[PSUBS-MAILIST] Closed view

[Alec Smyth via Personal_Submersibles]

Hank, I should mention that although Shackleton's valves were originally to
use bleed-driven closing, I ended up canceling that feature and instead
plumbed them for manual actuation in both directions. I made the change
because, although they have a spring to make them NC, I liked the idea of
clamping with air for a more positive seal, and I didn't like the idea that
a very small orifice becoming fouled could lead to a valve staying open.
But the initial dives convinced me that bi-directional control is a good
idea for a completely different reason. If you use the bleed approach to
close the valves, they close slowly. When diving a K boat, and probably
most subs, you'll often find either the bow or the stern is settling a
little faster and getting you out of trim. The remedy is to temporarily
shut one MBT valve while the other remains open. In Shackleton's recent
tests it was the exact same process, just faster. I found myself closing a
valve for a couple of seconds and then reopening it once back on level
trim. It was very easy to do because the valves had immediate response
times, but latency would have made it much harder to pilot.

I love the simplicity of your design  - wish I hadn't spent all that time
building valves from scratch!

: )

Alec

On Thu, Dec 20, 2018 at 7:24 AM hank pronk via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Alec, thanks for the inspiration.  Watching your sub sink is just friggin
> amazing.  The air cylinders are double acting and will be spring loaded to
> stay closed.  The air pressure will open them with a permanent air leak via
> a tiny drilled hole like you have.
> Hank
>
> On Thursday, December 20, 2018, 5:09:56 AM MST, Alec Smyth via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> Now that is clever, I never thought of moving the whole valve instead of
> just a lid, and it sure simplifies things! Are those actuators NC though,
> or can they be made so? Just so you don’t need HP in order to stay on the
> surface.
>
> Thanks,
> Alec
>
>
> > On Dec 19, 2018, at 8:02 PM, hank pronk via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
> >
> >
> >
> > <IMG_0249.jpg>
> >
> >
> > Sent from my iPhone
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