not know anyone who does not use and need telltales while steering a sailboat for any amount of time.

We also must consider that wind and sea conditions are always changing. Whether the changes are drastic or subtle, the telltales will tell you which way the wind is shifting, and you can change the course or trim of the boat accordingly.

Imagine a boat with no telltales, masthead fly or other wind-indicating devices. A person who knows the wind will be able to eventually trim the boat close to where it should be, but it probably will not be optimum.

Since the conditions are always changing, the course and trim changes will be slow, often wrong, and not very pretty or effective. More often, huge wind shifts are misidentified and can put the boat in a dangerous position.

We can compare sailing a boat without telltales to trying to navigate a forest at night without a flashlight. We'd have to feel our way around to get somewhere. We probably would get there eventually, but it would be a lot easier and safer with a flashlight.

Now, where should you put telltales on your sailboat?

Remember that a sail is like the wing of a plane — it creates lift from variations in air pressure when air flows over it.

On a sloop, put the first set of telltales on both sides of the headsail near the luft, or front, of the sail. Placing them in three pairs up the luft usually will give a good idea of what the jib is doing and how the air is flowing along it. These telltales will be critical in telling the helmsman which way he needs to steer to grab the wind.

Now put some single telltales down the leech of the main.

Usually four or five will do.

These will tell you how the wind is flowing over and off the mainsail.

Now that you have telltales, the boat will be much easier to steer and to hold proper course.

Pretend you are on a beat during a race and are trimmed in hard to the wind. The ideal position of the headsail telltales is streaming straight back with the inside tales lifting up for a second once in a while. The main telltales should flow straight back off the leech of the main.

Now the boat is slowing down. The inside telltales are fluttering straight up or flopping all over the place. The outside ones still look OK. What does this tell you?

Either the helmsman came up too close to the wind and "pinched," or the boat is being "headed," meaning the wind shifts more toward the bow of the boat. In either case, the boat must be eased off the wind until the telltales are flowing properly again.

What if the outside telltales flow straight up or begin to flop around? You guessed it — the exact opposite needs to happen.

Although other factors have an effect on boat trim and course, the basic language of the telltales stays pretty much the same. I think the telltales are harder to use and less effective when you sail downwind, but many spinnakers have them as well. With practice, you will get it.

With all of the modern navigational aids available today, I think you will find that the telltales are still your primary source of information when it comes to wind direction.

Combine them with your masthead fly on the top of the mast, and you can turn off the fancy electronics and go.

I do not know, nor do I think history knows, the first ancient mariner to stick a piece of string or hemp on his sail, or when he did it. Whoever he was, he had a great idea.