Very interesting question. Close hauled in very light air I'd choose the bigger sail. The extra overlap will provide better airflow through the slot and keep the main from stalling. With the main working better the airflow on the outside of the genoa will speed up and the boat will go faster.
Big Jib or Small Jib
- Thread starter Don Guillette
- Start date
- Status
It was....on our 1st boat. For the 1st 3 weeks we owned it, I couldn't figure out why we couln't sail upwind worth a c***p...until I did some reading and discovered that you had to let the topping lift loose. Sailed like a different boat after that
So back to the original question. If (and that's a big if) that I was on the right track that the larger jib might be backwinding the main, causing trim issues with it, you could let out a little on the jib to increase the slot and stop the backwinding. But then the jib might not be properly trimmed for close hauling. So, in this case, a properly trimmed smaller jib coupled with a non-backwinded properly trimmed main might be fastest.
Scott
Scott
Last edited:
From everything I've read, and starting to practice: masthead rigs use the jib as the driving force, while the main is used for balance. A C30 in 5-6kts steady wind whould be able to easily handle any of your listed sails: 135, 150 etc. for upwind duty, tighten your forestay with the backstay adjuster. Check your telltales (outside flying straight back, inside just short of fluttering up) good tension should show all three flying simlar. don you also mentioned eas of handling. there are a couple of different tricks you can use to make hauling in the sail easier: slow the turn to give you time to tighten the sheet prior to it fully loading up. Our two-speed winches do a nice job of finishing the trimming with little force.
Mainsail trim: I again refer to the telltales, twisting the sail enough for all to flow back straight.
Mainsail trim: I again refer to the telltales, twisting the sail enough for all to flow back straight.
Here's maybe the final 'tease' ........
What do the high end boats that race windward (closehauled) / leeward (spinnaker/Gennaker) courses, such as the maxi boats and Americas Cup boats (before the advent of 'foiling' catamarans) look like?
What do the high end boats that race windward (closehauled) / leeward (spinnaker/Gennaker) courses, such as the maxi boats and Americas Cup boats (before the advent of 'foiling' catamarans) look like?
Since I know very little yet what works and what don't I will say what I would do and why. I would use my 130 and do what ever it takes to get it trimmed in as far as possible. Because this reduces the slot and the the 130 captures more wind causing higher airflow across the main sail causing more power and more speed.
I go along with the smaller sail. Having a 150 for my primary genoa, I have seen where it is very difficult to keep the air flow attached to the sail on both sides when the wind speed is as low as 5 knots. I've seen a tendency for the leach to hook, which further disrupts air flow, disturbs the air flow thru the slot and messes up the main and slows down the boat. I'd sure like to have a 135 because I think it would be better for getting the sail to look more like a blade. As the breeze drops, its better to have a flatter shape for both sails to keep the air flow attached and reduce turbulence.
Headsail Heresy, Perhaps...
Our boat has a "balanced" rig, between main and jib. Perhaps not too different from the traditional Cat 30 rig. Maybe.
So, after 15 years of living with a 135 genoa, last summer we decided to go with a new 95% jib. Still roller furling, but with Vertical Battens. This gives an upper leach equal to about a regular 120%, to my untrained eye. Maybe.
Results are astounding. In anything over about 8 knots we go to weather Very Well, and can still point like a Meter Boat with one reef in the main at 18 kts true. Typical speed to weather is over 7 kts.
Of course tacking the boat is now easy. Very easy.
We have lost some speed in light air, but the trade off seems well worth it. And since our slowest direction now is DW or up to a close reach in light air, we are saving for a new A-sail with top-down furling. And that... will become our total inventory. The old tri-radial spinnaker will get retired -- great sail but it takes a while to set up and another while to put away.
Many 'right' answers, but at least this may give you something more to consider.
I will attach pics of the boat with the 135 and with the new 95; not on the same point of sail, so the comparison is not as easy to see as it should be.
Fair winds,
Loren
Our boat has a "balanced" rig, between main and jib. Perhaps not too different from the traditional Cat 30 rig. Maybe.
So, after 15 years of living with a 135 genoa, last summer we decided to go with a new 95% jib. Still roller furling, but with Vertical Battens. This gives an upper leach equal to about a regular 120%, to my untrained eye. Maybe.
Results are astounding. In anything over about 8 knots we go to weather Very Well, and can still point like a Meter Boat with one reef in the main at 18 kts true. Typical speed to weather is over 7 kts.
Of course tacking the boat is now easy. Very easy.
We have lost some speed in light air, but the trade off seems well worth it. And since our slowest direction now is DW or up to a close reach in light air, we are saving for a new A-sail with top-down furling. And that... will become our total inventory. The old tri-radial spinnaker will get retired -- great sail but it takes a while to set up and another while to put away.
Many 'right' answers, but at least this may give you something more to consider.
I will attach pics of the boat with the 135 and with the new 95; not on the same point of sail, so the comparison is not as easy to see as it should be.
Fair winds,
Loren
Attachments
And the winner is: 2 of you !!!! but each of you have to send Don's Guide to the next in the list starting with and in order ...
1a. SeSmith ... bigger sail = bigger 'backwind', etc. in post #13, etc.
1b. Benny17441 ... better pointing ability with a smaller jib
Honorable mention: all you folks who participated!!!!!
Other Honorable mention:
1c. ScottT-bird ... FLOW ATTACHMENT better and easier to control with smaller sails !!!!!!! … even that he showed up late in the game.
Simple answers:
For light wind sailing, the smaller the LP and the flatter the draft the better the pointing ability.
Here’s the explanation.
Consider that air flowing across sails imparts or transfers energy to the sail and that energy can only be transferred if the air flow stays attached to the surface of the sail. In light and super light wind conditions the wind doesn’t have all that much energy, including energy to keep the flow attached to a sail … and the longer air has to travel while giving up its energy to the sail, the less energy it will have in the aft sections to stay attached … and not become a ‘separation stall’. Successful light wind sailing ‘starts’ with the prevention of ‘separation stalls’.
I don’t want to bore you with ‘aerodynamics’ but for wings and foils and sails, there is one very important fluid dynamics ‘law’ – the air/fluid flow leaving AT the trailing edge MUST be at equal velocity on both sides of the trailing edge, OR little to NO lift is created in the sail, etc. (called Kutta Condition) and that’s why we put lots of tell tales on the leeches of sails!!!!!!
So, If a BIG sail saps all the energy from the wind BEFORE it gets to the trailing edge and/or which causes a ‘separation’ of the flow … what is the energy imparted to the sail? Answer – nil to nada, the sail has a separation stall going on; and, if ‘kutta’ is not met – NO lift.
Lower air speeds causes a higher frequency of ‘separation stalls’ the longer distance the air has to travel along the lee side of a sail !!!!!! Therefore, to insure against such separation stalls: In lower energy wind, the choice towards the smaller the cord length (LP) sail is to better insure attached flow.
Also too, that’s why sails used in very light winds should be somewhat ‘flattish’ and with greatly reduced amount of draft (BIG outhaul tension). Low energy wind will not so easily ‘turn corners’ (such as too much draft in the sail) which increases the propensity for a ‘separation stall’.
In all cases set the amount of draft / outhaul tension by watching the speedo – the higher the speedo, the higher the ‘apparent wind’.
Also, and as noted by some posters, a smaller LP jib will usually promote better pointing (VMG) ….
Reason: with a BIG overlapping jib the flow velocity from the jib leech ‘may’ be too far aft onto or near the mainsail, as most all the ‘forward drive’ in a sail occurs mostly at ‘just aft of the luff’, tapering off in ‘driving force’ to where draft is at its maximum, and very little ‘forward’ after the point of maximum draft. When the LP of the jib is too large for a match with the mainsail, the jib will not correctly 'bootstrap' or 'dump its velocity' to the mainsail. With less mainsail efficiency due to a too large LP jib/genoa, there will be less ‘upwash’ for the jib to operate in with the result that the boat simply wont be able to point as well and will have to bear off a bit to get equal speed.
With sail interaction, one of the major functions of the mainsail is to create better ‘upwash’ for the jib to operate - 'upwash' is those flow stream lines well out in front of the oncoming boat/sails that are 'bending' and heading toward the leeside of the jib's leading edge.
Sail ‘interaction’ happens this way: the mainsail makes the jib more efficient and an efficient jib makes the mainsail more efficient.
FWIW – Mast headed boats were designed to use BIG jibs because you didn’t need to raise a troublesome spinnaker when going down or reaching/tacking downwind. Since there are usually no ‘reaching legs’ on most race courses nowadays, what usually wins is a fractional rig with a 100-120% jib, using an asymmetrical when going down wind – such a boat now has two available optimized points of sail: beating and reaching down.
Epilogue.
The ‘real’ answer for yourself and if you have ‘several’ sails is: take them out and compare the differences on YOUR BOAT and in all possible conditions, and write the stuff down … because your boat is different than everybody elses boat, even between two boats from the same manufacturer. Don’t ‘believe’ until you verify, in this way you may be quite surprised.
If racing is your game or future game, If you don’t have the developed reference data of many many 'trials' for your boat in various conditions, you better have a damn good memory, a memory better than most folks who cant remember what they had for dinner last Tuesday.
Postscripts:
"Fast Olsens" testimony came in a bit too late and after I did my write up. But his testimony will support the conclusions already given.
I really like Weinie’s sail shape in post #29
‘Protests’ about the selected winners, etc. can be filed in the race committee room until noontime, yesterday. ;-)
Hope you all enjoyed all the discussion.
1a. SeSmith ... bigger sail = bigger 'backwind', etc. in post #13, etc.
1b. Benny17441 ... better pointing ability with a smaller jib
Honorable mention: all you folks who participated!!!!!
Other Honorable mention:
1c. ScottT-bird ... FLOW ATTACHMENT better and easier to control with smaller sails !!!!!!! … even that he showed up late in the game.
Simple answers:
For light wind sailing, the smaller the LP and the flatter the draft the better the pointing ability.
Here’s the explanation.
Consider that air flowing across sails imparts or transfers energy to the sail and that energy can only be transferred if the air flow stays attached to the surface of the sail. In light and super light wind conditions the wind doesn’t have all that much energy, including energy to keep the flow attached to a sail … and the longer air has to travel while giving up its energy to the sail, the less energy it will have in the aft sections to stay attached … and not become a ‘separation stall’. Successful light wind sailing ‘starts’ with the prevention of ‘separation stalls’.
I don’t want to bore you with ‘aerodynamics’ but for wings and foils and sails, there is one very important fluid dynamics ‘law’ – the air/fluid flow leaving AT the trailing edge MUST be at equal velocity on both sides of the trailing edge, OR little to NO lift is created in the sail, etc. (called Kutta Condition) and that’s why we put lots of tell tales on the leeches of sails!!!!!!
So, If a BIG sail saps all the energy from the wind BEFORE it gets to the trailing edge and/or which causes a ‘separation’ of the flow … what is the energy imparted to the sail? Answer – nil to nada, the sail has a separation stall going on; and, if ‘kutta’ is not met – NO lift.
Lower air speeds causes a higher frequency of ‘separation stalls’ the longer distance the air has to travel along the lee side of a sail !!!!!! Therefore, to insure against such separation stalls: In lower energy wind, the choice towards the smaller the cord length (LP) sail is to better insure attached flow.
Also too, that’s why sails used in very light winds should be somewhat ‘flattish’ and with greatly reduced amount of draft (BIG outhaul tension). Low energy wind will not so easily ‘turn corners’ (such as too much draft in the sail) which increases the propensity for a ‘separation stall’.
In all cases set the amount of draft / outhaul tension by watching the speedo – the higher the speedo, the higher the ‘apparent wind’.
Also, and as noted by some posters, a smaller LP jib will usually promote better pointing (VMG) ….
Reason: with a BIG overlapping jib the flow velocity from the jib leech ‘may’ be too far aft onto or near the mainsail, as most all the ‘forward drive’ in a sail occurs mostly at ‘just aft of the luff’, tapering off in ‘driving force’ to where draft is at its maximum, and very little ‘forward’ after the point of maximum draft. When the LP of the jib is too large for a match with the mainsail, the jib will not correctly 'bootstrap' or 'dump its velocity' to the mainsail. With less mainsail efficiency due to a too large LP jib/genoa, there will be less ‘upwash’ for the jib to operate in with the result that the boat simply wont be able to point as well and will have to bear off a bit to get equal speed.
With sail interaction, one of the major functions of the mainsail is to create better ‘upwash’ for the jib to operate - 'upwash' is those flow stream lines well out in front of the oncoming boat/sails that are 'bending' and heading toward the leeside of the jib's leading edge.
Sail ‘interaction’ happens this way: the mainsail makes the jib more efficient and an efficient jib makes the mainsail more efficient.
FWIW – Mast headed boats were designed to use BIG jibs because you didn’t need to raise a troublesome spinnaker when going down or reaching/tacking downwind. Since there are usually no ‘reaching legs’ on most race courses nowadays, what usually wins is a fractional rig with a 100-120% jib, using an asymmetrical when going down wind – such a boat now has two available optimized points of sail: beating and reaching down.
Epilogue.
The ‘real’ answer for yourself and if you have ‘several’ sails is: take them out and compare the differences on YOUR BOAT and in all possible conditions, and write the stuff down … because your boat is different than everybody elses boat, even between two boats from the same manufacturer. Don’t ‘believe’ until you verify, in this way you may be quite surprised.
If racing is your game or future game, If you don’t have the developed reference data of many many 'trials' for your boat in various conditions, you better have a damn good memory, a memory better than most folks who cant remember what they had for dinner last Tuesday.
Postscripts:
"Fast Olsens" testimony came in a bit too late and after I did my write up. But his testimony will support the conclusions already given.
I really like Weinie’s sail shape in post #29
‘Protests’ about the selected winners, etc. can be filed in the race committee room until noontime, yesterday. ;-)
Hope you all enjoyed all the discussion.
I had no idea but thought that due to the need to flatten in light winds that less 'flat' sail material would be better. However at some point too small would create diminishing returns, hence my dilemma, I therefore concluded that this could not be determined as a thought experiment only. Taking it to extremes, a trysail would be a poor choice in 3kts, but then I can see how a 300 (or something equally ridiculous) would also fail, so while there is an optimal size in there, between a 150 and a 135 trail and error is the only way to figure it out for sure. Besides, I already have the sail chart. (But I did learn something...thanks!)
(But I did learn something...thanks!)
Completely contrary to the (correct) logic RichH explained, a huge "equally ridiculous" sail does in fact work very well in light air (see the picture in my previous post on this thread, despite the fact the sail looks like it's not full). It is almost like an asym for going upwind (but pointing suffers, VMG doesn't usually suffer much since you're really moving along at a much faster speed). Why it works however is quite different than the physics behind the way RichH just described.
I can go out in 3kts of wind with my drifter in flat seas and move along at usually about 3kts of boat speed (upwind). One particular night a few years ago (when I still had my old blown main) I was out with a friend and another friend was out on his Catalina 25, which had new sails. These two boats are on paper very similar specs and rated, although I am rated, and normally perform a touch faster. However we quite literally sailed in circles around his boat for half an hour plus. there wasn't enough air to hardly drive his rig (he was doing about 1kt), yet my 220% drifter would move me along at 2-3kts.
I believe the way this sail works so well is the fact the drifter overlaps the main so that about 80% of the main has the drifter leward of it, creating a massive slot compared to that of a standard 135 or 150 genoa. I have taken my hand held anemometer and measured apparent wind at the bow of 6kts, and at the same time apparent wind in the slot between the drifter and main was 8kts (with my boat speed at 5.5+), and with 7kts of apparent wind I have seen slot speeds in excess of 9.5kts, and boat speed in excess of 7kts.
Since the drifter channels the air over nearly the entire back of the main, it will effectively power the main with good laminar flow coupled with a significant increase in apparent wind, even if the drifter itself is badly stalled without much attached flow. Therefore most of my power in those conditions is actually from the main, and the drifter's primary role is being that of a giant wind scoop to run the air over the back of the main and increase apparent wind.
It's the closest thing I've ever seen to truly making your own wind
Shipmates: Congrats to the winners!! Send me your street address at yankee3223@juno.com.
As a point of info -- I have only ONE sail and it's a 135.
The trick to this exercise was the WHY. Anyone could guess at the answer and a lot of newbies (intermediates also) do guess anytime they make a sail trim adjustment for their main and jib. Once a mate figures out the WHY of sail trim they're well on the way to becoming an excellent sail trimmer.
Thanks to all that participated and thanks to RichH for the time he spent plus the great hints he provided. Now that you know how the game works - you have to explain your choice (WHY) to win and of course your explanation must be correct.
We'll do this again when an appropriate topic comes up. I'll see if I can get Phil/Bly to spring for a SAIL TRIM USERS GUIDE the next time -- they're much richer than I am!!
As a point of info -- I have only ONE sail and it's a 135.
The trick to this exercise was the WHY. Anyone could guess at the answer and a lot of newbies (intermediates also) do guess anytime they make a sail trim adjustment for their main and jib. Once a mate figures out the WHY of sail trim they're well on the way to becoming an excellent sail trimmer.
Thanks to all that participated and thanks to RichH for the time he spent plus the great hints he provided. Now that you know how the game works - you have to explain your choice (WHY) to win and of course your explanation must be correct.
We'll do this again when an appropriate topic comes up. I'll see if I can get Phil/Bly to spring for a SAIL TRIM USERS GUIDE the next time -- they're much richer than I am!!
FourPoints -
Think carefully about whats happening in 'the slot'.
Is the wind 'actually' speeding up in the slot? and if it did, would not then the air be faster on the windward side of the jib than on the lee side of the jib and in doing so radically reduce the effectiveness of the jib?
Of course, if the "slot distance" is greatly reduced there may be faster flow through 'some' sections of it; but, that faster flow will vastly reduce the efficiency of the jib (faster flow on the jibs 'windward' side???) which in turn would then reduces the efficiency of the mainsail? .... and the reduction in the ability to point as you described !!!!!
There are some 'landmark' aerodynamic papers that explain 'slots and slats' (aircraft) but are quite 'technical' that show the key element of air flow in these is to SLOW the air through these regions which in turn increases flow to the adjacent regions .... and is quite the opposite of 'intuition' -
Suggest that if interested in a better understanding of lift and 'the slot effect':
First- http://www.arvelgentry.com/techs/origins_of_lift.pdf
Then, http://www.arvelgentry.com/magaz/Another_Look_at_Slot_Effect.pdf -
and Then, http://www.arvelgentry.com/magaz/More_on_the_Slot_Effect.pdf
In summary from these articles you will find that the 'slot' actually slows down the air flow in it due to the 'sums' of the circulation flow around both sails, and thus (importantly) causes the mainsail to cause 'more air' to be shifted onto the lee side of the jib, causing a larger 'upwash' to the jib to operate in - hence better pointing ability overall.
If you have a hand held anemometer (on a stick), suggest that you set up the sail's trim and shaping to 'perfect', then set the 'best' slot distance by barberhauling while watching the speedo and VMG and once youve attained close to perfection ..... measure with the anemometer close to the surfaces of the sail the air stream velocity over various locations windward / leeward / at the luff / at the trailing edges, including as high as you can reach, etc. If youre close to 'correct' in trim and shape -- you will experience/measure that the air flow in the 'slot' is vastly reduced !!!!!, not 'sped up'. Keen racers SEE this 'slowing down' in the slot quite frequently -- its that 'happy bubble' that develops in the mainsails's luff section, when the boat is at total 'optimum'.
Also interesting will be that if you subtract the FORWARD speed of the boat from all your wind speed readings/observations, dont be surprised if you find a LOT of the air, especially on the windward side of the sails to appear to be apparently moving FORWARD (showing that 'circulation flow')!!!!!!!
Think carefully about whats happening in 'the slot'.
Is the wind 'actually' speeding up in the slot? and if it did, would not then the air be faster on the windward side of the jib than on the lee side of the jib and in doing so radically reduce the effectiveness of the jib?
Of course, if the "slot distance" is greatly reduced there may be faster flow through 'some' sections of it; but, that faster flow will vastly reduce the efficiency of the jib (faster flow on the jibs 'windward' side???) which in turn would then reduces the efficiency of the mainsail? .... and the reduction in the ability to point as you described !!!!!
There are some 'landmark' aerodynamic papers that explain 'slots and slats' (aircraft) but are quite 'technical' that show the key element of air flow in these is to SLOW the air through these regions which in turn increases flow to the adjacent regions .... and is quite the opposite of 'intuition' -
Suggest that if interested in a better understanding of lift and 'the slot effect':
First- http://www.arvelgentry.com/techs/origins_of_lift.pdf
Then, http://www.arvelgentry.com/magaz/Another_Look_at_Slot_Effect.pdf -
and Then, http://www.arvelgentry.com/magaz/More_on_the_Slot_Effect.pdf
In summary from these articles you will find that the 'slot' actually slows down the air flow in it due to the 'sums' of the circulation flow around both sails, and thus (importantly) causes the mainsail to cause 'more air' to be shifted onto the lee side of the jib, causing a larger 'upwash' to the jib to operate in - hence better pointing ability overall.
If you have a hand held anemometer (on a stick), suggest that you set up the sail's trim and shaping to 'perfect', then set the 'best' slot distance by barberhauling while watching the speedo and VMG and once youve attained close to perfection ..... measure with the anemometer close to the surfaces of the sail the air stream velocity over various locations windward / leeward / at the luff / at the trailing edges, including as high as you can reach, etc. If youre close to 'correct' in trim and shape -- you will experience/measure that the air flow in the 'slot' is vastly reduced !!!!!, not 'sped up'. Keen racers SEE this 'slowing down' in the slot quite frequently -- its that 'happy bubble' that develops in the mainsails's luff section, when the boat is at total 'optimum'.
Also interesting will be that if you subtract the FORWARD speed of the boat from all your wind speed readings/observations, dont be surprised if you find a LOT of the air, especially on the windward side of the sails to appear to be apparently moving FORWARD (showing that 'circulation flow')!!!!!!!
Last edited:
I wanted to add the following to my 'summary' post that helps validate the 'trend' to smaller and smaller jibs over the years:
Back when 'most' of our current boats were designed, the 'vogue' then was for Mastheaded rigs with giant headsails and relatively smaller mainsails. The thinking probably was that the BIG jibs would be beneficial for downwind sailing, especially dead downwind when simply your boat speed depended solely on the amount of square feet of sail put up. This is equivalent to the thinking of the day when racers used many many specialty downwind sails in addidition to a symmetrical spinnaker ... tallboys and 'bloopers' that flew on the opposite side of the spinnker, spinnaker staysails, etc. that were raised 'under' the spinnaker and between it and the mainsail, 'drifters', etc. etc. .... quite grotesque and created the need for VAST and expensive sail inventory. All that was fine, as everyone simply 'followed the leader' around the (quite boring) race course.
Then something quite startling happened, probably introduced from the iceboat sailors who were experiencing that if the AWA could be increased by sailing off at an angle or 'reaching and tacking (gybing)' downwind to keep the apparent wind (and VMG) at a much higher value, such sluggish 'dead down wind' sailors would be entirely left in the dust behind those who were tacking downwind (keeping their apparent wind as high as possible).
This then probably caused another good look at fractional rig boats with smallish jibs and BIG mainsail (which since ancient times were deemed as 'pointing/upwind machines') and simultaneously these 'frac boats' also started flying asymmetrical spins that optimized at the max. point of when on a (135°-145°) broad reach.
The high-end folks immediately changed over ... the Americas Cup (after the 1950s), and the 'maxi's', etc. all changed to fractional or near fractional rigs and even if a big overlapping headsail was used you hardy ever saw anything larger than a 120 and this 'progress or evolution' continued to the extreme configurations you see in todays AC boats (catamarans), etc. with quite smallish jibs with LARGE and very tall 'square top' mainsails, etc.
This apparent shift in configuration over the past 30-40 years to BIG mainsails (or wings') and smaller jibs should be a signal to everyone (to those who sail at angles other than dead downwind) that there is a very strong reason for the smaller jibs, even if you are sailing a 'mast headed' boat: .... the better ability to 'point' plus the ability to help 'make' your own apparent wind ... and the 'bigger and taller' the mainsail, the bigger the 'upwash' is way out in front of the boat, for the jib to operate in !!!!!
;-)
Back when 'most' of our current boats were designed, the 'vogue' then was for Mastheaded rigs with giant headsails and relatively smaller mainsails. The thinking probably was that the BIG jibs would be beneficial for downwind sailing, especially dead downwind when simply your boat speed depended solely on the amount of square feet of sail put up. This is equivalent to the thinking of the day when racers used many many specialty downwind sails in addidition to a symmetrical spinnaker ... tallboys and 'bloopers' that flew on the opposite side of the spinnker, spinnaker staysails, etc. that were raised 'under' the spinnaker and between it and the mainsail, 'drifters', etc. etc. .... quite grotesque and created the need for VAST and expensive sail inventory. All that was fine, as everyone simply 'followed the leader' around the (quite boring) race course.
Then something quite startling happened, probably introduced from the iceboat sailors who were experiencing that if the AWA could be increased by sailing off at an angle or 'reaching and tacking (gybing)' downwind to keep the apparent wind (and VMG) at a much higher value, such sluggish 'dead down wind' sailors would be entirely left in the dust behind those who were tacking downwind (keeping their apparent wind as high as possible).
This then probably caused another good look at fractional rig boats with smallish jibs and BIG mainsail (which since ancient times were deemed as 'pointing/upwind machines') and simultaneously these 'frac boats' also started flying asymmetrical spins that optimized at the max. point of when on a (135°-145°) broad reach.
The high-end folks immediately changed over ... the Americas Cup (after the 1950s), and the 'maxi's', etc. all changed to fractional or near fractional rigs and even if a big overlapping headsail was used you hardy ever saw anything larger than a 120 and this 'progress or evolution' continued to the extreme configurations you see in todays AC boats (catamarans), etc. with quite smallish jibs with LARGE and very tall 'square top' mainsails, etc.
This apparent shift in configuration over the past 30-40 years to BIG mainsails (or wings') and smaller jibs should be a signal to everyone (to those who sail at angles other than dead downwind) that there is a very strong reason for the smaller jibs, even if you are sailing a 'mast headed' boat: .... the better ability to 'point' plus the ability to help 'make' your own apparent wind ... and the 'bigger and taller' the mainsail, the bigger the 'upwash' is way out in front of the boat, for the jib to operate in !!!!!
;-)
Wow!!! Interesting, I do have a mast head rig with large overlapping genoa 155%. That explains a lot for my performance in light winds. Thank you! So, would this also hold true for sailing off the wind? Say beam or broad reach? Smaller sail or larger?
Rich, that historical perspective is quite illuminating. It gives credence to those of us who have been discussing this for many, many years, and concluding that 155% jibs "appear to be" way oversized for "normal" cruising and beer can or PHRF racing. Those who have these big jibs tend to be in the camp that believes that bigger is better in light air, which this topic really discussed in depth and knowledge.
A 130 or 135 may be the largest sail anybody needs (masthead rig skippers alone, Hunter rigs are a different animal). As Fast Olsen mentioned, he has had great success with an even smaller headsail for pointing AND light air performance.
If going from a 155 to a smaller headsail, the complementary sail suit tends to go: smaller headsail, and an asymetric for long distance downwind work.
If one chooses to belay the AS, then a whisker pole is indicated for downwind work.
Or, just sit back, leave your mainsail covered (or furled, these days!) and let your jib pull you along.
Great discussion, thanks Don and Rich.
A 130 or 135 may be the largest sail anybody needs (masthead rig skippers alone, Hunter rigs are a different animal). As Fast Olsen mentioned, he has had great success with an even smaller headsail for pointing AND light air performance.
If going from a 155 to a smaller headsail, the complementary sail suit tends to go: smaller headsail, and an asymetric for long distance downwind work.
If one chooses to belay the AS, then a whisker pole is indicated for downwind work.
Or, just sit back, leave your mainsail covered (or furled, these days!
) and let your jib pull you along. Great discussion, thanks Don and Rich.
- Status