Not quite... A Jib is a 100% (or less) foretriangle headsail.. A genoa is typically a 120 to 155% foretriangle headsail. Both are set and used similarly, with jibs being deployed in heavier air, genoas lighter.

A symmetrical spinnaker is quite different. Colourful, yes.. Usually made of lighter nylon material but it is a 'flying' sail that sets ahead of the forestay usually on a pole.

Cruising spinnakers, drifters, Asails, etc more closely approximate large, light, colourful genoas.. They do not attach to the forestay like jibs and genoas, and don't usually need/use a pole, though short bowsprits are often used.

Hope that helps a bit.

 

Thank you. Can you please elaborate what you mean by 100% foretriangle?

 

I echo Faster completely.

Practical difference in spinnakers he describes:

Symmetrical spinny = doesn't beam reach as well as asymmetrical because it is way more curved, but will sail a deep broad reach or a dead run way better since its pole pulls it laterally out of the way of the blanketing effect of the mainsail. And when you jibe it, you send someone forward and shift only the pole, and don't have to "reverse" the side of the spinny presented to the wind.

Assymmetrical ("a-sim") spinnaker: Good reacher and broad reacher, but nearly useless on a deep broad reach or a run since it is "pinned" to boat's centerline and cant be swung out from behind the dead-air behind the mainsail. It can be useful if you "wing it out" on a dead run, but requires major concentration from helmsman since the "sweet spot" is really narrow laterally. Also to jibe it, you have to "wipe" the sail over itself, lots of exercise for your trimmers. But, you dont have to send anyone out forward of the mast to jibe it.


New sailors may want to get a couple of dozen sails under their belts before trying the spinny of either type, then pick a nice 5-10 knot maximum wind to try it out. 8 knots would be perfect. Unllike mainsails or jibs, spinnakers are attached only at the corners, so are less controllable animals.

 

Roughly speaking, if the jib comes back to the mast (but not past it), it is a 100% jib - it covers 100% of the space between the mast and the front of the boat (forestay). In heavier winds, you use a smaller sail - 90% is common. In lighter winds, a larger sail (which is called a Genoa, so named after the boats in Genoa, Italy, that used big foresails).

How much is heavier wind? It all depends on the boat (and other factors like your skill, and even your budget). Generally if a boat leans (heels) over too much, it makes for an exciting ride, but is less efficient and slower. So you need to control the heel, and reducing sail size is one way of doing this.

 

I would respectfully wish to correct or at least clarify some points made above. The term "Jib" is a generic term for all of the triangular headsails. Genoas are a just one type of Jib, and as noted generally refers to jibs which overlap the mast. In common usage, people will often refer in short-hand to their working jib as their 'jib'. Working jibs are vary in size from less than 100% foretriangle sails (such as would be the case with a self-taking jib) to what are effectively small genoas, typically less than around 110%. Working jibs are often cut fuller than #3 genoas to give them a wider wind range.

Jeff

 

Ha... now lemme confuse things more
Lapper, bigger than a "working jib" (which I had always though was less than 100%) but smaller than a genoa (usually less than a 120%).
So a 110% is a lapper.

I've heard old salts refer to working jibs as "painters" too, which struck me as odd, because I always thought that was just for a forward line...

Then there is a storm jib.

 

And THEN..... many boats' sailbags will be labeled '#1 Genoa', '#1 Light', "#2 heavy" '#3 jib'... and then '1/2 0z chute', '3/4 oz chute', '1.5 oz chute'.

With jibs/genoas the #1s are the larger headsails, usually 155%(that's to do with rating penalty limits), you may have a couple of different clothweights and shaped cambers... #2s are usually the mid range sails, typically 120-130%LP... and #3s down to the working jibs, even a #4 that is a smaller jib, not quite to the storm jib situation... all with progressively heavier cloth and refined shapes for the expected conditions..

The spinnakers are different weighted cloth, and usually different designs to deal with progressively heavier wind, and/or specialized designs for reaching vs running..

In the heyday of IOR racing plenty of boats had 12 - 20 or so sails in their inventory

Sorry you asked yet???

 

...and on to my favorite bit of headsail trivia - the "yankee" is a jib in the shape of an equilateral triangle (high clew). As it is symmetrical it doesn't matter which end is the head, and which the tack; in fact, it is so simple (the British sailors say) that even a yankee can raise it.

Thus the term.

 

Oh my aching head! way too many choices, definitions........OUCH.......oh my aching head.......

With that I better leave this place of confusion before someone intro's other sails like reachers, screachers, bloopers, staysails, mizzens......oh dear!...........its WOMBY's fault...........

 

Too make matters worse is inside the universe of ASMs there are all kinds of variations to take you from reaching to DDW and now there's the Parasailor which works from DDW to a reach and is typically flown with the main sail down.
Plus there are all the variations of jibs on the oldtime big boys. How glorious to see a fisherman, jib, and staysail in front of the foremast of a big schooner.

 

Yep, jib is a generic name. The other names have morphed over the years. I like to think of the clew as the overlap point. The clew of a working jib will never overlap the mast. For example, on the J-24 that I sailed on, sail bags were stenciled with percentages. 80%; 90%; 100%; 150%. 100% meant that it met the mast, but did not overlap the mast. You chose a smaller worker if the winds were up. Racing boats give jibs numbers, but I thought it was a neat idea to show the percentages on the sail bags.

The storm jib (sometimes called a "spitfire") also has a clew that will not overlap the mast. It's just shorter on the luff and has a higher clew for better under-the-foot visibility and to prevent boarding seas from pounding the sail. Sails that overlap the mast might be called lapper (or mule), Genoa or some such. When I was taking sailmaking courses back in the 70's from Jim Grant at Sailrite, we had to design (by hand back then), working jib, storm jib, lapper, Genoa, and staysail in one part of the course. We had to build one of those. I chose to build a lapper that I had designed for my Cape Dory 27. If I recall, it was about 123% and I made the luff just a bit shorter than full hoist and the clew a bit higher (I singlehanded, so visibility was super important). Quite powerful and easy to handle.

 

Ok, I added to the confusion of this thread originally... then others piled on... and it's an old thread anyway (2 years anyway)... so I'm going to have fun with THIS graphic too... because it shows the sizes/cuts of various spinnakers too!
here are the Assymetrical Reaching, and Running codes.

Plus there are similar code sizes for symmetricals.

 

My understanding is:
1.Gib is the most basic kind of foresail
2.Genoa is a large jib
3.Spinnaker is a colorful genoa.

Is this correct?

Try Wiki?

 

Ancient thread.

 

Argh.. old post.. my apologies. Didn't read date