Technology and Operations
This forum is for discussing technological & operational matters pertaining to U-boats.
Re: Air Conditioning on Type XXI's ?
Posted by:
Christopher Tarana
()
Date: June 23, 2002 10:32PM
J.T. McDaniel wrote:
>
> The latest research, which seems to have gone back to older
> sources, suggests Turtle used water ballast, but not a
> ballast tank. The operator just let water into the bottom of
> the hull. There was also 200 pounds of lead that could be
> dropped, attached to a 50 foot rope to allow recovery. It
> appears that Sgt Lee attacked HMS Eagle with his feet wet.
I must have a drier version of the Turtle, if you are interested
in seeing the .bmp I just finished you can email me at
tarana@bluemarble.net The version I had shows a ballast
tank at the bottom.
>
> A major difference between Turtle and Hunley was that Turtle
> would flood down to as close to neutral buoyancy as possible,
> then use an uphaul/downhaul screw to change depth, while
> Hunley used planes. A lot of research subs use a modern
> version of the Turtle's screws, since it allows depth
> adjustment without the need for the boat to be moving.
I noticed that too. I also noticed that some sources showed
them as big beefy "screws" and others show light weight blades
like an airplane propeller. I tend to think the beefy screws may have been
harder to manufacture back then. I can see a black smith making the
light weight blades easily. Though I wonder how much 'bite' either
had in the water.
Christopher
>
> The latest research, which seems to have gone back to older
> sources, suggests Turtle used water ballast, but not a
> ballast tank. The operator just let water into the bottom of
> the hull. There was also 200 pounds of lead that could be
> dropped, attached to a 50 foot rope to allow recovery. It
> appears that Sgt Lee attacked HMS Eagle with his feet wet.
I must have a drier version of the Turtle, if you are interested
in seeing the .bmp I just finished you can email me at
tarana@bluemarble.net The version I had shows a ballast
tank at the bottom.
>
> A major difference between Turtle and Hunley was that Turtle
> would flood down to as close to neutral buoyancy as possible,
> then use an uphaul/downhaul screw to change depth, while
> Hunley used planes. A lot of research subs use a modern
> version of the Turtle's screws, since it allows depth
> adjustment without the need for the boat to be moving.
I noticed that too. I also noticed that some sources showed
them as big beefy "screws" and others show light weight blades
like an airplane propeller. I tend to think the beefy screws may have been
harder to manufacture back then. I can see a black smith making the
light weight blades easily. Though I wonder how much 'bite' either
had in the water.
Christopher
