DaySailer.org Forum

Is sailing close-hauled with only the mainsail much less efficient (or even possible) than with both main and jib -- or is our boat out of whack?

I should add, she sails beautifully on a reach with main only .

To answer your question about it being "much less efficient", the first part of the answer is it's relative to what your doing. Racing, yes not only in speed, but in the boats ability to point and stay flat when your sailing close hauled. Can you sail with just the main, yes. I do it all the time. I just find that the balance of the boat is better when i'm flying the main and the jib.

then again, I'm just a rookie and have a lot more to learn.

I'm very new as well - but I can't seem to get anywhere if I don't use the jib along with the main - I just have no ability to completely make it through a tack in light winds because the jib seems to be instrumental in steering.

Your boats ability to point is directly related to the Jib and how your using it.

Can i ask, are you sailing alone, and do you have a tiller tamer?

Sail alone and with others. Don't have a tamer but am thinking about it. I do use the jib and she does handle better with it in pointing, power and balance.

I think I see now that close-hauled with only the main is less effective because of the angle of the wind (without the jib to redirect it), whereas on a reach it is blowing more directly into the sail (main).

I agree with Sean re: light winds and steering.

I like to carry a little momentum into my turns and without the jib the boat just stalls as soon as it heads into the wind. With the jib, you can literally feel the jib carry the bow through the turn.

But the bigger difference comes in higher or gustier winds. Without the jib, the boat seems unbalanced and rides a little higher in the bow. When you start your turn, the winds have a tendency to push on the hull, you find yourself in irons very easily, and she won't respond at all to the tiller. She just stalls and eventually the wind beating on the hull starts pushing you backwards. It gets pretty frustrating, or depending how close you are to an immovable object, can be a little embarrassing, as well. I've been run aground a time or two just for that reason.

I've sailed smaller boats (14's) that do well with main only, but my DS seems to like both.

To you newer singlehand sailors out there, if you find sailing with both sails a little too complicated or intimidating, it really isn't. You have a little more "housekeeping" to do when making your turns, but the benefits far outweigh the difficulties.

If your jib sheets are run correctly, and within easy reach, it just takes a few seconds to release one sheet and then cleat the other side. I usually release the sheet just as I start my turn and snap it over after I've completed it.

It's easy and when you actually set it is really just a matter of preference.

Peter,

Thanks. You described exactly what we were experiencing. Using both sails is best.

I must say, though, that on a reach, with only the main, she really flew! I can't imagine that adding the jib would make her any faster on a reach, but if so we are in for a treat!

I agree with the additional "housekeeping". This is why i find a tiller tamer to be so helpful. In the event that you need both hands, the tamer allows that.

Jason

To jump on the bandwagon I have to agree with others on this topic. All sloops are more efficient with the jib than on the mainsail alone but the DS is more so than most. I used to sail a Mariner on main alone almost as much as with both sails and would simply lift the board until it balanced out nicely. This trick doesn't seem to work with the DS.

So what I do with the DS is get the power from the jib and use the main to find my balance point. It doen't mean flogging the sails but certainly taking the drive away. I usually tighten the outhaul and downhaul then let it out some. I will backwind the main some if its heavier winds so there's a bubble on the mains luff. This keeps it from heeling as much.

Downwind I simply don't let the main out as much so there's less area and "S" jibe or even chicken jibe if needed. Practice S jibes in light air first.

I don't like tiller tamers, if I fall overboard I want my boat to stop and wait for me instead of sailing away. Never happened just a phobia I have.

Fred

If your sailing close-hauled you will some times be very close to the edge of the no go zone and its easier to stall out in a tack from there. If you come off of the wind some and pick up a little more boat speed right before you tack it will really help get you through. At least that's what works for me a lot of the times.

The jib serves the purpose of increasing the windspeed over the main by forcing it through the slot between the two sails. The increased speed (Bernoulli Effect) creates more lift (power) in the main which is the real seat of power in our boats. This is why it is important to trim both sails to work together.

Actually, that's not how the aerodynamics work.

The jib does influence the airflow around the main, with the result that the main can be sheeted in further when a jib is present, for example. However, contrary to an oft-repeated explanation, the air in the "slot" between the two sails, is actually slower than it would be without the jib.

Arvel Gentry put the record straight on that one in a series of articles in SAIL magazine that appeared in the early 70s. I found those fascinating reading. They contain a very clear exposition of the details, including data from his own measurements.

The articles are collected at http://www.arvelgentry.com (look for the "magazine articles" link). There are also HTML pages that present more or less the same material, but they are white on black, which I find much harder to read.

BTW, a nice book which gives a concise recap of this and other scientific facts relating to sailboats is Bryan D. Anderson's small volume "The Physics of Sailing Explained".

Interesting reading. Thanks

You're welcome. Glad you find it interesting.

I remember, I was rather surpised when I first heard about Gentry's work, because the slot theory was all over the sailing literature when I first started reading, even though his work had long been published by then.

Is that what the "slot effect" was? Is it now debunked? If not, what is the slot effect?