Sail Trim jargon - opening and closing

[OldFrog75]

Please correct me if I'm wrong but after reading numerous articles I have inferred that "opening" the edge of a sail comes from tightening while "closing" the edge of a sail comes from loosening ie:

Tighten Outhaul = opens the foot
Tighten Cunningham = opens the luff
Tighten Vang and/or Mainsheet = opens the leech

But some articles I've read state that easing tension on the clew opens the leech. I assume that would allow the boom to rise and increase the curve of the leech thereby closing it. Am I totally upside down on my understanding of the terminology?

What is the correct jargon?

[Cotemar]

Maybe this will help

[SkiprJohn]

I don't know what you're reading so can't really comment. I've been sailing many years and teaching sailing a lot of those years. I've not used the term opening and closing and haven't met other instructors that have used the term. My initial feeling is that when you tighten the edge of a sail you are not allowing wind to pass as freely around it so you are closing?
When sheeting a sail in or out you are closing and opening the angle of the wind to the sail and that's pretty obvious but I haven't heard the term applied to adjusting halyard, outhaul, leech line or vang.
kind regards,

[daddle]

Open and closed are descriptions of a leech condition. Mostly used on a beat. Closed means the leech is near the athwartship inward limit of useful trim, or perhaps over trimmed. Open would be trimmed a little more free, more outward, perhaps not trimmed enough. May relate to the width of the 'slot' between a genoa and main. 'Opening' the head of a sail would be trimming for some more twist, for example. 'Closing' the leeches might be done to obtain pointing ability at the expense of upwind speed.

I've not heard the terms used for a luff or foot condition. The terms are not about control line tension although generally higher tensions on running rigging may close a leech. Flattening a sail can 'open' the leech. As well as changes in mast bend, or moving a lead block.

Sailing terminology is a sloppy thing. Created by sailors over hundreds of years from widely varying languages aboard all types of vessels.

[SkiprJohn]

Originally Posted by daddle

Open and closed are descriptions of a leech condition. Mostly used on a beat. Closed means the leech is near the athwartship inward limit of useful trim, or perhaps over trimmed. Open would be trimmed a little more free, more outward, perhaps not trimmed enough. May relate to the width of the 'slot' between a genoa and main. 'Opening' the head of a sail would be trimming for some more twist, for example. 'Closing' the leeches might be done to obtain pointing ability at the expense of upwind speed.

I've not heard the terms used for a luff or foot condition. The terms are not about control line tension although generally higher tensions on running rigging may close a leech. Flattening a sail can 'open' the leech. As well as changes in mast bend, or moving a lead block.

Sailing terminology is a sloppy thing. Created by sailors over hundreds of years from widely varying languages aboard all types of vessels.

Thanks for that. Just never run across it other than opening and closing the slot between jib and main.

kind regards,

[OldFrog75]

Originally Posted by SkiprJohn

I don't know what you're reading so can't really comment. I've been sailing many years and teaching sailing a lot of those years. I've not used the term opening and closing and haven't met other instructors that have used the term. My initial feeling is that when you tighten the edge of a sail you are not allowing wind to pass as freely around it so you are closing?
When sheeting a sail in or out you are closing and opening the angle of the wind to the sail and that's pretty obvious but I haven't heard the term applied to adjusting halyard, outhaul, leech line or vang.
kind regards,

As I thought I understood the concept, if you loosen all the edges you have a very baggy sail whereby the edges (head to tack, head to clew, clew to tack) are all shorter (closed); if you tightened all the edges you have a very flat sail whereby the edges are longer (open), as measured point to point.

I thought I understood the concept but I could understand it just as well if "open" and "closed" were reversed. Doesn't really matter as long as it is universally accepted and when I hear or read the terms in the future I know what is meant.

I got confused when I read a couple of different authors who stated loosening the tension on the clew "opens" the leech on the main. At that point I realized I don't understand this terminology like I thought I did.

[FSMike]

I've been sailing for a number of years and I don't have a clew what any of y'all are talking about.
Sorry.

[bobconnie]

Gee I thught I had heard some sailing terms in my almost 75 yrs, but Im with FSMike on this one I sure never heard of those terms being used anywhere !! But then I don't sit at the Bar and talk to racers and such !! LOL

[SkiprJohn]

Sail Power by Wallace Ross really is a big thick book but it covers in a chapter or two more than whatever you need to know. You might find it in your public library. It's good reading for the curious.
kind regards,

[barnakiel]

I use 'open'/'close' when I make the leech slacker/tighter.

b.

[SkiprJohn]

Originally Posted by barnakiel

I use 'open'/'close' when I make the leech slacker/tighter.

b.

Is that the adjustment you make with a leech line?

[barnakiel]

Originally Posted by SkiprJohn

Is that the adjustment you make with a leech line?

;-)

I only ever use the leech line to stop flutter.

In my case it is by lifting (or allowing to lift) the boom a notch. Boom up, less tension in the leech portion of the sail.

b.

[SkiprJohn]

Thank you Barnakiel. That's what I call adjusting for draft. Like was said many sailors have different ways of explaining things. Guess I've learned a new one.
kind regards,

[barnakiel]

Originally Posted by SkiprJohn

Thank you Barnakiel. That's what I call adjusting for draft. Like was said many sailors have different ways of explaining things. Guess I've learned a new one.
kind regards,

Yes. I think these are related and can be used together, or separately.

I believe when I make the leech tighter, all other things equal, I will move the max draft point fore. This changes how the sail works.

But I am not sure this is a 10/10 rule because I can't say, by the eye, if the amount of draft changes, or perhaps only the max draft point moves.

But I am certain that by closing the sail a bit and adjusting the outhaul and the halyard I can make the whole sail flatter (then I think there is less draft overall). If I do not close the sail, the max draft would be moved aft, towards the leech, but would it be less? Hard to say without some scientific tools.

Old tricks from my racing days. Pretty irrelevant on a typical cruising hull. Still, the sail becomes more stable and the force on the helm is less on the windy day, more on a light day, hence I will trim our sails the way I used to when it counted.

I admit my way of using open/close may well be flawed - I am not English and my sailing terms I simply copy from what I believe I have heard along the way (in this case, I believe this part of my sailing vocab comes from NZ).

b.

[OldFrog75]

Originally Posted by barnakiel

I use 'open'/'close' when I make the leech slacker/tighter.

b.

Thanks for your participation B. So if I read you right you "open" the sail by making it baggy and "close" the sail by making if flat. Is that correct?

I was questioning: "open" the foot by tightening the outhaul; "open" the leech by tightening down the boom; "open" the luff by tightening the halyard and cunningham. By your definition, all of these actions would flatten (close) the sail?