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Sailing Newbie Question
I am learning to sail and have a few questions. I understand that the
sails can act either as an airofoil (lile an aircraft wing) or like a parachute where the wind simply blows the sail directly. My question is this. If the wind is ahead of the beam ie we are sailing windward then I expect that the airofoil principle must always hold there otherwise we would be sailing backwards! However, if the wind is aft of the beam on say the starboard side then surely we have a choice where to set the sails ie they can be on the starboard side (ie the boom is pointing to the starboard side) where they act as an airofoil or on the port side where they act as a 'parachute' - is this right or am I missing something. If so which is best? Thanks |
Very perceptive. However, when off the wind on most boats, the
rigging disallows the positioning of the sails to act as an airfoil. CN "Love a Sheep" wrote in message om... I am learning to sail and have a few questions. I understand that the sails can act either as an airofoil (lile an aircraft wing) or like a parachute where the wind simply blows the sail directly. My question is this. If the wind is ahead of the beam ie we are sailing windward then I expect that the airofoil principle must always hold there otherwise we would be sailing backwards! However, if the wind is aft of the beam on say the starboard side then surely we have a choice where to set the sails ie they can be on the starboard side (ie the boom is pointing to the starboard side) where they act as an airofoil or on the port side where they act as a 'parachute' - is this right or am I missing something. If so which is best? Thanks |
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"Peter Bennett" wrote in message
news.com... On 21 Nov 2004 12:18:14 -0800, (Love a Sheep) wrote: I am learning to sail and have a few questions. I understand that the sails can act either as an airofoil (lile an aircraft wing) or like a parachute where the wind simply blows the sail directly. My question is this. If the wind is ahead of the beam ie we are sailing windward then I expect that the airofoil principle must always hold there otherwise we would be sailing backwards! True However, if the wind is aft of the beam on say the starboard side then surely we have a choice where to set the sails ie they can be on the starboard side (ie the boom is pointing to the starboard side) where they act as an airofoil or on the port side where they act as a 'parachute' - is this right or am I missing something. If so which is best? No. If the wind is from starboard, and abaft the beam, the sails will not normally stay out to starboard, as the sheets are rigged to pull the boom (and jib) into the boat. It is possible with the wind very nearly dead astern to have the main and jib on opposite sides - this usually works best with the wind slightly to the same side as the boom. This is called "sailing by the lee", and will lead to an accidental jibe if you let the wind get too far to the same side as the boom (then you will find out why it is called a boom :-( ) For either the slow, stupid, or stunned, it's called the boom boom. |
Using the sail's trailing edge as a leading edge is problematic.
They will not be efficient this way - tantamount to running an airplane wing backwards. Letting them out on the port side however would work provided you could let them out that far without fouling the rigging. CN "Love a Sheep" wrote in message om... I am learning to sail and have a few questions. I understand that the sails can act either as an airofoil (lile an aircraft wing) or like a parachute where the wind simply blows the sail directly. My question is this. If the wind is ahead of the beam ie we are sailing windward then I expect that the airofoil principle must always hold there otherwise we would be sailing backwards! However, if the wind is aft of the beam on say the starboard side then surely we have a choice where to set the sails ie they can be on the starboard side (ie the boom is pointing to the starboard side) where they act as an airofoil or on the port side where they act as a 'parachute' - is this right or am I missing something. If so which is best? Thanks |
On Sun, 21 Nov 2004 12:18:14 -0800, Love a Sheep wrote:
I am learning to sail and have a few questions. I understand that the sails can act either as an airofoil (lile an aircraft wing) or like a parachute where the wind simply blows the sail directly. My question is this. If the wind is ahead of the beam ie we are sailing windward then I expect that the airofoil principle must always hold there otherwise we would be sailing backwards! However, if the wind is aft of the beam on say the starboard side then surely we have a choice where to set the sails ie they can be on the starboard side (ie the boom is pointing to the starboard side) where they act as an airofoil or on the port side where they act as a 'parachute' - is this right or am I missing something. If so which is best? Thanks You've already got a lot of good answers. I'll just point out one more thing which is that the two sails on a boat interact. That is, even when the wind is aft of abeam, the wind flowing over the main may be dead abeam or so, because the jib or spinnaker changes the direction of flow. --Mac |
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Capt. Neal® writes: Poor fellow! The man lost his life primarily because of poor design by the naval architect. Those C&Cs are a death trap in more than one way it seems. But, to design a cruising boat with a boom so low that it can smack you up side the head is criminal. I should think a nice little lawsuit would straighten out C&C and the negligent designer. You won't find a Wm. Tripp Jr. designed cruiser with such flaws. CN R. Actually, you will. I have a Columbia 32, designed by none other than William Tripp Jr, and the boom sweeps over the cockpit definitely below head-height. At least if I have the 'flattening reef' in the main out (I think there is a fancier name for it but I forgot it). If I have inexperienced crew, I sometimes put the flattening reef in even in light airs so that the boom is a half-foot higher and less dangerous. --Ernst Columbia 32 #25 'Tavernier' |
On Sun, 21 Nov 2004 16:30:46 -0800, "Jonathan Ganz"
wrote: For either the slow, stupid, or stunned, it's called the boom boom. We had a regatta in my club in 2001 during which a fellow was killed via "boom boom". A storm front went through creating 50 knot winds that...unusually...stayed at 30-35 knots most of the day even as the sun came out. During the races, a poor ******* got clipped in the head...hard...during a crash jib (no preventers or concept of "duck", I assume). He failed to fall down and got smashed on the opposite side of the head a couple of seconds later. They pulled the plug on him after a week in a flatline coma. Even though I recall the boat was a C&C 29, the motion was so fast and hard that even that boat's 10 foot boom had enough velocity to crunch a skull. So use preventers and watch sea-state roll in downwind situations. R. |
Poor fellow! The man lost his life primarily because
of poor design by the naval architect. Those C&Cs are a death trap in more than one way it seems. But, to design a cruising boat with a boom so low that it can smack you up side the head is criminal. I should think a nice little lawsuit would straighten out C&C and the negligent designer. You won't find a Wm. Tripp Jr. designed cruiser with such flaws. CN "rhys" wrote in message ... On Sun, 21 Nov 2004 16:30:46 -0800, "Jonathan Ganz" wrote: For either the slow, stupid, or stunned, it's called the boom boom. We had a regatta in my club in 2001 during which a fellow was killed via "boom boom". A storm front went through creating 50 knot winds that...unusually...stayed at 30-35 knots most of the day even as the sun came out. During the races, a poor ******* got clipped in the head...hard...during a crash jib (no preventers or concept of "duck", I assume). He failed to fall down and got smashed on the opposite side of the head a couple of seconds later. They pulled the plug on him after a week in a flatline coma. Even though I recall the boat was a C&C 29, the motion was so fast and hard that even that boat's 10 foot boom had enough velocity to crunch a skull. So use preventers and watch sea-state roll in downwind situations. R. |
Just ignore crapton.
That sounds rough... Sounds like a combination of bad judgement on the part of the skipper and the guy who got hit. We typically sail in 25+ kts, and rarely use a preventer unless we're going to have a long downwind run. We don't race though. -- "j" ganz @@ www.sailnow.com "rhys" wrote in message ... On Sun, 21 Nov 2004 16:30:46 -0800, "Jonathan Ganz" wrote: For either the slow, stupid, or stunned, it's called the boom boom. We had a regatta in my club in 2001 during which a fellow was killed via "boom boom". A storm front went through creating 50 knot winds that...unusually...stayed at 30-35 knots most of the day even as the sun came out. During the races, a poor ******* got clipped in the head...hard...during a crash jib (no preventers or concept of "duck", I assume). He failed to fall down and got smashed on the opposite side of the head a couple of seconds later. They pulled the plug on him after a week in a flatline coma. Even though I recall the boat was a C&C 29, the motion was so fast and hard that even that boat's 10 foot boom had enough velocity to crunch a skull. So use preventers and watch sea-state roll in downwind situations. R. |
Love the name of your boat. There is a town in the Keys with that name, BTW.
What's your boom doing so low? Check the mast and look for an old, faded- out black line. This should be where the boom is located. Chances are somebody lowered the boom and increased the mainsail size. There is no reason on that 32-footer why the boom is sweeping the cockpit at less than head height. To make things safer for yourself either raise the boom to specs or install a sit-under bimini which makes it impossible for you to get your head smacked by the boom. You may even have the wrong mainsail on that boat. Check the specs on the original and measure yours against it. It could be the leech is longer which some racers do to lower the end of the boom. Check out my website for a few pictures of a bimini which is made to sit under. However, even with the bimini laid down the boom is high enough not to smack someone upside the head. If you have a boat with such obvious dangers it is smart to get rid of them one way or the other before they do you in. Listen to a man with impeccable credentials and years of experience. Capt. Neal USCG Master, Near Shore, 25GT also Operator Uninspected Passenger Vessels, Near Shore http://captneal.homestead.com/index.html wrote in message ... Capt. Neal® writes: Poor fellow! The man lost his life primarily because of poor design by the naval architect. Those C&Cs are a death trap in more than one way it seems. But, to design a cruising boat with a boom so low that it can smack you up side the head is criminal. I should think a nice little lawsuit would straighten out C&C and the negligent designer. You won't find a Wm. Tripp Jr. designed cruiser with such flaws. CN R. Actually, you will. I have a Columbia 32, designed by none other than William Tripp Jr, and the boom sweeps over the cockpit definitely below head-height. At least if I have the 'flattening reef' in the main out (I think there is a fancier name for it but I forgot it). If I have inexperienced crew, I sometimes put the flattening reef in even in light airs so that the boom is a half-foot higher and less dangerous. --Ernst Columbia 32 #25 'Tavernier' |
"Capt. Neal®" wrote in message ... Love the name of your boat. There is a town in the Keys with that name, BTW. What's your boom doing so low? Check the mast and look for an old, faded- out black line. This should be where the boom is located. Chances are somebody lowered the boom and increased the mainsail size. There is no reason on that 32-footer why the boom is sweeping the cockpit at less than head height. I thought you had walked the plank somewhere! Anyway, the Mirage 33 I crewed on for 4 years had a boom that was about 6' 1" off the cockpit sole. When I got hit, it was because I was standing on the seat trying to stow away excess halyard line and I made the mistake of letting the skipper control the ship's wheel. |
On Mon, 22 Nov 2004 14:56:43 -0500, Capt. Neal®
wrote: Poor fellow! The man lost his life primarily because of poor design by the naval architect. Actually, probably poor instruction from the skipper, but it was rough enough that he might simply have been "thrown upright" to catch his balance and got clipped. I don't know the fine details, only that he got "boomed" on both sides of his head, with the second one basically mushing his brain. Those C&Cs are a death trap in more than one way it seems. I own a C&C design and I find them quite safe. I will cop to the crappy cored decks, however...but they can be remedied. But, to design a cruising boat with a boom so low that it can smack you up side the head is criminal. I should think a nice little lawsuit would straighten out C&C and the negligent designer. Too late. Company was sold 15 years ago although the trademark lingers. You won't find a Wm. Tripp Jr. designed cruiser with such flaws. If you say so... R. |
On Mon, 22 Nov 2004 13:30:55 -0800, "Jonathan Ganz"
wrote: Just ignore crapton. That sounds rough... It was. A couple were drowned when their catamaran flipped down by Windsor in the same wind front. Several boats were damaged (it was a C&C regatta) and I saw a 41 footer attempt to get inside our basin at the height of it...the water was pouring OUT of the basin so fast they had to come about and run out into the lake. Sounds like a combination of bad judgement on the part of the skipper and the guy who got hit. Or he was 6' 2". The seas were high and got higher all day as the wind swung west. Even at dock it was reading 35 knots...we stayed in due to traffic and my wife's advanced state of pregnancy. We typically sail in 25+ kts, and rarely use a preventer unless we're going to have a long downwind run. We don't race though. I rig preventers frequently but leave them slack unless conditions warrant it. But then I sail my 33 footer solo a lot and I am about one inch taller than the boom end if the mainsheet is taut. R. |
"Don White" writes: "Capt. Neal®" wrote in message ... Love the name of your boat. There is a town in the Keys with that name, BTW. What's your boom doing so low? Check the mast and look for an old, faded- out black line. This should be where the boom is located. Chances are somebody lowered the boom and increased the mainsail size. There is no reason on that 32-footer why the boom is sweeping the cockpit at less than head height. looks like I'll have to do some usenet archaeology. I presume that the first part of this posting is a reply to my own posting. Only I never saw that reply even though I have read usenet at least twice a day since I posted. Anyway, I did not choose the name of my boat ('Tavernier') but I do like it, too. And yes, I know that there is a community called Tavernier in the Fla. Keys. I know very little of my boat's history (bought her when she was 25 years old to the month) but there are some indications that she spent a lot of time in Florida. If you really want to know mo the island of Tavernier was probably named after Bertrand Tavernier, a quite famous French guy who explored much of Florida in the 1400s or 1500s. Literally, it translates to 'bartender' (someone who has a taverne). Anyway, that's an interesting thought, that someone lowered the boom to increase sail area. The PO was very much into racing and I could see him doing this. Next time at the boat (this weekend, probably), I will definitively look for a 'faded black line' or any other indication that the boom was lowered. But wouldn't lowering the boom leave a lot more physical evidence than a faded black line; like holes in the mast where the gooseneck fitting was attached previously etc? --Ernst |
wrote in message ... "Don White" writes: "Capt. Neal®" wrote in message ... Love the name of your boat. There is a town in the Keys with that name, BTW. What's your boom doing so low? Check the mast and look for an old, faded- out black line. This should be where the boom is located. Chances are somebody lowered the boom and increased the mainsail size. There is no reason on that 32-footer why the boom is sweeping the cockpit at less than head height. looks like I'll have to do some usenet archaeology. I presume that the first part of this posting is a reply to my own posting. Only I never saw that reply even though I have read usenet at least twice a day since I posted. Anyway, I did not choose the name of my boat ('Tavernier') but I do like it, too. And yes, I know that there is a community called Tavernier in the Fla. Keys. I know very little of my boat's history (bought her when she was 25 years old to the month) but there are some indications that she spent a lot of time in Florida. If you really want to know mo the island of Tavernier was probably named after Bertrand Tavernier, a quite famous French guy who explored much of Florida in the 1400s or 1500s. Literally, it translates to 'bartender' (someone who has a taverne). Anyway, that's an interesting thought, that someone lowered the boom to increase sail area. The PO was very much into racing and I could see him doing this. Next time at the boat (this weekend, probably), I will definitively look for a 'faded black line' or any other indication that the boom was lowered. But wouldn't lowering the boom leave a lot more physical evidence than a faded black line; like holes in the mast where the gooseneck fitting was attached previously etc? --Ernst Depends on the gooseneck fitting. Mine is a sliding gooseneck that can be raised or lowered at will. Oftentimes the gooseneck will fit an internal track in the mast and although it may have been riveted on to begin with it is a simple matter to drill out the rivets and change the location while adding new rivets. This would leave holes in the mast to show that it was done, however. More likely is a mainsail cut to lower the boom on the aft end by increasing the length of the leech on the mainsail. This would result in the aft end of the boom being lower than the forward end. The original sail held the boom horizontal, I'm sure. I heard a different story about Tavernier. At one time it was a busy port for exporting pineapples, hardwood, and vegetables. There were several taverns available for the workers. Word got out that there was always a tavern near the port . Then the Frenchies came along and changed the spelling. Your explanation sounds more plausible. CN |
Capt. Neal® wrote:
Depends on the gooseneck fitting. Mine is a sliding gooseneck that can be raised or lowered at will. Oftentimes the gooseneck will fit an internal track in the mast and although it may have been riveted on to begin with it is a simple matter to drill out the rivets and change the location while adding new rivets. This would leave holes in the mast to show that it was done, however. I believe the gooseneck was riveted to the mast on this vessel when originally manufactured More likely is a mainsail cut to lower the boom on the aft end by increasing the length of the leech on the mainsail. This would result in the aft end of the boom being lower than the forward end. The original sail held the boom horizontal, I'm sure. What sort of racing allows modifcation of the main so as to increase area beyond the manufactures specifications? Cheers Marty |
"Martin Baxter" wrote in message ... What sort of racing allows modifcation of the main so as to increase area beyond the manufactures specifications? Don't ask me. I hate yacht racing. I do know some racers will embrace any and all cheats they think they can get away with. CN |
Martin Baxter wrote: What sort of racing allows modifcation of the main so as to increase area beyond the manufactures specifications? More roach. Cheers |
Capt. Neal® writes:
Depends on the gooseneck fitting. Mine is a sliding gooseneck that can be raised or lowered at will. Oftentimes the gooseneck will fit an internal track in the mast and although it may have been riveted on to begin with it is a simple matter to drill out the rivets and change the location while adding new rivets. This would leave holes in the mast to show that it was done, however. More likely is a mainsail cut to lower the boom on the aft end by increasing the length of the leech on the mainsail. This would result in the aft end of the boom being lower than the forward end. The original sail held the boom horizontal, I'm sure. Good points, all. I actually do think that my boom 'droops' quite a bit so your theory of the too-long-leech has a lot for it. The sail is definitively not original (the boat will be feting its 30th birthday soon...). I heard a different story about Tavernier. At one time it was a busy port for exporting pineapples, hardwood, and vegetables. There were several taverns available for the workers. Word got out that there was always a tavern near the port . Then the Frenchies came along and changed the spelling. Your explanation sounds more plausible. Yes, I think so. Good story, though. --Ernst |
Martin Baxter writes: Capt. Neal® wrote: Depends on the gooseneck fitting. Mine is a sliding gooseneck that can be raised or lowered at will. Oftentimes the gooseneck will fit an internal track in the mast and although it may have been riveted on to begin with it is a simple matter to drill out the rivets and change the location while adding new rivets. This would leave holes in the mast to show that it was done, however. I believe the gooseneck was riveted to the mast on this vessel when originally manufactured I believe so, too (it is definitely not on a rail or track) but will check next time at the boat (weekend). --Ernst |
Capt. Neal® wrote in message ...
Poor fellow! The man lost his life primarily because of poor design by the naval architect. Those C&Cs are a death trap in more than one way it seems. But, to design a cruising boat with a boom so low that it can smack you up side the head is criminal. I should think a nice little lawsuit would straighten out C&C and the negligent designer. You won't find a Wm. Tripp Jr. designed cruiser with such flaws. CN I' d have to disagree about the poor design by the naval architect statement - only because there are many an older cruising boat that don't have the benefit or newer design of today's taller rigs, so they indeed have a lower (and longer) boom than one's head might prefer in an accidental jibe. My 1969 Morgan 33 Classic was one helluva boat for instance, but indeed, the boom was low enough to clobber you if you weren't careful. When it came to design, Charley knew/knows his stuff. I would suspect he expected those that were sailing his boats to know theirs, too. Anyway, I'd say if you had to place blame, it was negligence on the skipper's part, and the poor guy that got knocked. Beyond that, what can you do? Accidents do indeed happen. Sometimes with very unfortunate and dire consequences. Capt. Rob Welling Sarasota, FL |
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The airfoil is there in all cases, in this respect; as the sail aqttacks the
wind, reguardless of the angle, some air flows on both sides of the sail. Wind flowing over the most leeward side of the sail creates a partial vacume on that side, so with air pressure stronger on one side the sail is "pushed" or "drawn" to the direction where the low pressure is. Even with the wind directly astern, a low pressure is created on the front of the sail, and the sail(boat) is drawn forward. Hope that is as clear as I mean it to be. Welcome to the intoxicaion of sailing. Dave Hord. |
On Wed, 09 Feb 2005 08:49:14 GMT, "DAVE HORD"
scribbled thusly: The airfoil is there in all cases, in this respect; as the sail aqttacks the wind, reguardless of the angle, some air flows on both sides of the sail. Wind flowing over the most leeward side of the sail creates a partial vacume on that side, so with air pressure stronger on one side the sail is "pushed" or "drawn" to the direction where the low pressure is. Even with the wind directly astern, a low pressure is created on the front of the sail, and the sail(boat) is drawn forward. Hope that is as clear as I mean it to be. Welcome to the intoxicaion of sailing. Dave Hord. OK, that's Bernoulli. Now I'd suggest you look into Newtonian explanation of lift ie deflection. Oz1...of the 3 twins. I welcome you to crackerbox palace,We've been expecting you |
It is a simple matter to derive "Bernoulli" using Newtonian equations and
principals. They are the same thing. One common mistake people have with Bernoulli is using scalar speed and not vector velocity. If you use scalar speed, Bernoulli is then only valid in "one" dimensional flow like that approximated in pipes. Pipe flow observations is what Bernoulli used to formulate his equations. Mark "Capt. Mooron" wrote in message news:bqKOd.17903$K54.4882@edtnps84... On Wed, 09 Feb 2005 08:49:14 GMT, "DAVE HORD" scribbled thusly: The airfoil is there in all cases, in this respect; as the sail aqttacks the wind, reguardless of the angle, some air flows on both sides of the sail. Wind flowing over the most leeward side of the sail creates a partial vacume on that side, so with air pressure stronger on one side the sail is "pushed" or "drawn" to the direction where the low pressure is. Even with the wind directly astern, a low pressure is created on the front of the sail, and the sail(boat) is drawn forward. Hope that is as clear as I mean it to be. Welcome to the intoxicaion of sailing. Dave Hord. OK, that's Bernoulli. Now I'd suggest you look into Newtonian explanation of lift ie deflection. Oz1...of the 3 twins. I welcome you to crackerbox palace,We've been expecting you |
Hmm, I still have that High school graduation project I did a few years
back. I explained in it how most of that works and a couple other things with vector format and diagrams. If anyone wants it just email me. "plugster" wrote in message nk.net... It is a simple matter to derive "Bernoulli" using Newtonian equations and principals. They are the same thing. One common mistake people have with Bernoulli is using scalar speed and not vector velocity. If you use scalar speed, Bernoulli is then only valid in "one" dimensional flow like that approximated in pipes. Pipe flow observations is what Bernoulli used to formulate his equations. Mark "Capt. Mooron" wrote in message news:bqKOd.17903$K54.4882@edtnps84... On Wed, 09 Feb 2005 08:49:14 GMT, "DAVE HORD" scribbled thusly: The airfoil is there in all cases, in this respect; as the sail aqttacks the wind, reguardless of the angle, some air flows on both sides of the sail. Wind flowing over the most leeward side of the sail creates a partial vacume on that side, so with air pressure stronger on one side the sail is "pushed" or "drawn" to the direction where the low pressure is. Even with the wind directly astern, a low pressure is created on the front of the sail, and the sail(boat) is drawn forward. Hope that is as clear as I mean it to be. Welcome to the intoxicaion of sailing. Dave Hord. OK, that's Bernoulli. Now I'd suggest you look into Newtonian explanation of lift ie deflection. Oz1...of the 3 twins. I welcome you to crackerbox palace,We've been expecting you |
Sebastian Miles wrote:
Hmm, I still have that High school graduation project I did a few years back. I explained in it how most of that works and a couple other things with vector format and diagrams. If anyone wants it just email me. Sure, I'd like to see it. (email sent) DSK |
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