I was a boomless cat sailor for years and now own a monohaul. I am upgrading the sails and gear on board. So far I have added a travler track/car with an 8-1 outhaul and I have added a 8-1 cunnningham. The boat didnt come with a boom vang nor an adjustable backstay but am thinking about adding them. I just changed my main to a new loose foot tri-radial main, but for the life of me, I cant seem to picture what the vang will do for me now that the foot is not attached to the boom. Besides controlling the boom down wind what does the vang do for sail trim on different points of sail? What will an adjustable back stay do for the main and for the headsail? ted
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Tuna sail?
Ted, Here's a basic article on fractional rig tuning that may help some. (related link) Happy sails, MArk
Ted, Here's a basic article on fractional rig tuning that may help some. (related link) Happy sails, MArk
Controls shape of Main
Ted The vang seems to predominately control the leech tension, the halyard &/or cunningham the luff tension, and the outhaul the foot tension. The traveler allows proper positioning of the boom once the shape is set. Not suprisingly, these adjustments interact with each other -- such as establishing the degree of twist, the chord dimensions, etc. The combo of the vang and outhaul will serve to flatten (or not) the sail on all points, even with a loose foot. --Ron
Ted The vang seems to predominately control the leech tension, the halyard &/or cunningham the luff tension, and the outhaul the foot tension. The traveler allows proper positioning of the boom once the shape is set. Not suprisingly, these adjustments interact with each other -- such as establishing the degree of twist, the chord dimensions, etc. The combo of the vang and outhaul will serve to flatten (or not) the sail on all points, even with a loose foot. --Ron
Backstay Adjuster
Ted, you may try Gaerhauer for a rigid boom vang, I have one on my Catalina 320 which I race and it works great.I just aded a Backstay Adjuster as well and really like it. Upwind trim it in to reduce forestay sag, flatten the sails if need and point higher. Off the wind is faster too as we ease the adjuster to give a fuller shape to both main & Genoa.If you race you will need both.
Ted, you may try Gaerhauer for a rigid boom vang, I have one on my Catalina 320 which I race and it works great.I just aded a Backstay Adjuster as well and really like it. Upwind trim it in to reduce forestay sag, flatten the sails if need and point higher. Off the wind is faster too as we ease the adjuster to give a fuller shape to both main & Genoa.If you race you will need both.
More on vang and mainsail trim
As mentioned in the previous posts, as the vang pulls the boom down, it also pulls the clew of the mainsail down, and tensions the leech. It works the same whether the mainsail is loose-footed or not. Going downwind, this downward pull stops the boom from rising and presents the maximum sail area to the wind. The vang also has an effect when going upwind, but is usually overridden by the downward pull of the mainsheet, especially when sailing close-hauled. A tight leech is harder for the wind to deform so the wind is deflected further aft as it passes over the mainsail. This creates a force on the sail that tries to turn the bow of the boat more into the wind...an effect called weather helm. A tight leech is not the only cause of weather helm, but in my opinion it is one of the most significant. A little weather helm is good because it gives the helm some "feel", creates hydrodynamic lift and forces the boat to turn up into the wind automatically and stop if you lose control of the helm. Too much weather helm creates drag and can slow the boat because the rudder has to be angled more than it needs to be in order to maintain course. An adjustable backstay is very useful as it does two things to the mainsail at once. Tensioning the backstay bends the mast like a bow, i.e. the masthead moves aft and the middle of the mast moves forward. Moving the masthead aft eases leech tension, which deflects airflow over the mainsail less and decreases weather helm. Moving the middle of the mast forward tightens and flattens the mainsail, reducing power. The backstay is the primary adjustment for reducing power and heel when racing upwind in heavy air. When cruising, reefing is probably the more prudent way to reduce power and heel, but a lot will depend on your experience, the sea state, weather and other conditions at the time. Good luck! Peter H23 "Raven"
As mentioned in the previous posts, as the vang pulls the boom down, it also pulls the clew of the mainsail down, and tensions the leech. It works the same whether the mainsail is loose-footed or not. Going downwind, this downward pull stops the boom from rising and presents the maximum sail area to the wind. The vang also has an effect when going upwind, but is usually overridden by the downward pull of the mainsheet, especially when sailing close-hauled. A tight leech is harder for the wind to deform so the wind is deflected further aft as it passes over the mainsail. This creates a force on the sail that tries to turn the bow of the boat more into the wind...an effect called weather helm. A tight leech is not the only cause of weather helm, but in my opinion it is one of the most significant. A little weather helm is good because it gives the helm some "feel", creates hydrodynamic lift and forces the boat to turn up into the wind automatically and stop if you lose control of the helm. Too much weather helm creates drag and can slow the boat because the rudder has to be angled more than it needs to be in order to maintain course. An adjustable backstay is very useful as it does two things to the mainsail at once. Tensioning the backstay bends the mast like a bow, i.e. the masthead moves aft and the middle of the mast moves forward. Moving the masthead aft eases leech tension, which deflects airflow over the mainsail less and decreases weather helm. Moving the middle of the mast forward tightens and flattens the mainsail, reducing power. The backstay is the primary adjustment for reducing power and heel when racing upwind in heavy air. When cruising, reefing is probably the more prudent way to reduce power and heel, but a lot will depend on your experience, the sea state, weather and other conditions at the time. Good luck! Peter H23 "Raven"
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