Re: [PSUBS-MAILIST] Penetrators

["Dan H." <machine@epix.net>]

John,
I like the idea of the threaded rod incased in epoxy, also the thread groves
inside on the tube that contains them.  It sounds sturdy enough to hold water
pressure.  The part that I'm not sure of is having it go directly from the
battery pod to the hull.  Having the cable gives you some extra blowout
protection in case of a battery explosion.  The explosion would blow off the end
of the pod but, it's not the water coming in to the pod that bothers me.  It's
the force of the explosion blowing through the cable connection that I'm
concerned about.
Maybe all my concern is for nothing if the force from the explosion is like a
depth charge going off and deforms the hull into failure anyway.  The depth it
happens at is a factor there.

That's my only concern with a straight connection.  It sure would be easier and
cheaper to do it your way though.   I know some K-350s just use one of the vent
tubes and that's that, but my K-350 plans call for a cable.  I don't know the
exact reason.    Do Ya think I'm over doing the precaution?

One last comment.  You might consider using brass threaded rod for your
conductors.
Dan H.

John Farrington wrote:

> Dan & Vance,
>
> Here are some thoughts on what I think we're going to do with our battery
> cables.
>
> There are 2 battery vents from each pod going into the sub, as you know.
>
> We're going to add a third one, and use it for our electrical thru-hull
> for the pods.
>
> This third pipe is going to be built similar to an electrical thru-hull
> design that Phil talked about.
>
> You basically take a pipe, put grooves on the inside of it, then put a couple
> of appropriately sized threaded rods going through it, spaced out evenly.
> You then fill then entire pipe with epoxy and let it harden.  Next, you
> bolt your battery cables to the threaded rods inside the pod, and also on
> the other end of the threaded rod inside the sub.  (The threaded rods serve
> as your electrical conduit.
>
> We are building our battery thru-hulls as a rigid pipe welded to both the
> battery pod and the sub, built strong enough to withstand the external
> water pressure assuming that we have a horrible water leak into a battery
> pod.
>
> Our thinking is that we treat it as a pressure boundary even though 99.9%
> of the time the will be no pressure differential on it.
>
> We are probably going to put the electrical thru-hulls in place of the
> rear battery pod vents, and move the rear pod vents forward in front of the
> next rib.  Just about 10 inches forward or so, still keeping a fair
> distance between the pod vents.
>
> We still have some small details to work out but please don't hesitate to
> offer any criticisms on this, as we're getting close to cutting the holes!
>
> -John and Monica