[PSUBS-MAILIST] report on: half finished k250 hybrid on ebay

[Ian Roxborough <irox@ix.netcom.com>]

Hi,

first off, thanks for all the help in research guys, you're a big help.
Second, all this is based on what I've learned from books, the mailing
list and the psubs convention (in case you're going to buy it based on
what I've said - this was my first time touching a ksub).

Third, it's a long-ish report, if you just want to look at some pictures,
I've put some up on the moki picture exchange:
 http://www.prismnet.com/~moki/subfiles.html

Ebay link:
 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7115644553

First attempt to sell it for $80k:
 http://www.watercraft.gs/listing.php?main=Submersibles&sub=Submarines
 http://www.watercraft.gs/uploads/adphotos/a30p1553012798orig.jpg


Yesterday I visited the K250 hybrid sub that has been on ebay for the
last few days.  Here are my finding.

Viewports:
As Dan said, the viewport housing are a little thin, with around half an
inch metal to glass contact surface.  The 16 inch main viewport also has
half an inch of metal to glass load bearing surface.  However, after
reading the K250 plans that where provided with the vessel, the plans only
call for half an inch.  I think this might be the main reason the Captain
Kittredge is no longer willing to sell K250 plans.  The smaller 8 inch
viewport housing look like they where designed from looking at the specs
of the main view port.  If you are satisfied with K250 safety record, then
you're probably not going to worry about the smaller viewports, the main
one has a far smaller inside to outside diameter ratio.

ABS viewport specs (based on Dr Jerry Stachiw's work) calls for a
inside to outside diameter ratio of 1.25 to 1.5.  The main view port
has a ratio of 1.07.  The small viewports have a ratio of 1.14.

In the two viewport housings that have been placed on the main cyclinder
I noticed a strange groove on the inside vertical wall around the base.
At first this seemed like the viewport housing had been welding on the
presure vessel in two parts and the groove was a gap.  Although now I
think that they where welded into place as one piece and became warped,
then the builder tried to use some tools to correct this and caused the
grooves.  No way could these before an O-ring, they followed an
eliptical path (deeper at the top and bottom).  Under pressure when the
hull starts to 'shrink' in, it will put pressure right on this groove.
Those would have to be replaced.  The similar viewports in the conning
tower didn't have this groove.


Ballast tanks:
The original builder tried to implement some sort of trim tank system.
With the ksubs being designed as level keel divers, I'm not sure if this
would have been very effective.  The trim tanks are really just VBTs,
one in the bow MBT and one in the stern MBT.  There is a hard pipe
connecting the fore and aft VBTs so some water could be transfered.
This pipe ran through the inside of the pressure-hull with many fittings
and joins.  Nice idea, but it makes me kind of nervous, also not sure of
it's effectiveness.  Maybe if the hard pipe ran on outside it would be
better.  The MBTs had covers bolted onto the bottom with 3 fist sized
holes to let the water out.  I didn't  like the metal MBT tanks welded
on to the endcaps, but that's more of person preference for leaving it
open to more customization in the future (without cutting it up everytime
I want to change something).


Weldings:
The weld attaching the conning tower gusset to the main cylinder was
ground concave (like Gene said).  This would have to be cut off and
welded back on.  The endcaps looked ok on the outside, althought the
weld had been ground down.  The inside of the end cap welds looked ok,
althought in one part, possible as start/finish weld beed point, there
was a small gap.  Without the paint, I might have been able to stick my
finger nail in deep enough to go below the metal being joined!  Some
if not all of the endcap welds would have to be replaced.


Thru-hulls:
Some of the thru hulls where interesting.  They 8 some holes and one
larger hole.  Each hole that was not in use had a grub screw plugging
it.  This seemed pretty neet, need a new thru-hull, just remove a grub
screw.  Not sure if this is a standard K250 (I didn't see any drawings
for it in the plans), but seemed like it would work well.  Adds a bit
of flexability for future expansions (although some what size limited,
I think less than half an inch).  I didn't see any flood valves,
although it probably won't be too hard to loosen some hoses and left
water in.   I'm not sure about the plastic hydrolic hosing that are
used to plum the MTBs and VBTs.  It said it was rated to 300psi, but
if one of those was to get rubbed on something after a few uses, I'm
not sure how much pressure it would hold (also not sure if the plastic
hoses where part of the K250 plans or not).

The internal battery box takes up too much internal space, I doubt
two normal people could fit in there unless the battery box was removed.
Putting two K350 style battery pods on would be the way to go.

It had the drop wieght system complete and lead (400lbs?) in the tray.

I liked the wooden deck, nice touch, easy to walk on.

I can't find any where that K350 plans where followed.  As for the
K250/K350, this is a K250 hybrid with a some aspects styled after the
K350, nothing more.  Maybe test it to 400feet and operate it to
150 to 200feet.

Issues I could identify:
 - end-caps need welds corrected (or rewelded).
 - conning tower gusset needs rewelded.
 - small viewports on main hull need replaced.
 - interal battery box to be replaced with external pods.
 - remove built in trailer bits.

Most of all, I'm not sure if the builder re-calculated the weight,
displacement and bouyancy after making all these changes.  That would
have to be done before making any further changes.

In conclusion, I would buy this, but it isn't worth $8000 to me.  It
seems to be worth $11400 to somebody, I hope they know they are not
buying Lake Diver.  The people selling it don't really know about ebay
or the internet or the Lake Diver photos, a friend put it on ebay for
them and grabbed photos 'off the internet'.  They don't even know when
the auction ends.  In the end I told them to call me if they can't find
a buyer and I would take it off there hands.  If anybody wants this sub,
please don't hold back for my sake.

Thanks,
  Ian.
(Wish I was writting long reports on diving subs rather than examining them.)



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