True or false? To sail to weather well, a centerboard boat (due to its underwater foil being long and narrow) must have a relatively higher speed, than a shoal keel, fin keel or full keel boat?
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to weather well
My first big water boat was an Endeavor 26' made by W.D. Shock. It had a full keel and was in the grove with heavy winds the best on the wind boat I have ever sailed. Fast and stable. "Sailing well" to the wind is all about what's under the boat. In this case more is better.
My first big water boat was an Endeavor 26' made by W.D. Shock. It had a full keel and was in the grove with heavy winds the best on the wind boat I have ever sailed. Fast and stable. "Sailing well" to the wind is all about what's under the boat. In this case more is better.
Full keelers
these boats do find the groove nicely when going to weather - you almost have to be dead not to be able to feel it. The problem is, of course, they are not pointing nearly as high as the fin keelers nor as fast through the water. I know I have ignored the original post, but I don't know the answer.
these boats do find the groove nicely when going to weather - you almost have to be dead not to be able to feel it. The problem is, of course, they are not pointing nearly as high as the fin keelers nor as fast through the water. I know I have ignored the original post, but I don't know the answer.
Longer thinner is better
A longer thinner keel is better for going into the wind. BUT ballast to hold the sails upright is also important. The lower the ballast the better. So a boat with a long keel and a lot of ballast as low as possible should go to weather better. BUT a boat is a collection of things that affect performance. My sheeting angle on my jib limits my upwind performance.... Also in rough seas the dynamics are different than in smooth seas. A fat hull is harder to push through waves than a thin hull. A fat flat hull is stiffer in flat water than a deep thin hull. My old Mac 26 would go to weather pretty well with the daggerboard down in low wind flat water. As the wind increased it wasn't stiff enough to go to weather well. It did OK.
A longer thinner keel is better for going into the wind. BUT ballast to hold the sails upright is also important. The lower the ballast the better. So a boat with a long keel and a lot of ballast as low as possible should go to weather better. BUT a boat is a collection of things that affect performance. My sheeting angle on my jib limits my upwind performance.... Also in rough seas the dynamics are different than in smooth seas. A fat hull is harder to push through waves than a thin hull. A fat flat hull is stiffer in flat water than a deep thin hull. My old Mac 26 would go to weather pretty well with the daggerboard down in low wind flat water. As the wind increased it wasn't stiff enough to go to weather well. It did OK.
Yes and No ... depends on the shapes, etc.
Usually a deep fin keel (with bulb) is faster and can usually point much higher than all the other types because the keel (if the boat is properly sailed) can generate a great deal of 'lift'. The bottom bulb allows ballast to be carried at the very bottom for best mathematical advantage and also tends to prevent tip vortices (parasitic turbulance) at the very end of the foil. A centerboard will usually have the ballast more evenly distributed (less mechanical advantage), will not be able to have the bulb/winglets, etc. hence more drag from tip vortices, will usually not be shaped to the hydrodynamically relatively perfect foil shapes (NACA010xxx, etc. series of foils) PLUS there will be a HUGE hull discontinuity of hull shape at the 'entrance' to the centerboard trunk for additional hull drag ...... and if the centerboard trunk is not sealed against atmospheric air will cause air to be sucked down the trunk and the centerboard will begin to easily cavitate FALSE !!!!!!!!!!!
Usually a deep fin keel (with bulb) is faster and can usually point much higher than all the other types because the keel (if the boat is properly sailed) can generate a great deal of 'lift'. The bottom bulb allows ballast to be carried at the very bottom for best mathematical advantage and also tends to prevent tip vortices (parasitic turbulance) at the very end of the foil. A centerboard will usually have the ballast more evenly distributed (less mechanical advantage), will not be able to have the bulb/winglets, etc. hence more drag from tip vortices, will usually not be shaped to the hydrodynamically relatively perfect foil shapes (NACA010xxx, etc. series of foils) PLUS there will be a HUGE hull discontinuity of hull shape at the 'entrance' to the centerboard trunk for additional hull drag ...... and if the centerboard trunk is not sealed against atmospheric air will cause air to be sucked down the trunk and the centerboard will begin to easily cavitate FALSE !!!!!!!!!!!
Yes, I believe is true.
A center board carries no ballast weight and its sole purpose is regulate sideway slipage. The larger the lateral surface the better it will control that slipage. For that reason boards are quite long as by design they have to be thin to be able to be retracted into the underside. Speed accomplishes the function of enlarging the effect of lateral forces in the water for the thin boards. I guess you can say that the faster the boat goes the better it will point to weather. This to some extent is true for everyboat but much more for a centerboard one.
A center board carries no ballast weight and its sole purpose is regulate sideway slipage. The larger the lateral surface the better it will control that slipage. For that reason boards are quite long as by design they have to be thin to be able to be retracted into the underside. Speed accomplishes the function of enlarging the effect of lateral forces in the water for the thin boards. I guess you can say that the faster the boat goes the better it will point to weather. This to some extent is true for everyboat but much more for a centerboard one.
Thanks
Thanks. It looks like the centerboard must obtain a higher speed to generate the same amount of lift as an underwater foil of greater area. So if you want to point with a centerboard, the saying “speed first, point second" is even more true than with other types of keels.
Thanks. It looks like the centerboard must obtain a higher speed to generate the same amount of lift as an underwater foil of greater area. So if you want to point with a centerboard, the saying “speed first, point second" is even more true than with other types of keels.
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