What is the best vmg strategy for the following circumstance? A light displacement boat is close hauled, with a 110 jib and main up. There are waves and the boat is heeling excessively during brief and prolonged gusts. Do you: 1: head up, ease mainsheet, feather to depower and reduce heel, then start back down. 2: head down, ease mainsheet, putting drive more forward to reduce heel, then start back up.
- Status
If I did not reef, which sounds like the best option,
but may not be if racing and close to the finish...I would do a variant of option 1. I'm still pretty new...but I don't think I would head up AND ease the mainsail. I prefer to feather if my goal is upwind, and a tight, flat main does better in high wind than a losser curved one. Having said that I have had to ease the mainsail when feathering curbs momentum too much, which, always precious, becomes even more important when significant waves are involved. If I am having to ease my mainsail too much to diminish heeling then it's time to heave to and reef the main... Another option I have done in heavy winds (when you may want a smaller or storm jib but don't have it) is to lower the jib and sail that baby like a sunfish with a flat full main! It works on my boat but would not be as ideal as reefing if the large jib didn't overpower you. Though not a newbie, I've only been sailing for a few years, and my thoughts are based mostly on my personal experience with little books/veteran advice...
but may not be if racing and close to the finish...I would do a variant of option 1. I'm still pretty new...but I don't think I would head up AND ease the mainsail. I prefer to feather if my goal is upwind, and a tight, flat main does better in high wind than a losser curved one. Having said that I have had to ease the mainsail when feathering curbs momentum too much, which, always precious, becomes even more important when significant waves are involved. If I am having to ease my mainsail too much to diminish heeling then it's time to heave to and reef the main... Another option I have done in heavy winds (when you may want a smaller or storm jib but don't have it) is to lower the jib and sail that baby like a sunfish with a flat full main! It works on my boat but would not be as ideal as reefing if the large jib didn't overpower you. Though not a newbie, I've only been sailing for a few years, and my thoughts are based mostly on my personal experience with little books/veteran advice...
What I would try...
Without knowing what type of boat, put twist in the sails by moving jibsheet fairleads back, easing mainsheet a little & pulling traveler up. Flatten main as much as possible with backstay & outhaul. Keep draft forward in the main with cunningham. In general, head up a little going up a wave & down a little down the backside, to avoid flopping off the top of the wave. If crew is available, ease traveler in puffs, otherwise feather up.
Without knowing what type of boat, put twist in the sails by moving jibsheet fairleads back, easing mainsheet a little & pulling traveler up. Flatten main as much as possible with backstay & outhaul. Keep draft forward in the main with cunningham. In general, head up a little going up a wave & down a little down the backside, to avoid flopping off the top of the wave. If crew is available, ease traveler in puffs, otherwise feather up.
Instead of feathering, try a fisherman's
reef. That means luff the main a bit by either dropping the traveler or letting out mainsheet or both, while still using a powered up jib.
reef. That means luff the main a bit by either dropping the traveler or letting out mainsheet or both, while still using a powered up jib.
I like Sandy's solution first but I would
take the traveller even more to weather and hold the boom down with the boom vang . The boom will flex a bit in the puffs and ease the leach. A twist is what you want in your sails anyway in waves so some part of the sail has power as the mast pitches forward and back. If after twisting off your sails you are overpowered, its time to reef as suggested by Stu, but still trim with a twist. Close hauled is that point on your VMG diagram that you are fastest in the "Y" (or upwind) direction. it is generally around 45 degrees off the true wind, but varies with each boat, each sail combination, each sea combination and every wind speed. No one here can tell you what that is for your conditions, but if you're close hauled, then stay close hauled. Some ultra lights have to foot off in waves for fear of staving in the bow as it drives through at high speed, and you may foot off a bit as suggested by Phil for comfort. But that won't be the fastest.
take the traveller even more to weather and hold the boom down with the boom vang . The boom will flex a bit in the puffs and ease the leach. A twist is what you want in your sails anyway in waves so some part of the sail has power as the mast pitches forward and back. If after twisting off your sails you are overpowered, its time to reef as suggested by Stu, but still trim with a twist. Close hauled is that point on your VMG diagram that you are fastest in the "Y" (or upwind) direction. it is generally around 45 degrees off the true wind, but varies with each boat, each sail combination, each sea combination and every wind speed. No one here can tell you what that is for your conditions, but if you're close hauled, then stay close hauled. Some ultra lights have to foot off in waves for fear of staving in the bow as it drives through at high speed, and you may foot off a bit as suggested by Phil for comfort. But that won't be the fastest.
Play the traveller !!!
For BEST VMG its usually best to 'play' the traveller so that the boat stays at constant heel. This requires a tight vang, *board-flat sails* (unless you need draft to 'punch' through steep waves) and a quick response on the traveller .... all the while the mainsheet is left alone but ready to be released if totally overpowered. Sometimes called 'blading-out' the main. The only limitations is when the boat goes much above its 'hull speed' and is heeled over (usually beyond 30% heel) and the 'bite' of the keel (by trigonometry) is less .... and the boat begins to 'skid' off to leeward. If you see a drop in VMG when the boat is 'over' ... the first question should be: is the boat 'skidding off to leeward' (as you watch the angle of the stern wake, comparing it to 'normal'). Feathering will slow the boat down making it more vulnerable to gusts, Bearing off (on a keel boat) needs a loose vang to depower the upper sections of the mainsail but can make the boat 'cranky' when the winds are 'unstable' (rolling, etc.). In all these techniques the goal is to keep the boat 'moving' and should be done with a FULL set of telltales so that you can SEE whats going on with the airflow across the sails. Without telltales you can insure that you have some 'modicum' of attached flow at all times so that you maintain control. If you are in 'boisterous' condition and lose airflow attachment .... expect to get a 'pasting' when the flow suddenly reattaches to the sails. For Racing and to get best VMG one usually drops the traveller in a heavy gust, then pinches up slightly during the lulls to gain distance TO weather using the momentum gained by accelerating during the 'blade-out'. Also for racing (beating) vs. VMG ... best VMG is usually gained at the *beginning* of windward leg by playing the traveller but then 'pinching-up' at/near the end of a leg (before tacking onto the next leg) .... all due to the magic of 'trigonometry'. Of course you will never ever experience the exact same conditions of wind speed and wave formation every time .... therefore all the above is 'generalized' and only using a GPS set to VMG function to a 'waypoint' (real or imaginary) will get you to optimized VMG. Making the sails flatter and flatter is usually the best rather than reefing, Usually when the boat starts to radically 'skid off to leeward' with already FLAT sails and you get drop in VMG (on the GPS) is when you reef. Also you want to "S-curve" up the faces of oncoming waves so that the bow doesnt 'plunge' into the trough of an upcoming wave, thus slowing the boat and losing VMG. For optimum VMG its really best to use the VMG function on a GPS towards an imaginary waypoint at the end of the leg, then carefully 'test' all the 'techniques' to arrive at whats best for optimal VMG .... and thats going to be different EVERY time you go out, so dont get 'locked down' with one specific method.
For BEST VMG its usually best to 'play' the traveller so that the boat stays at constant heel. This requires a tight vang, *board-flat sails* (unless you need draft to 'punch' through steep waves) and a quick response on the traveller .... all the while the mainsheet is left alone but ready to be released if totally overpowered. Sometimes called 'blading-out' the main. The only limitations is when the boat goes much above its 'hull speed' and is heeled over (usually beyond 30% heel) and the 'bite' of the keel (by trigonometry) is less .... and the boat begins to 'skid' off to leeward. If you see a drop in VMG when the boat is 'over' ... the first question should be: is the boat 'skidding off to leeward' (as you watch the angle of the stern wake, comparing it to 'normal'). Feathering will slow the boat down making it more vulnerable to gusts, Bearing off (on a keel boat) needs a loose vang to depower the upper sections of the mainsail but can make the boat 'cranky' when the winds are 'unstable' (rolling, etc.). In all these techniques the goal is to keep the boat 'moving' and should be done with a FULL set of telltales so that you can SEE whats going on with the airflow across the sails. Without telltales you can insure that you have some 'modicum' of attached flow at all times so that you maintain control. If you are in 'boisterous' condition and lose airflow attachment .... expect to get a 'pasting' when the flow suddenly reattaches to the sails. For Racing and to get best VMG one usually drops the traveller in a heavy gust, then pinches up slightly during the lulls to gain distance TO weather using the momentum gained by accelerating during the 'blade-out'. Also for racing (beating) vs. VMG ... best VMG is usually gained at the *beginning* of windward leg by playing the traveller but then 'pinching-up' at/near the end of a leg (before tacking onto the next leg) .... all due to the magic of 'trigonometry'. Of course you will never ever experience the exact same conditions of wind speed and wave formation every time .... therefore all the above is 'generalized' and only using a GPS set to VMG function to a 'waypoint' (real or imaginary) will get you to optimized VMG. Making the sails flatter and flatter is usually the best rather than reefing, Usually when the boat starts to radically 'skid off to leeward' with already FLAT sails and you get drop in VMG (on the GPS) is when you reef. Also you want to "S-curve" up the faces of oncoming waves so that the bow doesnt 'plunge' into the trough of an upcoming wave, thus slowing the boat and losing VMG. For optimum VMG its really best to use the VMG function on a GPS towards an imaginary waypoint at the end of the leg, then carefully 'test' all the 'techniques' to arrive at whats best for optimal VMG .... and thats going to be different EVERY time you go out, so dont get 'locked down' with one specific method.
Before I reefed
Before I reefed, I would think about how much the lulls were lulls, and just how overpowered I was in the gusts. Maybe it is our local gusts - but there are days around here when you feel like you should reef or take the reef out every minute. In our weird lake winds, it is often better to just take advice like Sandy's. No sooner do you reef than the wind is done for the day... Generally I'd want to ease the main and feather up to luff it if close hauled, but I sail a boat that can heel a lot without broaching, so if I am coming up from a close reach and get a bit more heel as I turn up before I let the main out enough, it works out OK. Different boats may well call for a different solution, especially broach-prone modern craft with their wide sterns. In our local conditions, though, and on a J22, I am reluctant to reef. If I did, the boat just dies in the big lulls - probably why the local racers seem reluctant to reef as well. OC
Before I reefed, I would think about how much the lulls were lulls, and just how overpowered I was in the gusts. Maybe it is our local gusts - but there are days around here when you feel like you should reef or take the reef out every minute. In our weird lake winds, it is often better to just take advice like Sandy's. No sooner do you reef than the wind is done for the day... Generally I'd want to ease the main and feather up to luff it if close hauled, but I sail a boat that can heel a lot without broaching, so if I am coming up from a close reach and get a bit more heel as I turn up before I let the main out enough, it works out OK. Different boats may well call for a different solution, especially broach-prone modern craft with their wide sterns. In our local conditions, though, and on a J22, I am reluctant to reef. If I did, the boat just dies in the big lulls - probably why the local racers seem reluctant to reef as well. OC
RIch
I really like your post, but it seems to require more active and knowledgeable adult crew than I generally have, or, at least, playing the traveler from the helm gets very tiring on the boat I sail. It just winds up being easier to luff up and/or sheet out - and I don't find the boat getting vulnerable to gusts. Our lake winds are very much more shifty and puffy than any ocean winds I have ever experienced, and no waves to contend with unless one counts PB wakes, so limited crew and these conditions may explain why I take an easy way out. OC
I really like your post, but it seems to require more active and knowledgeable adult crew than I generally have, or, at least, playing the traveler from the helm gets very tiring on the boat I sail. It just winds up being easier to luff up and/or sheet out - and I don't find the boat getting vulnerable to gusts. Our lake winds are very much more shifty and puffy than any ocean winds I have ever experienced, and no waves to contend with unless one counts PB wakes, so limited crew and these conditions may explain why I take an easy way out. OC
Rich H
was probably a sailor in his previous 12 lives. Very knowledgeable. If I get out and back from my boat in the dingy... I have had a good day.
was probably a sailor in his previous 12 lives. Very knowledgeable. If I get out and back from my boat in the dingy... I have had a good day.
Agreed, RichH is a man in his element.
I always learn something from each of his well thought out answers. But I am sure I'm not the only one that wants to know more about Rich personally. I find myself wondering who put him on a sailboat for the first time? When did he figure the sport was for him? Does sailing run in his family for generations? What dreams does he have for his sailing future? How about it Rich, can you share any of this with us? If personal questions are off limits, its cool but everybody cares. Lance
I always learn something from each of his well thought out answers. But I am sure I'm not the only one that wants to know more about Rich personally. I find myself wondering who put him on a sailboat for the first time? When did he figure the sport was for him? Does sailing run in his family for generations? What dreams does he have for his sailing future? How about it Rich, can you share any of this with us? If personal questions are off limits, its cool but everybody cares. Lance
Altitude a factor
OldCat, I noticed that you are in Colorado, by definition, a high altitude sailing venue. My experience is that the gusts in the mountains (Odell Lake, roughly 5200ft) are much weaker for a given wind speed than on Fern Ridge (373.5 at full pool) where I normally sail. This allows different strategies for managing sail trim than the greater forces at lower altitudes. Looking at the scenario, I was confused by "brief and prolonged wind gusts." If you are constantly having to foot off or ease your sails to avoid sailing on your ear, its probably time to think about reefing. Generally, if its time to reef, you can go faster, both through the water and VMG, if you reef. If you're ok except for occassional gusts, then just let your traveler down to ease the sail until the gust passes. Jim Kolstoe, h23 Kara's Boo
OldCat, I noticed that you are in Colorado, by definition, a high altitude sailing venue. My experience is that the gusts in the mountains (Odell Lake, roughly 5200ft) are much weaker for a given wind speed than on Fern Ridge (373.5 at full pool) where I normally sail. This allows different strategies for managing sail trim than the greater forces at lower altitudes. Looking at the scenario, I was confused by "brief and prolonged wind gusts." If you are constantly having to foot off or ease your sails to avoid sailing on your ear, its probably time to think about reefing. Generally, if its time to reef, you can go faster, both through the water and VMG, if you reef. If you're ok except for occassional gusts, then just let your traveler down to ease the sail until the gust passes. Jim Kolstoe, h23 Kara's Boo
Altitude, etc.
Rich is probably right about VMG - which was the poster's original question. I don't really know about that, I really need to get a GPS which gives that info. Still, most of the time, I am better off feathering, I'd just be exhausted if I adjusted the sails for every gust, too many gusts here. With, and when I have a friend along who is also a sailor, then we play the sails more. I really need that better GPS... As for high altitude, you are correct that the wind strength is less for a given wind speed - but we get some major wind speed. I have gone from no wind to knocked flat - in clear weather with no pesky thunderstorms about - in less than a minute. Thunderstorms are sometimes worse... I am less enthusiastic about reefing because of the huge wind variability - like I wrote, racers around here don't reef early either. The lulls are windless holes and the gusts are GUSTS. Maybe the racers push it too far - it is sometimes fun to be reefed and under control and watch the racers spinning out into broaches. I sympathize with them, though, they are going for speed and when the wind dies, and it will, shaking out a reef would probably cost them too much, so they 'chance' it. The strangest day I ever sailed in had a perfectly blue sky and no wind. I cleared the dock on a small puff and before I could get two fenders in I had to heave too under main alone and sit for two hours while Adm Beaufort's gale force streaks of foam passed by me. Then paddle back to the dock when the wind died. High altitude does not mean low force winds, you just get high enough wind speeds and you still get high force. Lake Dillon is at 9300 feet - whitecaps nearly every summer day and a reef or two ~1/3-1/2 of the afternoons. I hear Wyoming is wilder... OC
Rich is probably right about VMG - which was the poster's original question. I don't really know about that, I really need to get a GPS which gives that info. Still, most of the time, I am better off feathering, I'd just be exhausted if I adjusted the sails for every gust, too many gusts here. With, and when I have a friend along who is also a sailor, then we play the sails more. I really need that better GPS... As for high altitude, you are correct that the wind strength is less for a given wind speed - but we get some major wind speed. I have gone from no wind to knocked flat - in clear weather with no pesky thunderstorms about - in less than a minute. Thunderstorms are sometimes worse... I am less enthusiastic about reefing because of the huge wind variability - like I wrote, racers around here don't reef early either. The lulls are windless holes and the gusts are GUSTS. Maybe the racers push it too far - it is sometimes fun to be reefed and under control and watch the racers spinning out into broaches. I sympathize with them, though, they are going for speed and when the wind dies, and it will, shaking out a reef would probably cost them too much, so they 'chance' it. The strangest day I ever sailed in had a perfectly blue sky and no wind. I cleared the dock on a small puff and before I could get two fenders in I had to heave too under main alone and sit for two hours while Adm Beaufort's gale force streaks of foam passed by me. Then paddle back to the dock when the wind died. High altitude does not mean low force winds, you just get high enough wind speeds and you still get high force. Lake Dillon is at 9300 feet - whitecaps nearly every summer day and a reef or two ~1/3-1/2 of the afternoons. I hear Wyoming is wilder... OC
OldCat
Sailing successfully in the conditions you describe, I'd take my hat off to you, but a gust got it. Jim Kolstoe, h23 Kara's Boo.
Sailing successfully in the conditions you describe, I'd take my hat off to you, but a gust got it. Jim Kolstoe, h23 Kara's Boo.
Agree..
The traveler is one of the most useful tools in your quiver but the other tools should not be forgotten. Rich's description is good for the gusty conditions asked about. Light winds require a different sail trim though... If the boat is not punching the waves, without slowing, then a little belly in the main can help and again feather the helm to match the motion of the waves. This is more of a feel thing than science because if you s-curve (Rich H's description) too much you'll lose speed but if you just steer right through you will also lose speed. Feel the motion of the boat and become one with the wave motion. It's easier to feel than to describe and even easier to practice by closing your eyes (not while racing) and feeling the motion of your upper body while standing as relaxed as you can at the helm. If you're lunging forward as the boat hits a wave it's your helming needs work. Steer the boat until you have the least upper body movement fore and aft. It will be different, but similar in helm movements, depending on the size and period of the waves. This part, the helming, is as much of an art as sail trim and can take a while to get good at but it can be especially useful in rough seas once you get the hang of it..
The traveler is one of the most useful tools in your quiver but the other tools should not be forgotten. Rich's description is good for the gusty conditions asked about. Light winds require a different sail trim though... If the boat is not punching the waves, without slowing, then a little belly in the main can help and again feather the helm to match the motion of the waves. This is more of a feel thing than science because if you s-curve (Rich H's description) too much you'll lose speed but if you just steer right through you will also lose speed. Feel the motion of the boat and become one with the wave motion. It's easier to feel than to describe and even easier to practice by closing your eyes (not while racing) and feeling the motion of your upper body while standing as relaxed as you can at the helm. If you're lunging forward as the boat hits a wave it's your helming needs work. Steer the boat until you have the least upper body movement fore and aft. It will be different, but similar in helm movements, depending on the size and period of the waves. This part, the helming, is as much of an art as sail trim and can take a while to get good at but it can be especially useful in rough seas once you get the hang of it..
SCOWS !!!!!!!!!!!!!
In my younger days (1960s) as a budding new engineer I was determined to build a small catamaran with hydrofoils (combining the twin disciplines of aerodynamics and hydrodynamics). In my research I kept running across something called "the Ancient Interface" a compilation of the leading scientific articles and papers issued by NACA the predecessor of NASA. (the NACA designed foils are still accepted by boat and aero designers today). Being deep in debt from school costs, I never built the hydro cat but eventually bought an old ILYA (M16) scow from a junk pile, restored it, learned how to make my own sails, applied those principles gained from the 'ancient interface' compendium .... and started to excel in racing. My current 'favorite boat' is an old M20 Scow (fondly known as the 'submarine scow' because its so unstable and yet ultimately 'maneuverable' .. like a good fighter aircraft .. and would prefer to be upside down at all conditions. It was either learn how to sail by the 'scientific numbers' or learn how to swim. Although the old M20 has been reborn into a more modern I-20, I still get a kick pulling a water skier with my scow every now and then. You dont reef a scow, you flatten to survive; thankfully the 35 control lines are located within grasp of the helmsman on a well set up scow. With all sails up (265 sq. ft. + spinn = about 400 sq. ft.) and a 20ft. boat that is about only 625lb. and with a 'normal' heeling angle of ~30 degrees, you soon learn to master 'air flow' and sail shaping .... or you quickly are totally upside down or watch the boat instantly 'disappear' into and down below a large oncoming wave. A large scow wont pitchpole ... it will just 'sail' itself totally underwater if you hit a BIG wave wrong. My max. speed ever on my M20 was well over 25 kts. Until the advent of sailboards and radical hybrids, the scows have been the foremost 'speed demons' for the past ~100 years. Yup, most are derived from the original scows designed in the 1890s!!!!. Since I chose 'fluid and thermal sciences' as a career path, the Arvel Gentry articles for me was my 'real start' in understanding as those works were the FIRST written works that first accurately described what was actually (aerodynamically) happening with sails ... as I already knew the 'bernoulli explanation' was totally wrong because it didnt 'compute' and violated most physics/aero principals. Scows: www.ILYA.org .... you want a boat? look at the A-scow pages. Ive sailed and raced keelboats now for well over 30 years and currently sail a cutter rigged Tayana 37 out of Worton Maryland. Im currently refitting/outfitting the Tayana for a 2 year open ended voyage between Newfoundland/Labrador and the lower Caribbean ... maybe winding up in the EU for a while if the $US comes back to normal. When reflecting back one thing stands out, I learned to ask questions ... and those that replied include the top racers/crews of the various Americas Cups etc., the leading designers, the top experimentalists .... Im not bashful. Those who want to expand the 'sport' will always gladly share their knowledge if you ask them correctly. I'm just passing along what I picked up from those folks along the way. BTW - sailing fast small dinghys, doing your own boat work, making your own sails ... will greatly accelerate the 'sail learning' process. Got a question? ... just ask the GIANTS of our sport, they do answer and usually passionately share their knowledge. That is what keeps our community alive. ;-)
In my younger days (1960s) as a budding new engineer I was determined to build a small catamaran with hydrofoils (combining the twin disciplines of aerodynamics and hydrodynamics). In my research I kept running across something called "the Ancient Interface" a compilation of the leading scientific articles and papers issued by NACA the predecessor of NASA. (the NACA designed foils are still accepted by boat and aero designers today). Being deep in debt from school costs, I never built the hydro cat but eventually bought an old ILYA (M16) scow from a junk pile, restored it, learned how to make my own sails, applied those principles gained from the 'ancient interface' compendium .... and started to excel in racing. My current 'favorite boat' is an old M20 Scow (fondly known as the 'submarine scow' because its so unstable and yet ultimately 'maneuverable' .. like a good fighter aircraft .. and would prefer to be upside down at all conditions. It was either learn how to sail by the 'scientific numbers' or learn how to swim. Although the old M20 has been reborn into a more modern I-20, I still get a kick pulling a water skier with my scow every now and then. You dont reef a scow, you flatten to survive; thankfully the 35 control lines are located within grasp of the helmsman on a well set up scow. With all sails up (265 sq. ft. + spinn = about 400 sq. ft.) and a 20ft. boat that is about only 625lb. and with a 'normal' heeling angle of ~30 degrees, you soon learn to master 'air flow' and sail shaping .... or you quickly are totally upside down or watch the boat instantly 'disappear' into and down below a large oncoming wave. A large scow wont pitchpole ... it will just 'sail' itself totally underwater if you hit a BIG wave wrong. My max. speed ever on my M20 was well over 25 kts. Until the advent of sailboards and radical hybrids, the scows have been the foremost 'speed demons' for the past ~100 years. Yup, most are derived from the original scows designed in the 1890s!!!!. Since I chose 'fluid and thermal sciences' as a career path, the Arvel Gentry articles for me was my 'real start' in understanding as those works were the FIRST written works that first accurately described what was actually (aerodynamically) happening with sails ... as I already knew the 'bernoulli explanation' was totally wrong because it didnt 'compute' and violated most physics/aero principals. Scows: www.ILYA.org .... you want a boat? look at the A-scow pages. Ive sailed and raced keelboats now for well over 30 years and currently sail a cutter rigged Tayana 37 out of Worton Maryland. Im currently refitting/outfitting the Tayana for a 2 year open ended voyage between Newfoundland/Labrador and the lower Caribbean ... maybe winding up in the EU for a while if the $US comes back to normal. When reflecting back one thing stands out, I learned to ask questions ... and those that replied include the top racers/crews of the various Americas Cups etc., the leading designers, the top experimentalists .... Im not bashful. Those who want to expand the 'sport' will always gladly share their knowledge if you ask them correctly. I'm just passing along what I picked up from those folks along the way. BTW - sailing fast small dinghys, doing your own boat work, making your own sails ... will greatly accelerate the 'sail learning' process. Got a question? ... just ask the GIANTS of our sport, they do answer and usually passionately share their knowledge. That is what keeps our community alive. ;-)
RichH- As always I really appreciate your time
and I do try to pass it on as you have done. I have a friend who has had an old 18 foot Hobie Cat sitting in his backyard for over a year. A couple of times I have mentioned that we should widen the beam a bit and see if we couldn't mount some hydrofoils on it. (I was thinking it would be sort of like 2 of those Moths bolted together) Well, last Sunday he called my bluff by saying come get it and get busy. If I do start tinkering with it, I'll bug ya for some pointers. Well thank goodness Spring is marching in and dragging Summer closer. RichH I hope you have a wonderful sailing season!
and I do try to pass it on as you have done. I have a friend who has had an old 18 foot Hobie Cat sitting in his backyard for over a year. A couple of times I have mentioned that we should widen the beam a bit and see if we couldn't mount some hydrofoils on it. (I was thinking it would be sort of like 2 of those Moths bolted together) Well, last Sunday he called my bluff by saying come get it and get busy. If I do start tinkering with it, I'll bug ya for some pointers. Well thank goodness Spring is marching in and dragging Summer closer. RichH I hope you have a wonderful sailing season!
Sorry for the hijack...
Sorry for the hijack, but I thought RichH might be interested in this: http://youtube.com/watch?v=mwIl19Ptp7s International Moth (hydrofoils) in Dubai. A guy has one here in Detroit, and it's pretty amazing to watch. Resume topic...
Sorry for the hijack, but I thought RichH might be interested in this: http://youtube.com/watch?v=mwIl19Ptp7s International Moth (hydrofoils) in Dubai. A guy has one here in Detroit, and it's pretty amazing to watch. Resume topic...
A little bit of a disagreement ....
"Light winds require a different sail trim though... " They sure do ... and usually the opposite happens of what 'intuition' tells you. Very light winds dont have much energy and that makes it hard for the streamflows of light winds to stay 'attached' to the sails. Streamflows with little energy if made to radically change direction such as moving from the 'bottom/windward side' at the luff or in an attempt to follow a large full draft shape will easily 'separate'. Light winds usually require FLAT sails, just as high winds require FLAT sails ... but for different reasons. Against all intuition, light wind sailing almost always requires the same (flattened) shape as 'high wind' sailing. FAST sailing requires FLATer shaped sails. POWER sailing (punching into and through waves, etc.) requires a more full draft shape. The 'norm' of using full draft sails in light winds (a powered-up shape) will usually lead to dismal performance ... because of the enhanced potential of flow separation. Sure, coming out of a tack you need to use 'first gear' or a power shape, but unless you shift to 'high gear' or use a speed shape your boat simply wont 'go'. Flat sails in high winds depower the shape, understandable for 'survival'; but, flat sails are FAST sails and flat sails will greatly enhance light wind sailing (once you get the boat moving). The use of a full set of tell tales and a good speedo will show and validate the effects. 1st gear: powered up shape ... deeper draft 3rd gear: speed shape .... less draft and flatter shape. You can always power-up ('dropping down a gear') with deeper draft to punch through waves or accelerate out of a tack, but should go back to flat once the boat gets back up to speed. Simply watch a full set to tell tales and speedo ... as they will tell you where/how/when/why you get optimum set/shape. Light winds usually need FLAT shape or the sail easily can get into a 'separation stall' - a stall that is totally invisible to the human eyeball - because the light winds dont have enough energy to stay 'attached'. Plus, If you use a full draft shape in light winds, you'll never get out of 'first gear'. A bendy mast with radical backstay tension adjustment is the 'key' for easy/rapid powering up and down and controlling the amount of draft ... too bad such is rarely found on a cruising boat. Racers are *constantly* changing the sail shape by halyard, outhaul, vang, mast bend, etc. tensions; cruisers usually just 'raise' the sails and hope for the best. ;-)
"Light winds require a different sail trim though... " They sure do ... and usually the opposite happens of what 'intuition' tells you. Very light winds dont have much energy and that makes it hard for the streamflows of light winds to stay 'attached' to the sails. Streamflows with little energy if made to radically change direction such as moving from the 'bottom/windward side' at the luff or in an attempt to follow a large full draft shape will easily 'separate'. Light winds usually require FLAT sails, just as high winds require FLAT sails ... but for different reasons. Against all intuition, light wind sailing almost always requires the same (flattened) shape as 'high wind' sailing. FAST sailing requires FLATer shaped sails. POWER sailing (punching into and through waves, etc.) requires a more full draft shape. The 'norm' of using full draft sails in light winds (a powered-up shape) will usually lead to dismal performance ... because of the enhanced potential of flow separation. Sure, coming out of a tack you need to use 'first gear' or a power shape, but unless you shift to 'high gear' or use a speed shape your boat simply wont 'go'. Flat sails in high winds depower the shape, understandable for 'survival'; but, flat sails are FAST sails and flat sails will greatly enhance light wind sailing (once you get the boat moving). The use of a full set of tell tales and a good speedo will show and validate the effects. 1st gear: powered up shape ... deeper draft 3rd gear: speed shape .... less draft and flatter shape. You can always power-up ('dropping down a gear') with deeper draft to punch through waves or accelerate out of a tack, but should go back to flat once the boat gets back up to speed. Simply watch a full set to tell tales and speedo ... as they will tell you where/how/when/why you get optimum set/shape. Light winds usually need FLAT shape or the sail easily can get into a 'separation stall' - a stall that is totally invisible to the human eyeball - because the light winds dont have enough energy to stay 'attached'. Plus, If you use a full draft shape in light winds, you'll never get out of 'first gear'. A bendy mast with radical backstay tension adjustment is the 'key' for easy/rapid powering up and down and controlling the amount of draft ... too bad such is rarely found on a cruising boat. Racers are *constantly* changing the sail shape by halyard, outhaul, vang, mast bend, etc. tensions; cruisers usually just 'raise' the sails and hope for the best. ;-)
Oh Yes .... Intl. Moth Foilers !!!!!
I do so want one. The Australians have really pushed the design of this open class boat. The Ozies also have websites for one to build a DIY. There have been a LOT of changes over the past few years with the foiling version so its hard to 'keep up' with the constant and rapid improvements. The old moth class is now 75+ years old; but, the recent 'division' into foilers has really added interest. I want one, and I dont care how 'old' I am when I get mine built. As long as they stay an 'open development' boat class ... they will get faster, more unique, etc. In that video, youll note that the winds are only near ~12kts. !!!!!! http://www.moth-sailing.org/index.php
I do so want one. The Australians have really pushed the design of this open class boat. The Ozies also have websites for one to build a DIY. There have been a LOT of changes over the past few years with the foiling version so its hard to 'keep up' with the constant and rapid improvements. The old moth class is now 75+ years old; but, the recent 'division' into foilers has really added interest. I want one, and I dont care how 'old' I am when I get mine built. As long as they stay an 'open development' boat class ... they will get faster, more unique, etc. In that video, youll note that the winds are only near ~12kts. !!!!!! http://www.moth-sailing.org/index.php
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