|
In a message dated 3/10/2010 1:05:31 P.M. Pacific Standard Time,
hc.fulton@gmail.com writes:
Hi Hugh. Good to hear from you.
On the hose thing.....
Yes, I was originally planning on using a HP hydraulic hose like used
on a back hoe, ( to eliminate using a pipe union ) but as Vance said,
rubber maybe ain't so good. Yes, it's strong enough, but may corrode.
If I can't find a deal on Swagelock parts, I'll stay with schedule 40 SS
fittings. I'm not too worried about a little weeping down the road. Adding
another hull stop valve right at the thru-hull nipple before the HP air
line taps in is an acceptable redundancy item that's low cost. My motivation
here is to be able to get a pipe wrench on the pipe line while submerged. Not a
likely scenario, but easily accomplished.
On the depth thing......
Where is my math screwed up ? Apart from small differences in salinity,
temperature, etc. the calc is pretty straightforward. Alec got me thinking I
have been making a mistake all this time but I just checked it on Google and the
basic idea is right. Pressure = (depth divided by 33) X 14.7
psi.
OK, it's roughly half the depth. ( 112 psi @ 250 ft. )
It's funny, I was checking Google for the formula and got a NASA site. To
determine pressure at depth they use a complicated formula using weight of water
and a bunch of other stuff, of course all in metric terms.
No wonder a wrench is $4000......
I did some work for NASA years ago and they seem to go out of their way to
make things complicated. My original contract was to be 3 weeks and
about $45,000.
I ended up there 13 months and $1.3 million. Those guys crack me up. At
NASA, I guess if you don't spend it you don't get it next budget cycle.
Me, I'm just a simple guy.
Frank D.
|