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From: Tim McFeely
Newsgroups: sci.military.naval
Subject: Re: Advantages/disadvantages re: mounting of diveplanes
Date: 15 Dec 1995 00:23:31 GMT

>  I was on a diesel boat (Gudgeon ss567) and I remember how hard it was to
>  get into and work around the masts and antennas in the sail. I assume that
>  having bow planes up there would make it even worse. And where you can't
>  get to easy, proper maintenance is rarely done. And we all know poor
>  maintenance on things penetrating the hull is BAD.........VERY BAD....
>  And what about weight considerations. I assume that the sail must be
>  heavily strengthened with doubler plates and structure in order to handle
>  the kind of stresses from sail planes. How does this affect the boat?
>  Oh yeah, and lets see the U.S. went to bow planes and the French went to
>  sail planes on their last boats.......obviously these 2 navies don't
>  agree.
>  Regards, Guy 
>  Tim, this one's for you\/
>  (replacing the bandaids on my knuckles)
>  (cleaning the smudges up off the floor)
>  (god I hate it when my knuckles drag like that)

I guess I have two takes on this:

Fairwater Planes:

1. Finer depth control than bow planes at slow speeds.

2. More noise when the planes slap during rough PD evolutions,
particularly when they are at full dive trying to get the damn boat
down as has been indicated by a boomer sailor earlier in this thread.

3. Less impact on the Center of Gravity, therefore less ability to
affect ships angle of attack. Minimal affect on the VLS boats with full
VLS tubes.

4. Virtually worthless at high speeds. In fact a 688 class can still
maintain some semblance of depth control even after a catastrophic
failure with the fairwater planes at full dive/rise at any speed.
Unable to singly recover from a catastrophic failure of the stern

5. Already crowded sail space has one more intrusion with hydraulic
actuator and linkage necessary to move fairwater planes. More
strengthening is not necessarily needed because of the ice-hard sails.

Bow Planes:

1. Mediocre control at PD. However just like high speed ops lockouts on
the stern plane and rudder during > than 20 knot operations, you can
put a PD lockout on the bowplanes to limit movement at periscope depth
and make it easier for the Helmsman to keep it on depth. There does
need to be a _crisis button_ which would allow the Diving Officer or
the Helmsman to switch it off during Emergency Deep situations

2. Quieter at PD as long as the bow is submerged.

3. Greatest impact on the Center of Gravity. Necessary to recover from
some manuevers or depth excursions (within the safety margins) in VLS

4. Allows more flexibility in manuevering, but a catastrophic failure
in the full dive position requires an immediate emergency blow. May be
able to recover from a catastrophic failure of the stern planes.

5. Removes hardware from crowded sail and puts it in crowded Combat
Systems Spaces, MBTs, and again back close to the hull arrays (although
they ain't the primary sensors anymore). More strengthening is needed
around the hull at the hull penetrations to accept the pounding and
stress on the bow planes.

Looks like most items seem to favor the bow planes. You take your pick,
I was just adding my take on the situation. My preference is... well it
is... classified, no its... damned if I know.

Scope's under...
Tim McFeely
ex-TM2(SS)...a dying breed

From: Tim McFeely
Newsgroups: sci.military.naval
Subject: Re: mounting of bow planes/fairwater planes
Date: 18 Dec 1995 15:34:00 GMT
Lines: 43

Paul J. Adam wrote:
>When I worked on the bow planes for the Batch 2 Trafalgars, one design
>requirement was to be able to recover from worst-case jammed stern
>planes, at maximum depth and speed... to be able to keep the boat from
>going below crush depth. It can be done, but it's a lot of work... 

That is always a system requirement. You have to be able to recover from
any worst case failure in planes/rudder at any depth/speed. Which is why 
the move to bow planes was necessary in the 751+ 688 class boats. There 
was no way the fairwater planes could even begin to recover from a stern 
planes failure in the full dive position with full VLS tubes in the bow. Not 
that they could in any previous class boats, VLS or not anyway.

For the uninformed, the recovery methods for a catastrophic stern plane
failure i.e. Jam Dive, vary slightly with class, but all require the
bow of the vessel to have an upward vector through either planing
surfaces or additional bouyance.  To achieve an upward vector through
the use of planing surfaces there must be enough water flow over the
bow planes to force the bow up. Fairwater planes have limited effect
(virtually none at high speed) on the bow of the boat and there for
require additional assistance in recovery methods, such as Back
Emergency to slow the rate of descent and actually force water over the
stern planes in the opposite direction and push the stern down, plus an
Emergency Blow, forward group first to get the bow up and then the
after group to keep the damn boat on the surface once you get there.

EMBT blows are not something to be considered lightly. Several thousand
tons of submarine hurtling upwards can play hell with anything in the
way. It probably is not acceptable to blow and go into the keel of the
Russian CVBG you are trailing around, nor into the bilge of a VLCC. The
best bet is to recover from the casualty without resorting to extreme
measures such as the Chief of the Watch yanking up on the "chicken
switches" and blowing 4500 psi air into the MBTs.

Also once you do get to the surface, you ain't guaranteed to stay
there. Depending on speed, amount of water volume still in the MBTs,
and overall variable ballast load, you might find yourself headed right
back down. Scary ride, let me tell you!!!

Scope's under...
Tim McFeely
ex-TM2(SS)...a dying breed and not a fan of uncontrolled depth excursions

From: Tim McFeely
Newsgroups: sci.military.naval
Subject: Re: mounting of bow planes/fairwater planes
Date: 19 Dec 1995 14:04:22 GMT
Lines: 40

Arved H. Sandstro"m pointed out the acronymical problems:

>Not being a sub-guy, I did a double-take at first, since MBT is an
>acronym more commonly assigned to another military system. But then I
>twigged to the ballast reference. Nevertheless, the original post
>probably holds true for the other system I was thinking of :)
>Arved H. Sandstro"m                       |     YISDER ZOMENIMOR
>Physical Oceanography Group               |     ORZIZZAZIZ
>Dept.of Physics, Memorial Univ. of NFLD   |     ZANZERIZ
>            |     ORZIZ

Yeah, sorry. MBT stands for Main Ballast Tank. And as Greg suggested it
is possible to "spill" the air out of them, because of the open grate
system vice the closed valve system on the bottom of the tanks. It
would really suck to have to blow and the damn valves on the bottom of
the MBTs not open, therefore the aforementioned open grates. One less
thing to shit the bed in a time of crisis. On USTAFISH we were doing
some testing on a highly bullshit, err classified system that required
us to perform some radical evolutions including several that violated
the safe operating envelope. The third or fourth pass was a jam dive
simulation from a FLANK BELL running at 150 feet (noisy as hell and
apparently the range vessel could see a bow wave on the surface).  The
planesman had to hold the sternplanes in the full dive position for 10
seconds before the Ship Control party could intiate jam dive recovery
procedures. What a ride!!! 52 degree down angle, 45 degree starboard
roll, unheard of on a nuke boat (Diesel boats have done greater up
angles). The gyro crapped out, the plant damn near died, every plate in
the galley broke, the FTOW ended up in CSES as his bench seat flew out
of the track and the he sailed right through sonar into CCC, and the
AEF ended up with 20+ stiches as a 4 lb piece of shipyard scrap came
flying out of the overhead in control and cold cocked him in the head.
I just stood on the front of the Weapons Launch Console and hoped like
hell the lashing straps keep the Mk 48s where they were supposed to be!!

Scope's under...
Tim McFeely
ex-TM2(SS)...a dying breed

From: Tim McFeely
Newsgroups: sci.military.naval
Subject: Re: mounting of bow planes/fairwater planes
Date: 19 Dec 1995 14:05:04 GMT
Lines: 50

Greg Herlein originally wrote:

>Getting to the surface is even an issue, depending on things like how
>much "roll" the ship got during the ride up.  It would suck to spill the air
>out of the MBTs...  
>I always wondered just how well the EMBT system would work
>under crappy real-world conditions (like flooding from a MSW hull valve at
>depth, when the rising angle on the boat fills shaft alley like a glass
>at the faucet... pulling the ass end straight down)  - just wondering, mind
>you.  I tried not to think about those things too hard when I was in - 
>concentrated on immediate actions and casualty recovery stuff, and tried
>to hope the designeing engineers were *really* smart.  I'm glad I never 
>had  to test their designs, let me tell you...  though I can say that the
>various ways to dump the hydraulic system pressure all work very well.
>Damn stuff is scary when it's spraying at you.

Don't know, Greg about the hydraulics. Definite fire hazard with
atomized hydraulic fluid blowing every where at 3000 psi. Sure as hell
messy, but it wasn't something that bothered me, much. Course all
things are relative, says one who spent his watches in close proximity
to 7-8 tons of PBXN and well over a thousand gallons of monopropellant.
I used to get scared to death of the 4500/2000 psi HP air reducers for
the Torpedo Ejection Pump. Setting the things always bothered me and if
you lifted the relief you couldn't hear for several days. The other
thing was the actual Ejection Pump itself. I always wondered what would
happen if the damn ram decided not to stop at the end of its stroke
and just continued through 21 man berthing or the log room and lower
level head (depending on which side) into AMR. I always hoped it would
stop before it punctured a hole in the diesel fuel tank/reactor
shielding. It was also the only casualty (internal) that I can think of
that would instantly cause flooding, 2000 psi hp air leak, 3000 psi
hydraulic leak, 400 psi lp air leak, 150 psi lp air leak, (not slow
leaks either, but full blown dumping of the systems) potential
rupturing of the Trim and Drain system piping, and if the port side ram
carried away it could potentially (after trashing the scrubbers) pierce
the heart of the O2 generator.

Scope's under...
Tim McFeely
ex-TM2(SS)...a dying breed and thinking happy thoughts today in CIVLANT

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