I recently read an article suggesting that sailing with the genny only puts undue stress on the rigging, particularly the backstay. It recommends using both sails(main & genny)to "balance" the load on the rigging. I love sailing with just the headsail. Am I damaging, or at least stressing, my rigging ('72 Catalina 27')?
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Un Scientific
Harry, My feeling is that sailing with an genny alone may cause undo stress on the rigging souds very un sceintific. If I think about it, the more sail you have up the more energy you are transferring through the rig. When you have your main up, the stresses on the rig do not balance out, however they do add together in terms of vectors; that is, both force and direction. I can imagine there is some counterblancing of forces going on. I would be willing to bet they in no way significantly compare to the forces of sailing with the entire sail plan up. IMHO, Mike D
Harry, My feeling is that sailing with an genny alone may cause undo stress on the rigging souds very un sceintific. If I think about it, the more sail you have up the more energy you are transferring through the rig. When you have your main up, the stresses on the rig do not balance out, however they do add together in terms of vectors; that is, both force and direction. I can imagine there is some counterblancing of forces going on. I would be willing to bet they in no way significantly compare to the forces of sailing with the entire sail plan up. IMHO, Mike D
Thuings we know that just ain't so
The theory is that with the main sail up you get support for the mast all along the luff of the sail. But this looks to be one of those things where the theory looks right but just ain't so, like bumblebees flying. I have never heard of a documented case of a dismasting because only the jib was in use. Think about it. No matter what sails you have set or what angle of attack, the resultant force is forward. The jib is pulling the mast forward and the main is pushing it. The mast is restrained by the backstay and the after shrouds. If you have a topping lift to the end of the boom and thence to the traveller, there is additional after restraint. As you ease the main, there is less and less restraint from the mainsheet and traveller until you are running downwind wing-and-wing and the backstay is taking ALL the force. The mainsail provides no support whatever. So you would reduce the load by striking the main. Being lazy, we too often sail with only the genny, especially on hot days when setting the main requires striking the bimini. This, of course, does not in any way influence my opinion in the matter.
The theory is that with the main sail up you get support for the mast all along the luff of the sail. But this looks to be one of those things where the theory looks right but just ain't so, like bumblebees flying. I have never heard of a documented case of a dismasting because only the jib was in use. Think about it. No matter what sails you have set or what angle of attack, the resultant force is forward. The jib is pulling the mast forward and the main is pushing it. The mast is restrained by the backstay and the after shrouds. If you have a topping lift to the end of the boom and thence to the traveller, there is additional after restraint. As you ease the main, there is less and less restraint from the mainsheet and traveller until you are running downwind wing-and-wing and the backstay is taking ALL the force. The mainsail provides no support whatever. So you would reduce the load by striking the main. Being lazy, we too often sail with only the genny, especially on hot days when setting the main requires striking the bimini. This, of course, does not in any way influence my opinion in the matter.
We do it all the time!
We sail a lot with just our jib and there are lots of other sailors who do the same. If I remember, the danger is with boats having only a single lower shroud supporting the mast.
We sail a lot with just our jib and there are lots of other sailors who do the same. If I remember, the danger is with boats having only a single lower shroud supporting the mast.
Mid-Mast can buckle back
The article in Sail this month describes it. The genny pulls the mast head forward while the lowers pull it back without the main to even the stress. Like all rig stress issues, you wouldn't see the problem unless you got hit by a sustained gust, or some other extreme condition. Most long term cruisers have several stories about such incidents. The point is that you are raising the risk of buckling your stick when you experience _your_ story. (Every authoritative seamanship book I've read agrees on this point, by the way) David Lady Lillie
The article in Sail this month describes it. The genny pulls the mast head forward while the lowers pull it back without the main to even the stress. Like all rig stress issues, you wouldn't see the problem unless you got hit by a sustained gust, or some other extreme condition. Most long term cruisers have several stories about such incidents. The point is that you are raising the risk of buckling your stick when you experience _your_ story. (Every authoritative seamanship book I've read agrees on this point, by the way) David Lady Lillie
Response to David
David, I have both heard and read of some of the stories which you mention. I respect the opinions of the many who have learned from first hand experience. I just challenge the scientific control of the matter at hand. Would the boats whose mast buckled due to flying just the genny have been totally dismasted should they have had their entire sail plan employed instead? Or maybe a knockdown? Of course my reply to my own question is we'll never know the truth of the matter!!!! respectfully, Mike D
David, I have both heard and read of some of the stories which you mention. I respect the opinions of the many who have learned from first hand experience. I just challenge the scientific control of the matter at hand. Would the boats whose mast buckled due to flying just the genny have been totally dismasted should they have had their entire sail plan employed instead? Or maybe a knockdown? Of course my reply to my own question is we'll never know the truth of the matter!!!! respectfully, Mike D
Seamanship is about risks
Day sailing, we can take bigger risks - we have good chances to see the weather radar before we go, and to make it back to shelter if a surprise storm shows up. Coastal cruising, we _will_ eventually experience extreme weather that comes up too fast to escape. A knock-down or scary period on a lee shore are are stories I have heard. Ocean cruising means we have to take whatever comes - despite the best calculation of "weather windows." When we are cruising on the Great Lakes, I enjoy knowing the best preparations we can make, and how they increase our odds of dealing with the unexpected. For the same reason, I understand when we take risks, and what the possible consequences are. When I sail with a foresail only (seldom, but sometimes) I know that my mast is at greater risk - not a great risk, just a greater one. David Lady Lillie
Day sailing, we can take bigger risks - we have good chances to see the weather radar before we go, and to make it back to shelter if a surprise storm shows up. Coastal cruising, we _will_ eventually experience extreme weather that comes up too fast to escape. A knock-down or scary period on a lee shore are are stories I have heard. Ocean cruising means we have to take whatever comes - despite the best calculation of "weather windows." When we are cruising on the Great Lakes, I enjoy knowing the best preparations we can make, and how they increase our odds of dealing with the unexpected. For the same reason, I understand when we take risks, and what the possible consequences are. When I sail with a foresail only (seldom, but sometimes) I know that my mast is at greater risk - not a great risk, just a greater one. David Lady Lillie
Sail pull on mast not simply forward......
This is an interesting topic which returns every few months or so. The original poster is likely to learn far more by simply searching the archives. However, freshly served half-truths may appear more tantalizing to newcomers than stale truths. Therefore, it behoves all of us to keep responding as best as we can. In the current thread I find myself in full agreement with David. Peter simplifies things a little too far by writing: "Think about it. No matter what sails you have set or what angle of attack, the resultant force is forward. The jib is pulling the mast forward and the main is pushing it" The fact is that on all points of sail but a dead downwind run the direction of the sail-transmitted wind forces on the mast has a marked sideways component as well. In fact, when close-hauled the resultant force on the mast is much more sideways than forward, causing a vessel without keel, centerboard or leeboard to scud off sideways and make little or no headway. It is the interplay between the sail-transmitted forces (not only on the mast but also on the sheet attachment points) and the strong resistance of underwater appendages such as keel and/or boards (and, in fact, the u/w section of the hull itself) to sideways movement that produces a net resultant force with a dominant forward component. This is why the use of running backstays (which pull the mast aft as well as sideways) has traditionally been the preferred method of reinforcing the mast in strong winds, especially in case an inner forestay pulls on the mast without directly opposing pull from shrouds or mainsail. On Rivendel II we ALWAYS set the specially installed running backstays when making a longer passage in strong winds, particularly when flying our inner headstay mounted staysail. When flying both jibs wing-on-wing on a nearly dead downwind run we use both running backstays. Flying Dutchman "Rivendel II" (Legend 43; currently dry-berthed in Port Vila for the cyclone season)
This is an interesting topic which returns every few months or so. The original poster is likely to learn far more by simply searching the archives. However, freshly served half-truths may appear more tantalizing to newcomers than stale truths. Therefore, it behoves all of us to keep responding as best as we can. In the current thread I find myself in full agreement with David. Peter simplifies things a little too far by writing: "Think about it. No matter what sails you have set or what angle of attack, the resultant force is forward. The jib is pulling the mast forward and the main is pushing it" The fact is that on all points of sail but a dead downwind run the direction of the sail-transmitted wind forces on the mast has a marked sideways component as well. In fact, when close-hauled the resultant force on the mast is much more sideways than forward, causing a vessel without keel, centerboard or leeboard to scud off sideways and make little or no headway. It is the interplay between the sail-transmitted forces (not only on the mast but also on the sheet attachment points) and the strong resistance of underwater appendages such as keel and/or boards (and, in fact, the u/w section of the hull itself) to sideways movement that produces a net resultant force with a dominant forward component. This is why the use of running backstays (which pull the mast aft as well as sideways) has traditionally been the preferred method of reinforcing the mast in strong winds, especially in case an inner forestay pulls on the mast without directly opposing pull from shrouds or mainsail. On Rivendel II we ALWAYS set the specially installed running backstays when making a longer passage in strong winds, particularly when flying our inner headstay mounted staysail. When flying both jibs wing-on-wing on a nearly dead downwind run we use both running backstays. Flying Dutchman "Rivendel II" (Legend 43; currently dry-berthed in Port Vila for the cyclone season)
You're right
of course. I did oversimplify. But it doesn't really matter. The resultant is still forward and any thwartship component will be taken by the shrouds with little help from the main. So close hauled with only the jib the forward load on the backstay is less and assisted by the windward shrouds. Watch them leeward shrouds go slack. Running backstays are very nice but a bit of a hassle. And of course when you talk about running downwind with two jibs wing and wing for days on end -- well! Seems to me the important thing is to ensure that the mast never goes out of column, which means a properly designed and tuned rig in the first place.
of course. I did oversimplify. But it doesn't really matter. The resultant is still forward and any thwartship component will be taken by the shrouds with little help from the main. So close hauled with only the jib the forward load on the backstay is less and assisted by the windward shrouds. Watch them leeward shrouds go slack. Running backstays are very nice but a bit of a hassle. And of course when you talk about running downwind with two jibs wing and wing for days on end -- well! Seems to me the important thing is to ensure that the mast never goes out of column, which means a properly designed and tuned rig in the first place.
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