I'd like to be able to get better sailing performance out of my Pilot House Motor Sailor. I'm going to put up a second head stay, parallel to my selftending, furling jib. I'll just use a halyard and hanks. Anyone got a suggestion, from experience, as to sail areas (125%, 150%, ??) that might increase the preformance to justify the investment. If anyone has hydraulic steering and needs suggestions for a rudder angle indicator. I took a piece of scrap aluminum and cut it to a radius just large enough to come through the teak rudder post cover in the cockpit. Attached it to the post, marked the rudder midship position, as well as max. and midpoints for travel in both directions. The only way I've found to tack successfully is to bring the boat about, is to set the rudder, and adjust direction and speed with the jib. It's almost impossible to sail with out knowing where the rudder is.
- Status
Cutters don't cut it
Split headsails seen in cutters aren't as efficient as a single headsail and single main seen in a sloop. The inner sail is set in the back wash of the outer sail and is slightly less efficient than the outer or leading one. The slot between the inner one and the mainsail is narrower so the backwash from the inner one affects the mainsail and reduces its efficiency as well. I don't think adding an inner stay will help performance and likely will reduce it while adding complexity to setting and trimming sails. The main reason for the cutter rig was that as headsails approached 400 square feet the conventional wisdom was that size was the maximum amount a healthy crew member could set and douse in most conditions. A single large genoa on a 40 footer was about as big as one person could handle. Roller furling has changed that. A removable inner stay still makes sense for offshore boats that need to set a small staysail for balance when the wind gets up and the sails are reefed down. I think the reason for the lack of performance is that the pilot house rig has the mainsail cut very high to clear the house top and the lack of a basic traveler to set and control mainsail shape. The PH version sets 457 square feet of sail to the regular OI33's 525 with the loss of sail area all in the mainsail. Dave Doolin 1969 M30 Angel's Wing
Split headsails seen in cutters aren't as efficient as a single headsail and single main seen in a sloop. The inner sail is set in the back wash of the outer sail and is slightly less efficient than the outer or leading one. The slot between the inner one and the mainsail is narrower so the backwash from the inner one affects the mainsail and reduces its efficiency as well. I don't think adding an inner stay will help performance and likely will reduce it while adding complexity to setting and trimming sails. The main reason for the cutter rig was that as headsails approached 400 square feet the conventional wisdom was that size was the maximum amount a healthy crew member could set and douse in most conditions. A single large genoa on a 40 footer was about as big as one person could handle. Roller furling has changed that. A removable inner stay still makes sense for offshore boats that need to set a small staysail for balance when the wind gets up and the sails are reefed down. I think the reason for the lack of performance is that the pilot house rig has the mainsail cut very high to clear the house top and the lack of a basic traveler to set and control mainsail shape. The PH version sets 457 square feet of sail to the regular OI33's 525 with the loss of sail area all in the mainsail. Dave Doolin 1969 M30 Angel's Wing
Wrong aerodynamic interpretation of a cutter rig
Simply most sloop sailors have no idea of how to set / trim a staysail under a jib/genoa. Although a 'finicky' sail to set a staysl definitely adds power especially when on a reach when it 'fills in the foretriangle'. Even the hi tech long distance racing folks are resurrecting staysails. For beating, a staysail properly trimmed and set, becomes an aerodynamic forward extension of the mainsail with the chief benefit of reduction of mast turbulence; hence, more a efficient mainsail that is able perform at a higher angle of attack - a more efficient mainsail makes the genoa more efficient. The 'set' is quite different aerodynamically than with other sails as in this mode the staysail is not 'visuallly drawing'. This set/trim is with a very flat staysl with a well 'rounded' entry or luff shape (accomplished with heavy halyard tension). Typical benefits will be an additional ~4-5 degrees of pointing ability and despite how large the overlapping genoa is. A staysail is difficult to trim/set; but, the application of tell-tales and 'gentry tufts' solves all the aerodynamic 'misperceptions'. With a boom a staysail becomes 'hands off' self tacking so the only 'difficulty' in tacking a genoa between the forestay and jibstay can be easily accomplished with a 'tricing line' - a light line mounted to a block then at the bow then run back to near the genoa clew ... that when pulled moves the genoa clew forward to sufficiently 'bunch' the genoa for easy passages between the fore/jib stays. Some of the Americas Cup sloops in the late 80s and early 90s used tricing lines to get their genoas quickly around exposed babystays. A boomed staysail is MORE aerodynamically efficient on a broad reach as the 'twist' can be precisely matched for the conditions; improper twist is the 'hallmark' of a masthead genoa on any point of sail below a high close reach. For tacking downwind a staysail can easily be flown on the lee (wing and wing) to add considerable and exposed (not shadowed) sail area while promoting even better flow over a genoa. So, sloop sailors who typically only race windward-leeward courses typically have little idea of how/when/why a cutter - designed with the intent for 'reaching'; hence the 'bias'. Most cruising and passagemaking is reaching and running ... and thats where the sloop is at a decided disadvantage and the cutter comes 'into its own'. No one can argue the versatility of choice of sail area exposure on a cutter, especially when the winds are 'up' and precise helm balance is desired. So if you are considering adding an inner forestay to fly a staysail, go for it. Even better add the largest staysl that you can. Do strongly consider a removable forestay with a 'levered toggle' attachment. Even better consider a 'solent rig'. .... for even more versatility add one of the newer roller furling set-ups for an asymmetrical spinnaker: http://www.rollgen.com/pdf/rollgen_e.pdf Hope this helps
Simply most sloop sailors have no idea of how to set / trim a staysail under a jib/genoa. Although a 'finicky' sail to set a staysl definitely adds power especially when on a reach when it 'fills in the foretriangle'. Even the hi tech long distance racing folks are resurrecting staysails. For beating, a staysail properly trimmed and set, becomes an aerodynamic forward extension of the mainsail with the chief benefit of reduction of mast turbulence; hence, more a efficient mainsail that is able perform at a higher angle of attack - a more efficient mainsail makes the genoa more efficient. The 'set' is quite different aerodynamically than with other sails as in this mode the staysail is not 'visuallly drawing'. This set/trim is with a very flat staysl with a well 'rounded' entry or luff shape (accomplished with heavy halyard tension). Typical benefits will be an additional ~4-5 degrees of pointing ability and despite how large the overlapping genoa is. A staysail is difficult to trim/set; but, the application of tell-tales and 'gentry tufts' solves all the aerodynamic 'misperceptions'. With a boom a staysail becomes 'hands off' self tacking so the only 'difficulty' in tacking a genoa between the forestay and jibstay can be easily accomplished with a 'tricing line' - a light line mounted to a block then at the bow then run back to near the genoa clew ... that when pulled moves the genoa clew forward to sufficiently 'bunch' the genoa for easy passages between the fore/jib stays. Some of the Americas Cup sloops in the late 80s and early 90s used tricing lines to get their genoas quickly around exposed babystays. A boomed staysail is MORE aerodynamically efficient on a broad reach as the 'twist' can be precisely matched for the conditions; improper twist is the 'hallmark' of a masthead genoa on any point of sail below a high close reach. For tacking downwind a staysail can easily be flown on the lee (wing and wing) to add considerable and exposed (not shadowed) sail area while promoting even better flow over a genoa. So, sloop sailors who typically only race windward-leeward courses typically have little idea of how/when/why a cutter - designed with the intent for 'reaching'; hence the 'bias'. Most cruising and passagemaking is reaching and running ... and thats where the sloop is at a decided disadvantage and the cutter comes 'into its own'. No one can argue the versatility of choice of sail area exposure on a cutter, especially when the winds are 'up' and precise helm balance is desired. So if you are considering adding an inner forestay to fly a staysail, go for it. Even better add the largest staysl that you can. Do strongly consider a removable forestay with a 'levered toggle' attachment. Even better consider a 'solent rig'. .... for even more versatility add one of the newer roller furling set-ups for an asymmetrical spinnaker: http://www.rollgen.com/pdf/rollgen_e.pdf Hope this helps
I'm nor so sure you can find the data Rich
While I can appreciate your esteem of the cutter rig, it's aerodynamic qualities aren't borne out in published studies of the past century. Rather than helping pointing, the scientific truth of the matter is that every sail in front of the mainsail reduces the angle the boat can sail to the true wind direction. When a foil creates lift it bends the wind slightly. I earlier called this backwash but it is more properly called downwash. The first sail in line bends the wind flowing over the one behind it as well as dirtying the flow a little. The jib therefore "heads" the cutter's staysail and the staysail heads the mainsail. Some argue that the main "lifts" the headsail but the end result is the same. The lift co-efficient of a jib/main sail plan is greater than the sum of both the sails measured separately. If a mizzen is behind the main it is headed by the mainsail. No one argues a ketch or yawl is more weatherly than a sloop. It has advantages in other areas already stated but out-pointing a sloop isn't one of them. I certainly agree a headsail increases the lift co-efficient of a mainsail alone by smoothing flow over the leeward surface and delaying breakdown of laminar flow as well as shifting the stagnation point around to the windward side of the main's leading edge but this is done quite handily with one headsail and with less weight and aero-dynamic drag in the bargain. Two successive headsails reduce the trim angle of the main more than one does. Research on this and related topics can be found in C.A. Marchaj's books Sail Performance and The Theory and Practice of Sailing as well as other texts. I concede that there are times that a cutter rig is desirable but for all around use the cutter rig has been left behind by handier rigs. For daysailing and short cruises it doesn't make sense to optimize an OI33 for reaching or heavy weather sailing at the expense of beating. For pete's sake - the pilot house version has a set of sliding glass doors for a companionway. Going offshore with those is questionable. At the end of the day you got to go home and we can't reach off or run foreever. In racing circles the cutter has been a non-starter for decades. While it is easy to say the rule book has handicapped double headsails out of existence this ignores the results of open developmental classes like Six Meters, International 14's, Australian Skiffs, etc.. In classes with no restrictions on sail plans or area the cutter is a non-starter. In the recent past windward-leeward courses have gained favor but most classes still race the triangle course of beat, reach, and run. Dave
While I can appreciate your esteem of the cutter rig, it's aerodynamic qualities aren't borne out in published studies of the past century. Rather than helping pointing, the scientific truth of the matter is that every sail in front of the mainsail reduces the angle the boat can sail to the true wind direction. When a foil creates lift it bends the wind slightly. I earlier called this backwash but it is more properly called downwash. The first sail in line bends the wind flowing over the one behind it as well as dirtying the flow a little. The jib therefore "heads" the cutter's staysail and the staysail heads the mainsail. Some argue that the main "lifts" the headsail but the end result is the same. The lift co-efficient of a jib/main sail plan is greater than the sum of both the sails measured separately. If a mizzen is behind the main it is headed by the mainsail. No one argues a ketch or yawl is more weatherly than a sloop. It has advantages in other areas already stated but out-pointing a sloop isn't one of them. I certainly agree a headsail increases the lift co-efficient of a mainsail alone by smoothing flow over the leeward surface and delaying breakdown of laminar flow as well as shifting the stagnation point around to the windward side of the main's leading edge but this is done quite handily with one headsail and with less weight and aero-dynamic drag in the bargain. Two successive headsails reduce the trim angle of the main more than one does. Research on this and related topics can be found in C.A. Marchaj's books Sail Performance and The Theory and Practice of Sailing as well as other texts. I concede that there are times that a cutter rig is desirable but for all around use the cutter rig has been left behind by handier rigs. For daysailing and short cruises it doesn't make sense to optimize an OI33 for reaching or heavy weather sailing at the expense of beating. For pete's sake - the pilot house version has a set of sliding glass doors for a companionway. Going offshore with those is questionable. At the end of the day you got to go home and we can't reach off or run foreever. In racing circles the cutter has been a non-starter for decades. While it is easy to say the rule book has handicapped double headsails out of existence this ignores the results of open developmental classes like Six Meters, International 14's, Australian Skiffs, etc.. In classes with no restrictions on sail plans or area the cutter is a non-starter. In the recent past windward-leeward courses have gained favor but most classes still race the triangle course of beat, reach, and run. Dave
- Status