Post by F-48 on Feb 28, 2004 20:20:06 GMT -5
This is an article of one of our members who has been in the multihull design and sailing forum for many years. Infact Jon and myself have crossed paths many times, I used to work for the other camp. The fact that this model sails with our Mini40 fleet gives you a very good indication that the theory works, no bits of lead flying about to keep the beast upright, four masts no less within the rules.
Reward - at last
Quatrefoil creator Jon Montgomery was presented with the AYRS John Hogg Prize for 2003 at the London Boat Show. The aim of this £1,000 annual international award - in memory of amateur yachting researcher john Hogg who died in 2000 - is to encourage and recognise important contributions to the understanding and development of sailing performance, safety and endurance. It is backed by the Amateur Yacht Research Society whose byword is 'Where the ideas are!' Some of the ideas can be slightly eccentric, but that's what is so delightful about the AYRS.
Jon Montgomery is not eccentric at all. He's been in and out of cat design and development since the pioneering days in the late 1950s, mainly as a sideline to professional working life and is probably best known as designer and developer of the Catapult which against the odds proved that a cat with inflatable hulls can look good, go fast, be fun to sail and be a practical boat to own. Jon turned his attention to Quatrefoil as a grand scale design solution for the first edition of The Race for unlimited yachts round the world. He's never come close to realising the 40m full size boat, but over the past few years has lavished a great deal of time and effort developing the concept. Of course the only radical boat that did get built for The Race was 'Team Phillips', a rather different design that came to a sticky end.
But there are some similarities to Quatrefoil , which is also designed to be handled at speed by a relatively small crew and has unstayed, rotating rigs, though four rather than the two on 'Team Phillips. Jon Montgomery has identified 'three key revolutionary attributes' of Quatrefoil . First is the idea of slewing hulls, which allows each hull to be angled 15 degrees forward or back. Jon believes 15 degrees could make a substantial difference to trim, with a hull movement of 6.88m creating a comparatively small 0.91m loss of overall beam. For reaching the leeward hull is angled forwards, getting weight well aft on the windward hull, which mimics the crew moving back on a beach cat to lift the leeward bow. For beating, the windward hull can be angled forward, helping the loaded leeward hull to punch through oncoming seas. This concept was also used by Simon Sanderson on his 60ft speedsailing machine once known as 'Bootiful' which sadly has never got near to its 50 knot target speed.
Jon also believes slewing hulls could open up the possibility of self-recovery. This has always been the bete noire of big multis, though monos fare even worse when they go upside-down. Harvey Bowden put a lot of effort into the concept on his 26ft Firebird 'Orion', but eventually came to the conclusion it was better to learn to sail the boat so it would never capsize. With bigger multis it has been unthinkable to right them without a long and damaging tow into shallow water. However, the bonus of an upside down multi is that it is as stable as the right way up. With such a well behaved platform to work from - albeit in a topsy-turvy world - the crew could winch the hulls close enough together to let buoyancy in the four wing masts float the cat onto its side. From there on, Jon thinks the combination of wave action and inflatable buoyancy could be used to flip the cat upright, though it sounds a long shot when dealing with a monster, 22 tonne boat.
Jon has been working on the slewing hull concept for the past 15 years, having tested two 600mm model cats (not unlike the Catapult) back in 1989. One had the leeward hull slewed forward, the other was conventional, and when both were sent on a reach across open water the slewed version invariably forged ahead with its leeward bow riding higher. Almost 10 years later Jon tried a full size version, having entered an 18ft Catapult for the 1998 Weymouth Speed Week that was specially engineered to provide up to 45 degrees of hull slewing. Reliability and speed were proven with a 17 knot run close to the all-time high for a Catapult, but the tests also showed that more than 20 degrees of slew could create unpleasant amounts of lee or weather helm with a normal single, central rig - one assumes you would need a canting rig to counteract this! The most recent tests have been undertaken with a Quatrefoil 1:25 scale model that sails with up to 15 degrees of slew, using lines from a radio controlled winch on the central nacelle to control the angles.
Jon's second key attribute is the method of supporting the quartet of free-standing rigs which are designed to produce a total sail-mast area of 514sq m (5,528sq ft). Apart from doubling up the rigs, there are some major differences from 'Team Phillips', which had considerable difficulties keeping the mast inside the boat - before the boat finally parted company from the masts. Quatrefoil chooses to side-step the considerable engineering challenge of securing a 20m tall, free standing wing mast in a 1.85m wide hull by mounting each mast on its respective cross beam end. This means the hulls are preserved for flotation and torsional strength, rather than as local high load bearing structures - which caused more problems for 'Team Philips.' Nor do the masts rotate on a fixed base at the foot. Instead, each mast has a short, fixed round mast or 'spigot' that fits up inside the hollow wing. This means the rotation point bearings are comparatively high in the mast and close to the centre of effort, taking load away from the base where the spigot is firmly secured with no requirement to rotate. Each boom has an interior bearing that slides over the mast spigot, allowing fore and aft balance between the foresail and mainsail loads with sails that furl inside the booms for reefing or stowing.
The third key attribute is Jon's design for 'knock-up, self jibing foils'. With this, he's tackling the problem of multihulls hitting UFOs (unidentified floating objects) at speed. It's a nightmare waiting to happen which at best necessitates retirement from a major event - as with 'ENZA' and 'PlayStation' on round the world trips - and at worst will flip a trimaran when control is lost due to hitting something with a rudder - as happened to 'Foncia' off the coast of Portugal. So Quatrefoil has externally mounted centreboards - rather like the leeboards on a Dutch barge - which will flip up on impact, with a 'self jibing control' through being able to introduce an angle of attack to each foil which aids lateral resistance. Flip-up rudders in each transom complete the package. They may be run of the mill on small cats, but are not common on big offshore multis due to engineering problems. Quatrefoil attempts to get over this with a system that allows the helmsman to continue steering with one rudder knocked upright, although this can only be a temporary measure if it's in the leeward hull.
Unfortunately, the provided photo of this 4 masted multihull was of poor quality, and I was not able to post it here. - ADMIN
Reward - at last
Quatrefoil creator Jon Montgomery was presented with the AYRS John Hogg Prize for 2003 at the London Boat Show. The aim of this £1,000 annual international award - in memory of amateur yachting researcher john Hogg who died in 2000 - is to encourage and recognise important contributions to the understanding and development of sailing performance, safety and endurance. It is backed by the Amateur Yacht Research Society whose byword is 'Where the ideas are!' Some of the ideas can be slightly eccentric, but that's what is so delightful about the AYRS.
Jon Montgomery is not eccentric at all. He's been in and out of cat design and development since the pioneering days in the late 1950s, mainly as a sideline to professional working life and is probably best known as designer and developer of the Catapult which against the odds proved that a cat with inflatable hulls can look good, go fast, be fun to sail and be a practical boat to own. Jon turned his attention to Quatrefoil as a grand scale design solution for the first edition of The Race for unlimited yachts round the world. He's never come close to realising the 40m full size boat, but over the past few years has lavished a great deal of time and effort developing the concept. Of course the only radical boat that did get built for The Race was 'Team Phillips', a rather different design that came to a sticky end.
But there are some similarities to Quatrefoil , which is also designed to be handled at speed by a relatively small crew and has unstayed, rotating rigs, though four rather than the two on 'Team Phillips. Jon Montgomery has identified 'three key revolutionary attributes' of Quatrefoil . First is the idea of slewing hulls, which allows each hull to be angled 15 degrees forward or back. Jon believes 15 degrees could make a substantial difference to trim, with a hull movement of 6.88m creating a comparatively small 0.91m loss of overall beam. For reaching the leeward hull is angled forwards, getting weight well aft on the windward hull, which mimics the crew moving back on a beach cat to lift the leeward bow. For beating, the windward hull can be angled forward, helping the loaded leeward hull to punch through oncoming seas. This concept was also used by Simon Sanderson on his 60ft speedsailing machine once known as 'Bootiful' which sadly has never got near to its 50 knot target speed.
Jon also believes slewing hulls could open up the possibility of self-recovery. This has always been the bete noire of big multis, though monos fare even worse when they go upside-down. Harvey Bowden put a lot of effort into the concept on his 26ft Firebird 'Orion', but eventually came to the conclusion it was better to learn to sail the boat so it would never capsize. With bigger multis it has been unthinkable to right them without a long and damaging tow into shallow water. However, the bonus of an upside down multi is that it is as stable as the right way up. With such a well behaved platform to work from - albeit in a topsy-turvy world - the crew could winch the hulls close enough together to let buoyancy in the four wing masts float the cat onto its side. From there on, Jon thinks the combination of wave action and inflatable buoyancy could be used to flip the cat upright, though it sounds a long shot when dealing with a monster, 22 tonne boat.
Jon has been working on the slewing hull concept for the past 15 years, having tested two 600mm model cats (not unlike the Catapult) back in 1989. One had the leeward hull slewed forward, the other was conventional, and when both were sent on a reach across open water the slewed version invariably forged ahead with its leeward bow riding higher. Almost 10 years later Jon tried a full size version, having entered an 18ft Catapult for the 1998 Weymouth Speed Week that was specially engineered to provide up to 45 degrees of hull slewing. Reliability and speed were proven with a 17 knot run close to the all-time high for a Catapult, but the tests also showed that more than 20 degrees of slew could create unpleasant amounts of lee or weather helm with a normal single, central rig - one assumes you would need a canting rig to counteract this! The most recent tests have been undertaken with a Quatrefoil 1:25 scale model that sails with up to 15 degrees of slew, using lines from a radio controlled winch on the central nacelle to control the angles.
Jon's second key attribute is the method of supporting the quartet of free-standing rigs which are designed to produce a total sail-mast area of 514sq m (5,528sq ft). Apart from doubling up the rigs, there are some major differences from 'Team Phillips', which had considerable difficulties keeping the mast inside the boat - before the boat finally parted company from the masts. Quatrefoil chooses to side-step the considerable engineering challenge of securing a 20m tall, free standing wing mast in a 1.85m wide hull by mounting each mast on its respective cross beam end. This means the hulls are preserved for flotation and torsional strength, rather than as local high load bearing structures - which caused more problems for 'Team Philips.' Nor do the masts rotate on a fixed base at the foot. Instead, each mast has a short, fixed round mast or 'spigot' that fits up inside the hollow wing. This means the rotation point bearings are comparatively high in the mast and close to the centre of effort, taking load away from the base where the spigot is firmly secured with no requirement to rotate. Each boom has an interior bearing that slides over the mast spigot, allowing fore and aft balance between the foresail and mainsail loads with sails that furl inside the booms for reefing or stowing.
The third key attribute is Jon's design for 'knock-up, self jibing foils'. With this, he's tackling the problem of multihulls hitting UFOs (unidentified floating objects) at speed. It's a nightmare waiting to happen which at best necessitates retirement from a major event - as with 'ENZA' and 'PlayStation' on round the world trips - and at worst will flip a trimaran when control is lost due to hitting something with a rudder - as happened to 'Foncia' off the coast of Portugal. So Quatrefoil has externally mounted centreboards - rather like the leeboards on a Dutch barge - which will flip up on impact, with a 'self jibing control' through being able to introduce an angle of attack to each foil which aids lateral resistance. Flip-up rudders in each transom complete the package. They may be run of the mill on small cats, but are not common on big offshore multis due to engineering problems. Quatrefoil attempts to get over this with a system that allows the helmsman to continue steering with one rudder knocked upright, although this can only be a temporary measure if it's in the leeward hull.
Unfortunately, the provided photo of this 4 masted multihull was of poor quality, and I was not able to post it here. - ADMIN