RC submarine lateral stabilization structure
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Nate
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I, personally, love that Sam has shared this bit of marine physics with us. I completely understand the reasoning behind it and how it applies in real life. Again, the scale application may be different, but the physics are sound.
To simplify for anyone not following, adding external keels has a twofold benefit. First off, it provides a surface that water acts against to improve stability of the boat if an outside force (such as wind) creates a rotational force about the longitudinal axis of the boat. The water reduces the ability of the wind to accelerate the mass of the hull, dampening the effect.
Secondly, moving the weight of these keels from inside to outside increases the moment arm for the weights, thereby increasing their effectiveness at stabilizing the boat. The caveat to this is that putting them at 45 degrees to the vertical centerline, as Sam suggested, reduces their effectiveness at increasing static stability. You'd need double the weight to create the same static stability. More effective would be an external bilge keel placed in line with the center of buoyancy and the center of mass.
At the end of the day, we are somewhat hampered in playing around with this as we are, for the most part, trying to create scale replicas of existing boats, and are thereby limited in terms of external modifications.
BobComment
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I, personally, love that Sam has shared this bit of marine physics with us. I completely understand the reasoning behind it and how it applies in real life. Again, the scale application may be different, but the physics are sound.
To simplify for anyone not following, adding external keels has a twofold benefit. First off, it provides a surface that water acts against to improve stability of the boat if an outside force (such as wind) creates a rotational force about the longitudinal axis of the boat. The water reduces the ability of the wind to accelerate the mass of the hull, dampening the effect.
Secondly, moving the weight of these keels from inside to outside increases the moment arm for the weights, thereby increasing their effectiveness at stabilizing the boat. The caveat to this is that putting them at 45 degrees to the vertical centerline, as Sam suggested, reduces their effectiveness at increasing static stability. You'd need double the weight to create the same static stability. More effective would be an external bilge keel placed in line with the center of buoyancy and the center of mass.
At the end of the day, we are somewhat hampered in playing around with this as we are, for the most part, trying to create scale replicas of existing boats, and are thereby limited in terms of external modifications.
Bob
The HMS Holland l That I am currently build has these keel faring's on both sides of the hull.
Rob
"Firemen can stand the heat"
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