I received the routine email from MacGregorOwners.com The "Ask the Expert" question was if loose footed main sails were better than other sails. The answer from Mark Ploch was yes, for a number of reasons. This is a topic I have been interested in, but have found little information on it. Can you provide references or more information about loose footed mainsails? I am wondering if a vang would be useful on such a sail and what is the best way to attach the sail to the boom. I bought a 1995 Mac 19 last summer and it has a loose footed main. Thanks!
loose footed sails
- Thread starter Jayne
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loosely
A loose-footed main is usually found on in-mast furling rigs. They are typically zero-roach sails to accomadate the furling and as such they lose a percentage of their area, with a negative impact on performance, but they are easy to handle. In moderate/heavy air use a vang and the outhaul to tighten them down, but in light air, slack the outhaul slightly to allow a fuller shape.
A loose-footed main is usually found on in-mast furling rigs. They are typically zero-roach sails to accomadate the furling and as such they lose a percentage of their area, with a negative impact on performance, but they are easy to handle. In moderate/heavy air use a vang and the outhaul to tighten them down, but in light air, slack the outhaul slightly to allow a fuller shape.
Loose foot
There is really no reason NOT to have a loose footed main. Many sailmakers are now making that their standard unless something different is specifically requested. Trimming is easier, the shape is better, and performance improves because of it. You will see almost nothing but loose footed mains on high tech race boats. The vang and other sail controls work just the same. If you have a loose foot, keep it. If you don't, try it on your next sail. You'll like it.
There is really no reason NOT to have a loose footed main. Many sailmakers are now making that their standard unless something different is specifically requested. Trimming is easier, the shape is better, and performance improves because of it. You will see almost nothing but loose footed mains on high tech race boats. The vang and other sail controls work just the same. If you have a loose foot, keep it. If you don't, try it on your next sail. You'll like it.
Did you search our archives???
You will probably find a ton of information there on this very topic. Cheers,
You will probably find a ton of information there on this very topic. Cheers,
Its all in the Cloth
My UK built non-loose footed full roach fully battened mainsail was very flat at the bottom so I asked the designer whether it would be okay to run it loose footed because they had put such a thick bolt rope that it was impossible to stretch or compress it to alter the draft. He replied that the sail would be just fine and that the clew would be strong enough to take the loads. So I did it. Disaster, the sail was dacron and old. The resination in the cloth had partially broken down and, though I could get plenty of draft in the lower third, the cloth moved on the bias and it developed a fullness - read bag - in the top third which was impossible to get rid of. We had to go back to putting the bolt rope into the boom. The racers use high tech cloth with kevlar or similar reinforcement strands glued on in a stress map to prevent the cloth from changing shape on the bias. IMHO only sails designed to be loose footed should be used this way. The loose foot allows draft control from mid height downwards but it looses a little bit of air through the gap where the sail has no 'shelf' to form an end plate.
My UK built non-loose footed full roach fully battened mainsail was very flat at the bottom so I asked the designer whether it would be okay to run it loose footed because they had put such a thick bolt rope that it was impossible to stretch or compress it to alter the draft. He replied that the sail would be just fine and that the clew would be strong enough to take the loads. So I did it. Disaster, the sail was dacron and old. The resination in the cloth had partially broken down and, though I could get plenty of draft in the lower third, the cloth moved on the bias and it developed a fullness - read bag - in the top third which was impossible to get rid of. We had to go back to putting the bolt rope into the boom. The racers use high tech cloth with kevlar or similar reinforcement strands glued on in a stress map to prevent the cloth from changing shape on the bias. IMHO only sails designed to be loose footed should be used this way. The loose foot allows draft control from mid height downwards but it looses a little bit of air through the gap where the sail has no 'shelf' to form an end plate.
You are right on Domalex
A loose footed sail has no camber built into it like a sail that is attached to the boom. If you use a sail with camber built in as a loose footed one it WILL still have camber even when the luft, leach, and foot are all straight as an arrow. This is the only way a boom footed sail can have camber. A loose footed sail also suffers from clew strain. When new that is no problem but as the sail ages the clew is so highly stressed it is the first part to fail and that failure results in no sail at all. A boomed sail spreads the forces out over the entire foot and so will probably last longer and if the clew does fail you would still be able to use the main. They do set easier and if properly designed even are a good design for a storm sail.
A loose footed sail has no camber built into it like a sail that is attached to the boom. If you use a sail with camber built in as a loose footed one it WILL still have camber even when the luft, leach, and foot are all straight as an arrow. This is the only way a boom footed sail can have camber. A loose footed sail also suffers from clew strain. When new that is no problem but as the sail ages the clew is so highly stressed it is the first part to fail and that failure results in no sail at all. A boomed sail spreads the forces out over the entire foot and so will probably last longer and if the clew does fail you would still be able to use the main. They do set easier and if properly designed even are a good design for a storm sail.
What in hell are you talking about??
Loose footed mainsail with no camber??? Boomed mainsail will last longer??? Questions for you - What do all the Lasers at the local and Olympic level use??? What do the majority of the big one design racing classes use - loose footed or boom bolts???
Loose footed mainsail with no camber??? Boomed mainsail will last longer??? Questions for you - What do all the Lasers at the local and Olympic level use??? What do the majority of the big one design racing classes use - loose footed or boom bolts???
Huh?
Most certainly a loose footed sail has camber built into it ... the very same 'broadseaming' that a 'shelf footed" sail has. The ONLY difference will be the shape (or not) of the shelffoot with a boltrope. As regards, 'clew strain' both sails will have the exact strain (forces) in the horizontal plane acting on the clew. A loosefooted sail will have at least a very large single slug which will be attached to the boom groove (which takes all the vertical components of force acting on the clew. . A loosefooted sail will have infinitely more ability for adjustability, principally the ability to be further 'flattened', or to provide maximum draft, etc. especially in the lower panels of the sail. Choose a looose footed sail over a shelf-footed sail for its greater adjustability. hope this helps
Most certainly a loose footed sail has camber built into it ... the very same 'broadseaming' that a 'shelf footed" sail has. The ONLY difference will be the shape (or not) of the shelffoot with a boltrope. As regards, 'clew strain' both sails will have the exact strain (forces) in the horizontal plane acting on the clew. A loosefooted sail will have at least a very large single slug which will be attached to the boom groove (which takes all the vertical components of force acting on the clew. . A loosefooted sail will have infinitely more ability for adjustability, principally the ability to be further 'flattened', or to provide maximum draft, etc. especially in the lower panels of the sail. Choose a looose footed sail over a shelf-footed sail for its greater adjustability. hope this helps
Mis-information
It's sometimes tough to separate accurate knowledgeable expertise based on experience from what might just be personal opinion. The Owner Profiles give the chance to evaluate the posters background and experience to see how it might back up the opinions being offered.
It's sometimes tough to separate accurate knowledgeable expertise based on experience from what might just be personal opinion. The Owner Profiles give the chance to evaluate the posters background and experience to see how it might back up the opinions being offered.
think about it
There's no more strain on the clew of a loose-footed main than there is on the clew of a loose-footed jib. And there's no less camber on a loose-footed main than there is on a loose-footed jib.
There's no more strain on the clew of a loose-footed main than there is on the clew of a loose-footed jib. And there's no less camber on a loose-footed main than there is on a loose-footed jib.
I had my sailmaker convert my foot Bolt rope main
to a loose footed main and it was the best easiest sail modification I ever made. My sailmaker explained there were no concerns and its been fine (7 year old main - and as Rich said there is less strain than even the Jib clew as there is a slug on the boom in the to hold the sail down and out) ) I have a traditional Main, not a roller furling main. (Catalina 36) Do not confuse Roller furling main (aka no roach main) with loose footed. Yes most all furler mainsails are loose footed (unless boom furled), but many traditional mains are loose footed. I dare say most could be easily converted. When I had the Bolt rope main (in the foot) on my boat it was very difficult to adjust outhaul to add belly in the main. Once I converted to a loose footed main it was very easy to adjust the foot of the sail (I brought outhaul to cockpit). This can move the center of effort (belly) of the lower part of the sail as needed. I was also concerned that my traditional main would still work with the Dutchman sail flaking system and the sailmaker said just pull the outhaul tight and it'll work the same and he was right.
to a loose footed main and it was the best easiest sail modification I ever made. My sailmaker explained there were no concerns and its been fine (7 year old main - and as Rich said there is less strain than even the Jib clew as there is a slug on the boom in the to hold the sail down and out) ) I have a traditional Main, not a roller furling main. (Catalina 36) Do not confuse Roller furling main (aka no roach main) with loose footed. Yes most all furler mainsails are loose footed (unless boom furled), but many traditional mains are loose footed. I dare say most could be easily converted. When I had the Bolt rope main (in the foot) on my boat it was very difficult to adjust outhaul to add belly in the main. Once I converted to a loose footed main it was very easy to adjust the foot of the sail (I brought outhaul to cockpit). This can move the center of effort (belly) of the lower part of the sail as needed. I was also concerned that my traditional main would still work with the Dutchman sail flaking system and the sailmaker said just pull the outhaul tight and it'll work the same and he was right.
Loose Footed Mainsail Better
Probably not for all aplications, but it is definately something to talk to a sailmaker about. When I replace the original main on my C36, I will go to a 'Shelf footed main' because of my experience with footless, shelfless, and one with a shelf at the foot. I am not saying one is better than the other, but that I have experience with all four (shapeless furling main), and I prefer the shelf footed main for performance.
Probably not for all aplications, but it is definately something to talk to a sailmaker about. When I replace the original main on my C36, I will go to a 'Shelf footed main' because of my experience with footless, shelfless, and one with a shelf at the foot. I am not saying one is better than the other, but that I have experience with all four (shapeless furling main), and I prefer the shelf footed main for performance.
Vangs for safety
An awful lot of the general-purpose cruising boats sold over the years in the US had sailplans designed to conform to whatever racing rules and practices were current at the time of manufacture in order to allow for the needs of weekend racer/cruisers. There seems to be a growing interest in maximizing cruising performance today, and people who are having a new sail made are trying out loose-footed configurations and liking them. On my Long Island Sound zone the wind dies at 4pm and stays dead until 6--a loose-footed main would be a welcome feature over a long Summer. A loose-footed main and a working jib instead of a tiny, tight IOR main and a huge genoa is a lot more comfortable rig for lazy cruising. I consider a boom vang, especially a rigid one, to be a safety feature as much as a sailtrim feature (keeps jibing under control) and wouldn't be without one.
An awful lot of the general-purpose cruising boats sold over the years in the US had sailplans designed to conform to whatever racing rules and practices were current at the time of manufacture in order to allow for the needs of weekend racer/cruisers. There seems to be a growing interest in maximizing cruising performance today, and people who are having a new sail made are trying out loose-footed configurations and liking them. On my Long Island Sound zone the wind dies at 4pm and stays dead until 6--a loose-footed main would be a welcome feature over a long Summer. A loose-footed main and a working jib instead of a tiny, tight IOR main and a huge genoa is a lot more comfortable rig for lazy cruising. I consider a boom vang, especially a rigid one, to be a safety feature as much as a sailtrim feature (keeps jibing under control) and wouldn't be without one.
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