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#11
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An amphibian that sank?
The only unsinkable boat I know about is the Boston Whaler
www.whaler.com which is made of two fiberglass shells bonded together with the inside filled 100% with foamed in-place resin that makes it one solid boat. They even can be cut into sections and the still get you to shore with dry feet. But aluminum floats don't work well with foam inside because of corrosion between the foam and metal. A better solution is to fill the compartments with ping-pong balls. They displace water, don't weigh too much and can be removed for inspection and corrosion control. -- James H. Macklin ATP,CFI,A&P -- The people think the Constitution protects their rights; But government sees it as an obstacle to be overcome. some support http://www.usdoj.gov/olc/secondamendment2.htm See http://www.fija.org/ more about your rights and duties. "Morgans" wrote in message ... | | "Flyingmonk" wrote in message | ups.com... | http://www.divingservices.net/aircraft.jpg | http://www.divingservices.net/9bcess2.jpg | | Anyone have the story behind this? Strange that a plane designed to | float, sank! | | You might be surprised how many recreational boats sink. There are dozens | of thing that can happen. Most common are drain plug left out/loose, seals | or hoses leaking and slowly filling the boat. | -- | Jim in NC | |
#12
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An amphibian that sank?
In article ,
"Morgans" wrote: "Roy Smith" wrote One of the fundamental truths of boat design is that the center of gravity has to be lower than the center of bouyancy. If it's not, then eventually the boat (helicopter, whatever) will figure out how to turn itself over so that it is. Not completely true, but right to a degree. In the case of a heli or plane on floats, the center of gravity is way higher than the center of buoyancy, and everything continues to work out OK. In that case the center of gravity is between the outer points of buoyancy. Like this: GGG BB BB Then if it gets a little sideways, and the gravity is on the outside of buoyancy, things will re-adjust. GGG BB BB Ker-splash! Soon it is stable again, but in a bad (g) way: BB BB GGG Exactly. The heli has indeed figured out how to turn itself over and put its CG below its CB. |
#13
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An amphibian that sank?
The only unsinkable boat I know about is the Boston Whaler
www.whaler.com which is made of two fiberglass shells bonded together with the inside filled 100% with foamed in-place resin that makes it one solid boat. They even can be cut into sections and the still get you to shore with dry feet. But aluminum floats don't work well with foam inside because of corrosion between the foam and metal. A better solution is to fill the compartments with ping-pong balls. They displace water, don't weigh too much and can be removed for inspection and corrosion control. -- James H. Macklin ATP,CFI,A&P Some of the small sail boats also have foam filled compartments with the same effect. The name MacGreggor comes to mind from years ago, and there are probably others by now. Peter |
#14
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An amphibian that sank?
Roy Smith wrote:
One of the fundamental truths of boat design is that the center of gravity has to be lower than the center of bouyancy. If it's not, then eventually the boat (helicopter, whatever) will figure out how to turn itself over so that it is. Absolutly wrong. The center of bouyancy of most large boats and ships is well below the center of gravity. -- John (I Took Naval Science) Kimmel GET YER STINKING PAWS OFF ME YOU DAMN DIRTY APE! |
#15
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An amphibian that sank?
"Peter Dohm" wrote:
Some of the small sail boats also have foam filled compartments with the same effect. The name MacGreggor comes to mind from years ago, and there are probably others by now. Barf. Never use "MacGregor" and "sailboat" in the same sentence. They are the most butt-ugly things in the universe. |
#16
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An amphibian that sank?
John Kimmel wrote: Roy Smith wrote: One of the fundamental truths of boat design is that the center of gravity has to be lower than the center of bouyancy. If it's not, then eventually the boat (helicopter, whatever) will figure out how to turn itself over so that it is. Absolutly wrong. The center of bouyancy of most large boats and ships is well below the center of gravity. -- John (I Took Naval Science) Kimmel GET YER STINKING PAWS OFF ME YOU DAMN DIRTY APE! I saw a head-on picture of a carrier and boy did it look top heavy... The Monk GET YER STINKING PAWS OFF ME YOU DAMN DIRTY HUMAN! ~ Panet of the Apes II |
#17
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An amphibian that sank?
"Grumman-581" wrote in message
... "Roy Smith" wrote in message ... 23.751 Main float buoyancy. (a) Each main float must have [...] I don't see anything in there that would require the supposedly watertight compartments to still provide floatation in the event of them no longer being watertight... There's not. However, I have heard of seaplane owners who have done things like fill their wings (or other easily accessed compartments) with ping-pong balls, for this purpose. Generally speaking though, seaplanes don't have any filler material, such as styrofoam or what have you the way boats do. I think it's likely that this is because, as light as styrofoam is, when you fill every empty space of an airplane with it, that's still useful load you lose. Of course, there are also the certification and maintenance issues as well. The bottom line is, I believe, that it's much simpler to put a bunch of lightweight filler material in a boat than in an airplane. Pete |
#18
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An amphibian that sank?
"Roy Smith" wrote in message
... "Peter Dohm" wrote: Some of the small sail boats also have foam filled compartments with the same effect. The name MacGreggor comes to mind from years ago, and there are probably others by now. Barf. Never use "MacGregor" and "sailboat" in the same sentence. They are the most butt-ugly things in the universe. They actually did have a replica of a 19th century pilot boat that I thought was sort of neat, if less than practical, and commercially it was a dismal failure. But I really don't like most of their competitors boats very much either. Peter |
#19
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An amphibian that sank?
Morgans wrote: "Roy Smith" wrote One of the fundamental truths of boat design is that the center of gravity has to be lower than the center of bouyancy. If it's not, then eventually the boat (helicopter, whatever) will figure out how to turn itself over so that it is. Not completely true, but right to a degree. In the case of a heli or plane on floats, the center of gravity is way higher than the center of buoyancy, and everything continues to work out OK. In that case the center of gravity is between the outer points of buoyancy. Like this: GGG BB BB Then if it gets a little sideways, and the gravity is on the outside of buoyancy, things will re-adjust. GGG BB BB Ker-splash! Soon it is stable again, but in a bad (g) way: BB BB GGG -- Jim in NC Uh, Houston, we are in Stable -two. |
#20
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An amphibian that sank?
Peter Dohm wrote: "Roy Smith" wrote in message ... "Peter Dohm" wrote: Some of the small sail boats also have foam filled compartments with the same effect. The name MacGreggor comes to mind from years ago, and there are probably others by now. Barf. Never use "MacGregor" and "sailboat" in the same sentence. They are the most butt-ugly things in the universe. They actually did have a replica of a 19th century pilot boat that I thought was sort of neat, if less than practical, and commercially it was a dismal failure. But I really don't like most of their competitors boats very much either. Peter That must have been the 23 foot. Cute little ship. Right down to the bow sprit. I've been looking at a Catalina Capri 18. Can't decide if it's too big, or too small, or just right... Richard |
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