...about Sailing Terms, But Were Afraid to Ask. Almost nothing on a boat has the same name as it has on shore. Bathrooms are heads; kitchens are galleys; floors are decks or soles. We have leeches and luffs, and feet, and tacks and clews and heads (the other kind) and pintles and gudgeons and...well the list goes on almost forever. So it shouldn't be surprising that we all don't know all the terms. Yet pride in our sailing knowledge and our fragile egos sometimes make us embarrassed to ask questions and reveal (gasp) a hole in our sailing education. Well here's your chance. What sailing term(s) have you always wondered about but couldn't bring yourself to ask? I have two: 1. What exactly is a "full roach main"? Is this when you take your main out of the sil locker at the begiining of the season to find that cockroaches invaded your boat? Somehow I don't think so. 2. What exactly is a "fractional rig"? Is this what you have left after a dismasting that you limp home with? Somehow I doubt it. But I don't know. I've got about a gazillion sailing books but can't find these terms defined. So somebody please help. And what about you. Is there some term out there you've been wondering about? If you're too embarrased you could always send it in under a fake name. But come clean. It's good for the psyche!
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Tom M.
Terms
Gary, as I understand it a fractional rig is where the jib forestay doesn't go all the way to the top of the mast (masthead rig) this is also referred to as a 7/8 rig (?) A full roach main is one that the luff is curved perhaps out past the topping lift as opposed to being in a straight line from the end of the boom to the masthead. I could be mistaken though I beleive that is correct. A good book for some of this stuff is Royces Sailing Illustrated.
Gary, as I understand it a fractional rig is where the jib forestay doesn't go all the way to the top of the mast (masthead rig) this is also referred to as a 7/8 rig (?) A full roach main is one that the luff is curved perhaps out past the topping lift as opposed to being in a straight line from the end of the boom to the masthead. I could be mistaken though I beleive that is correct. A good book for some of this stuff is Royces Sailing Illustrated.
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Rodney Kidd
Tom is Correct
Gary, Tom is correct. A fractional rig is one in which the forestay does not go to the masthead but is rigged some distance below. Later Hunters are fractionaly rigged, most Catalina's are not. The ratio Tom mentioned can vary i.e. 15/16th, 7/8th, 3/4th, depending on just how far from the masthead the forestay is terminated. The advantage for fractional rigged boats it that the jib is smaller for a given boat size. Makes for easier handling. The mains are generally larger. When it come to Roach, if you were to draw a straight line from the head of your mainsail to the clew, all of the sail area aft of that line is the roach. The roach would fold over and be useless if it wasn't supported by the battens. An extreme example of roach is the IACC class (America's Cup) boats. The opposite extreme (no roach) is a mainsail that is furled in the mast. These mains have can have no roach because there are no battens to support the roach. Rodney Kidd C-38 #297, Flying Bear
Gary, Tom is correct. A fractional rig is one in which the forestay does not go to the masthead but is rigged some distance below. Later Hunters are fractionaly rigged, most Catalina's are not. The ratio Tom mentioned can vary i.e. 15/16th, 7/8th, 3/4th, depending on just how far from the masthead the forestay is terminated. The advantage for fractional rigged boats it that the jib is smaller for a given boat size. Makes for easier handling. The mains are generally larger. When it come to Roach, if you were to draw a straight line from the head of your mainsail to the clew, all of the sail area aft of that line is the roach. The roach would fold over and be useless if it wasn't supported by the battens. An extreme example of roach is the IACC class (America's Cup) boats. The opposite extreme (no roach) is a mainsail that is furled in the mast. These mains have can have no roach because there are no battens to support the roach. Rodney Kidd C-38 #297, Flying Bear
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Justin - O'day Owners' Web
Roach
One of the advantages to fractional rigs is that the top of the mast, above the forestay, can be made to bend. This allows air to dump from the top of the sail in puffs. A 17/18 rig won't don much for you in this regard, but even a 7/8 will do a bit. What many of us refer to as full-roach (myself included) is not quite accurate, at least according to my local loft (Hallet Sails, Falmouth). According to them and corroborated by a bunch of Farrier sailors in my area, a true full roach sail would come aft from the mast head horizontally until it made a constant radius curve directly about the end of the boom; the trailing edge would then be vertical. In reality, I've never seen a rig like this, but I have seen lots of performance cats, and some monohulls (HC50 comes to mind) that come close. The clear advantage is lots more sailarea, though a backstay will become an issue. This is why the boats you see lots of roach on typically have swept shrouds without a backstay, or running backs. The second advantage is in the cleaner exit as the sail moves through the wind. Sharp points on foils (wings, sails, keels) leave massive wingtip voriticies as they cut through the fluid through which they are creating lift. This is why the sharp pointed keels of the seventies have been largely done away with and been replaced with either more rounded shapes or with winglets (similar to modern aircraft) I've read that the drag created by wingtip vortex can be up to 30% of the total lift generated; cleaner airflow = more powe. Justin - O'day Owners' Web
One of the advantages to fractional rigs is that the top of the mast, above the forestay, can be made to bend. This allows air to dump from the top of the sail in puffs. A 17/18 rig won't don much for you in this regard, but even a 7/8 will do a bit. What many of us refer to as full-roach (myself included) is not quite accurate, at least according to my local loft (Hallet Sails, Falmouth). According to them and corroborated by a bunch of Farrier sailors in my area, a true full roach sail would come aft from the mast head horizontally until it made a constant radius curve directly about the end of the boom; the trailing edge would then be vertical. In reality, I've never seen a rig like this, but I have seen lots of performance cats, and some monohulls (HC50 comes to mind) that come close. The clear advantage is lots more sailarea, though a backstay will become an issue. This is why the boats you see lots of roach on typically have swept shrouds without a backstay, or running backs. The second advantage is in the cleaner exit as the sail moves through the wind. Sharp points on foils (wings, sails, keels) leave massive wingtip voriticies as they cut through the fluid through which they are creating lift. This is why the sharp pointed keels of the seventies have been largely done away with and been replaced with either more rounded shapes or with winglets (similar to modern aircraft) I've read that the drag created by wingtip vortex can be up to 30% of the total lift generated; cleaner airflow = more powe. Justin - O'day Owners' Web
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R.W.Landau
Tom is right
A jib that is hauled to the mast below the mast head is a fractional. The percentage is where the block is located. 7/8ths, 3/4 etc. r.w.landau
A jib that is hauled to the mast below the mast head is a fractional. The percentage is where the block is located. 7/8ths, 3/4 etc. r.w.landau
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Pete
Another question
Now that we're talking about roaches and fractional jibs, does anyone know why some boats have relatively small mains with large, overlapping genoas (e.g., Catalinas) while others have large roach mains with relatively small, non-overlapping fractional jibs (e.g., Freedoms, w/ free-standing carbon masts)? I thought that the overlapping sail arrangement of the former gave the *slot effect* that increased lift. On the other hand, the latter gives you a self-tacking jib which simplifies sail handling. What is the theory behind these different approaches?
Now that we're talking about roaches and fractional jibs, does anyone know why some boats have relatively small mains with large, overlapping genoas (e.g., Catalinas) while others have large roach mains with relatively small, non-overlapping fractional jibs (e.g., Freedoms, w/ free-standing carbon masts)? I thought that the overlapping sail arrangement of the former gave the *slot effect* that increased lift. On the other hand, the latter gives you a self-tacking jib which simplifies sail handling. What is the theory behind these different approaches?
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Gary Wyngarden
Dummy!
Don't you know anything? A sil is what goes below the window, oops I mean porthole. I always keep mine in a locker so no one steals them.
Don't you know anything? A sil is what goes below the window, oops I mean porthole. I always keep mine in a locker so no one steals them.
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