RE: [PSUBS-MAILIST] Penetrators

[Alec Smyth <Asmyth@changepoint.com>]

Guys, I'm not sure how many amps a K-350 needs,  but we might be in the same
ballpark since I'm also using a pair of trolling motors. I researched
commercial bulkhead connectors and settled on this one which at 4 conductors
x 50 amps each I think is ideal:
http://www.subconn.com/subconn.asp?page=pow04&pic=img2f. I like this
connector because it deals with both battery pods using just one hole in the
hull, minimizing failure points. Of course this takes care only of the hull
side, and you'll still need a penetrator per battery pod. The cost was about
three hundred odd bucks for the male-female pair - not cheap but not
impossible either.

Something I still have to figure out is the wiring for my ruddervator
actuators, which will be outside the hull. They need 3 conductors each, two
of which should handle 6 amps. I'll probably bring these through the
pressure hull using some Subconn penetrator since its a high pressure
boundary. But once outside, the cables go to the two actuators, which are
pressure compensated. Its probably not worthwhile buying expensive
penetrators for that last low-pressure boundary. If I go with the home-made
technique of threaded rod, etc., what d'you do about connecting the threaded
rods to the cable? Just massive amounts of silicone sealant or something?
There must be something a bit better. Suggestions are very welcome!

thanks,

- Alec

-----Original Message-----
From: Dan H. [mailto:machine@epix.net]
Sent: Friday, January 18, 2002 8:13 AM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Penetrators


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