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daydreamer92 03-18-2010 09:32 PM

Genoa question(s)
My understanding of a working job was it was your basic 100% jib. I know there can be smaller, down to a storm jib.

I've recently come across the term "working genoa", though. Is that a standard size (%) of genoa? Or is that another way of saying "a basic 100% jib"?

Also, how does one decide which "percent" genoa to carry? They seem to come in all percentiles, from 105% to like 175%. I was reading a Tartan 27 handbook I just got (chock full o' T27 stuff, whee) and it mentions a 176% genoa.

Our boat just came with one head sail, a 140%, a hanked on deal. I suppose we outta get a smaller head sail at some point, but reading this handbook got me curious about definitions. Google didn't spit up much helpful other than telling me genoa and jib is sometimes used interchangeably.

sailingdog 03-18-2010 10:20 PM

A lot of this depends on where you sail. Buzzards Bay often drives people to drop down to a smaller headsail, since the afternoon winds can be pretty interesting... Some of this depends on the boat and the way it is setup. For instance, on a boat with a roller-furling headsail, you might go a bit larger than you would if you had hanked on sails, since you can reef it by rolling it up a bit.

A 176% genny is ridiculous IMHO. Largest commonly used Genny is a 150% like I have on my boat. If you need more sail area for light winds, you're better off with an asym. or a screacher.

BTW, will you be down in Mattapoisett tomorrow?? I'm going down to do some work on my boat in the AM. Be heading back mid-afternoon.

BarryL 03-18-2010 10:58 PM


The mast, forestay and deck make a triangle. If the headsail fits within that triangle the sail size is 100%, or more commonly known as a jib. If the sail is larger than that triangle, it is a genoa. If the sail is 50% larger than the triangle, it is a 150 genoa (150% larger).

Racers don't use numbers like that. They will have a #1, typically a large genoa, like a 150, a #2, like a 135, and a #3, or a jib. Some will have light and heavy #1, and #2, etc, so that they have a sail for all wind conditions.

Typically, the smaller the boat, the larger number genoa they carry. A small boat like a 22' may use a 150 or even larger, but a big boat, like a 40 would not usually have a sail so large. A 150 on a small boat is still a fairly small sail, so it won't be that difficult to tack, jibe, and trim. A big boat, with a large fore triangle, will have a bigger sail, and this requires more effort to trim (even with larger winches).

IMHO, the condition of the sail is way more important than the size of the sail. I would much rather have a 150 in good condition than a 135 that is blown out. Just sail the boat for the first year and see how she does and how the sail works. A 140 may be fine for you. Unless you are in a real windy place (like San Francisco), it's probably OK. And, as mentioned, a foller furler makes things a lot easier. When I was in the market for a new headsail I bought a 140 that can be reefed down to a 110.

Good luck,

sailingdog 03-18-2010 11:15 PM

Not quite accurate Barry. The Genoa size is determined by LP measurement, not area. Of course, if you have an oddly shaped sail, say a genny with a high cut clew to allow you to see under it more easily, the measurement of LP changes slightly than if you had the same sail with a normal foot and clew.

From the wikipedia entry on genoas...


The term genoa is often used somewhat interchangeably with jib, but technically there is a clear delineation. A jib is no larger than the foretriangle, which is the triangular area formed by the mast, deck or bowsprit, and forestay. A genoa is larger, with the leech going past the mast and overlapping the mainsail. To maximize sail area the foot of the sail is generally parallel and very close to the deck when close hauled. Genoas are categorized by the percentage of overlap. This is calculated by looking at the distance along a perpendicular line from the luff of the genoa to the clew, called the LP (for "luff perpendicular"). A 150% genoa would have an LP 50% larger than the foretriangle length. Sail racing classes often specify a limit to genoa size. Different classes of genoa have overlaps; a number 1 genoa may be a 150%, and a number 2 genoa, 125%. Jibs are also defined by the same measure, with overlaps of 100% or less. Under Performance Handicap Racing Fleet rules most boats are allowed 155% genoas without a penalty.[2]

blt2ski 03-19-2010 09:14 PM

The % genoa will depend not only on the LP, but the sq footage too, depending upon if you race. Here in PHRF-NW the 150 is 150% of the 100% foretriangle. IE we use actual sail area around here from a rating stand point,

Some manufactures like Jeanneau, currently use a max of 135, and that is designed to be the largest headsail. BUT< to get to a 22-1 SA/Disp for decent performance of the boats, they use a larger main than one would if a boat is designed with a 155 max head sail like my boat. Some boats like a C&C 115, X yachts and some Hanse's, the max head sail is a 110, they are fractional setups, and as such, have HUGE mains in relation to my boat as an example. My 155 is 345#< where as my main is only 195. Where as some boats will be the opposite, a main of say 345, but a 110 jib of 195, giving you 540# on a 6500 lb boat and a 24.5-1 SA disp.

Now from the OP's std point, some boats I would surmise to call a 120-140 a working genoa, something bigger than a 110, ie std typical max for a jib but smaller than a 155 or for some boats back in the late 60's and early 70's designed for the IOR rule, would use head sails in the 160-170 range.

Today most would use an Asymetrical for when you wanted a BIG genoa in the 170 range as mentioned. I can point upwards of 55-60* with my AS.


daydreamer92 03-20-2010 12:40 AM

Thanks for all the replies. As usual, very educational!

sailingfool 03-21-2010 09:52 AM

54 Attachment(s)
I would say the term "working genoa" is mis-using the term "working jib". I have never heard the term working genoa used other than in this post.

FSMike 03-21-2010 04:49 PM

I was taught that all genoas are jibs but not all jibs are genoas.
Terminology evolves.

sailkeys92 01-04-2011 11:21 AM

Hey daydreamer,
I just bought a T27, and was wondering where you found the T27 Handbook. I haven't been able to find it anywhere online. Thanks.

daydreamer92 01-12-2011 02:03 PM

Hi there, sorry for the late reply. I'm still around, just in the throes of an out of state move, so haven't been checking this forum much :(

The T27 handbook is compiled by the Chesapeake Bay Tartan Sailing Club. Here's a link to their website. Look in the nav bar on the right for ordering info.

CBTSC -- Keeping Sailing in Your Future !!!!

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