Re: HP, weight and visability

[Ray Keefer <Ray.Keefer@eng.Sun.COM>]

Hi,

> An inner hull of 1/2 inch and outer of 1/4 inch. The space between the
> two will be used as soft ballast (or open to the environment). I was going
> to give the outer hull the thicker hull and use that as the pressure hull
> but that forces the issue of pumping out the water if I want to use it as a
> ballast. If not then it would be better to give the outer hull the thicker
> hull and use the supports holding the inner hull for reinforcing beams for
> the outer. Having the inner hull as the pressure hull also allows me the
> luxury of a safety shell before anything makes it to the inner main pressure
> hull. 
>  
>      Any thoughts from anyone? So many things to consider... 

1. What is that spacing between the hulls? 3", 6", 12"? You will need access
   between the hull layers to paint the bare metal or your hull will rust.
   One option is to make the outer hull removible but then you have to 
   worry about creating an air tight seal when assembled.

2. Welding a dual layered hull is awkward, especially if the spacing is small.

3. Pumping water out of an inner hull tank is doable. That is how the big
   boys work. You will need a pump capible of pumping directly out to sea
   pressure, have piping rigid enough restand the sea pressure and a shut
   off valve as close to the seaward side of the piping that you can.

4. An alternative to pumping is to create an internal tank that you can feed
   compressed air into. The air will drive water out. The tank will have to
   take the pressure and the piping will have to be substantial.

Regards,
Ray