Naval Submarine Medical Research Laboratory

NSMRL REPORT 1205 27 MAY 1997

A BIOMEDICAL REVIEW

OF

THE U.S. NAVY SUBMARINE ESCAPE SYSTEM:

1996

Steven J. Frank, LT, USN

Michael D. Curley, CAPT, MSC, USN

Steven J. Ryder, SURG CDR, RN

Released by

R. G. Walter, CAPT, DC, USN

Commanding Officer

Naval Submarine Medical Research Laboratory

19980810 150

Approved for public release; distribution unlimited

[DTIC QUALITY I2JBHJCIBD 1 f\(X u^V-IO-^K»
A BIOMEDICAL REVIEW

OF

THE U.S. NAVY SUBMARINE ESCAPE SYSTEM:

1996

by

Steven J. Frank, LT, USN

USS BATFISH (SSN-681),

Michael D. Curley, CAPT, MSC, USN, and Steven J. Ryder, SURG CDR, RN,

Naval Submarine Medical Research Laboratory

NSMRL REPORT #1205

Naval Medical Research and Development Command

Research Work Unit 63713N M0099.01A-5201

Approved and Released by

R. G. WALTER, CAPT, DC, USN

Commanding Officer

NavSubMedRschLab

Approved for public release; distribution unlimited
SUMMARY PAGE

THE PROBLEM

~uszzrbarotrauma'

and d

- -^r^^^^

Zeil' SZt^eT 6SCaPe SyStem CaPabÜ"

ty

» '"">'** «-» potential

THE FINDINGS

Present U.S. Navy submarine escape procedures and equipment are

inadequate to provtde reasonable assurance of escaper survival. iTck ofThermal

protection for the escaper, complex manual escape trunk proceduresandslow

compress of the escape trunk, with resulting exposure^^Sprllres

of nitrogen and carbon dioxide, are major obstacles to successful escape

Kecommendarions mclude replacing the Steinke Hood with commercially available

equrpment that provides adequate thermal protection, automata USSlavy

:t~SäTintroducmg reaHstic'"•"*-^

APPLICATION

submaJ^es6^"^ apply t0 aU CUrrent and future classes of U.S. Navy

ADMINISTRATIVE INFORMATION

This research was carried out under Naval Medical Research and Development

Command Work Unit 63713NM0099 01A wm ««^K ,, •

iU^v

eiopment nrnhlpm« » TU* „• iviuuyy.uiA-o^Ul, Submarine related decompression

reflect?^ I 7T 6XPreSSed m^

rep0rt are th°Se of the authors and do not

D^ff ns or £uslw ^Trf*" Department °

f

^ Navy, Department of

rf £f\ ! Government. It was approved for publication on 27 May 1997

and has been designated as NSMRL Report # 1205. '

n
Abstract

The current method of escape from United States Navy submarines, the buoyant ascent

using the Steinke Hood, was introduced in 1962. Pressurized buoyant ascent training ceased in the

United States in the 1970s due to concerns associated with financial costs and health risks Operating procedures for escaping from U.S. Navy submarines have remained essentially unchanged

since World War II. In 1974, Neuman highlighted significant biomedical shortcomings in the escape system: hypothermia, nitrogen narcosis, hypercarbia, barotrauma, and decompression

sickness. He attributed these shortcomings to the method of escape and operating procedures

Furthermore, as this review suggests, the current method ofsubmarine escape is no longer

practical, because the Steinke Hood provides no thermal protection for the escaper during the

escape and while awaiting recovery. Accordingly, citing emerging technology and recent studies

this paper presents biomedical-based recommendations for enhancing survival of escapers by a) '

overhauling current submarine escape systems and procedures and b) substituting existing thermal

protection suits for the Steinke Hood.

Key Words: submarine, escape, rescue, Steinke Hood, medicine, biomedical, SEIE, review

in
TABLE OF CONTENTS

Summary Page Page

ii

Abstract

iii

Objective

1

Introduction

1

Discussion

2

Risks in training for submarine escape (Training issue) ~

Major problems with USN submarine escape practice (effectiveness issues) .".'.'.'.'.'.'.'.'.' 3

Summary

11

Recommendations .

14

References ...

15

Acknowledgements.

17

LIST OF TABLES

Table 1. Global water temperature in °F at surface and 600 fsw (183 msw) 7

Table 2. Predicted survival times for exposure water temperatures n

Table 3. Bottom time limits for U.S. Navy no-decompression air dives 12

IV
OBJECTIVE

IT • ,i J

Pl!70Se PapCr iS t0 GXpand and COnflrm critical assessment ofthe current United States Navy (USN) submarine escape system from a biomedical perspective and to

recommend means ofimprovement accordingly. This paper will not address the advantages

and/or disadvantages of escape versus rescue from a disabled or distressed submarine.

INTRODUCTION

A J

l0*?!isubmariMS a* designed, built, and operated to the highest possible safety

standards. While accidents resulting in a submerged disabled submarine (DISSUB) are rare

they have occurred, and the USN should be highly prepared to deal with such an occurrence'

There are two means ofsaving life following a DISSUB. The first, escape, occurs when

survivors exit the submarine via a hatch and make an ascent to the surface, and the second

rescue, occurs when survivors are removed from the submarine by a submersible, e g a deep

submergence rescue vehicle (DSRV) or Submarine Rescue Chamber (SRC).

During the past three decades, the USN has concentrated its' research, development and

operational resources on developing submarine rescue as the principal means ofsaving lives

following the sinking of a submarine. The USN spends approximately fifteen million dollars a

year in upgrading and maintaining a DSRV program in the event that a DISSUB rescue is

required As a result ofthe USN focus on rescue, the current method ofsubmarine escape using

the Stemke Hood remains essentially unchanged since the 1960s.

Though rescue is the preferred method ofsaving life, it is essential to have an effective

escape system because survivors may be forced to conduct an escape before rescue forces arrive

on site. Operational conditions and engineering difficulties may prevent successful transfer of

survivors from the DISSUB to the rescue vehicle. Furthermore, logistical considerations may

impose a delay ofup to five days in the transport ofthe DSRV to the DISSUB and environmental conditions in the DISSUB may deteriorate as a result offire, flooding, hypoxia, rising

CO and pressure, to the extent that an escape is imperative for crew survival. For example on

26 August 1988 the B.A.P. PACOCHA (former USS ATULE, SS-403, transferred to Pern in

1974) sunk to a keel depth of 140 feet ofseawater (fsw) (43 msw) in 5 min as a result of a

col isiondunng a surface transit to its home port. The United States fly-away McCann rescue

Sy^emi!'e

;f^WaS aCtiVat6d'

bUt ab0rted in transit when deterioration ofthe atmosphere

within the PACOCHA led to the decision to use buoyant escape techniques (1). Therefore

efforts to improve the current methods ofsubmarine escape should be further developed. '

th„ «t Tl^

eSCTaViable md reaIistic °Pti0* for the USN, this paper proposes replacing

the Stemke Hood with advanced thermal protection suits (e.g., the British Mk 10 Submarine

Escape and Immersion Equipment [SHE]) on USN submarines as soon as possible, modifying

outing USN submarine escape trunks to accommodate a more automated system similar to that

used by the Royal Navy, and incorporating automated systems into design ofthe New Attack
5KJStSÄssa=rÄ55a»=2ar»

DISCUSSION

äZSe PeTTW3S "*> C0S,Iy in tams of»»

d

»«Wal aXouldT

Due to the significance ofDr. Neuman's thesis and in fight ofrecent studies anH emergtngtechnology, ^

paperwal severa, ions «£ ^^^»d

Sit! manne eSff

SyStem

-

0fDr'Neum»'s ^en assumptions Lpaper

Risks in trainingforsubmarine escape (Training issue)

27tolaZ "

b

h

U

r

SigniJ!C

T

m0rbmty andm0rtaHt

y

aSSOciated *** tower training due to an air embolism which is notjustified. (Neuman, p. 12)

In the training tower, the escape trainees did not operate the escaoe trunk and H.H t

IZ^cllft f

PCr yeaf-fd SpendiDS m0re^200'000 dollars a

yearTn a

psychological test ofunproven validity and reliability to weed out 3% ofthe failures while

Dr. Neuman reported that in 1973, 3,405 men ascended mom the U S Navy escaoe tower

~"ZöSLondon' M

t0,al °mi (13%)

program. 300 ofthe 442 were unable to withstand the pressure

* «"—<* testins while«Sthe final SL,

n,? ?

H

°

0d m 5

•

6 fsw' Th^fi^e, 14 out of3,405 men (0 41%) were screened

ou, ofthe snbmarme pmgram due to their inability to conduct the escape tow t (
We concur with Dr. Neuman's opinion that the use ofpressurized submarine escape

framing primarily as a psychological screening tool for submarine service is ina^ropriatTdue to

lack ofscientific or other evidence that validates its use in this way. Moreover given*Native

success of alternative, less expensive screening methods that have been in placefin eZS

i*are~^reinstitution ofpressurized taining soiei^

f

°

r

psychoiogicafrc~

The experience ofother navies conducting ascent training in preparation for actual escape

S

TTe- \

a

f

dy °fthC JapanCSe MaritÜne Self-Defense Force traming, Ikeda and Oiwa

reported no embohc accidents in 14,798 conventional Steinke Hood ascents from a depth of

approximately 33 fsw (10 msw) (3). The Japanese use mechanical means to control the rate of

Smffron^O ntf,nR°fyal,o aVy,

(

T

CUrTently C

°

ndUCtS **** UsinSbuo^—ts w h SEE from 30 and 60 fsw (9 and 18 msw), and hooded ascents from 100 fsw. Prior to 1975

SSL ^ol^no^f aSCentfr°

m 10°f8W(3

°

msw>- *1994>Bentonetal.Reported

nJTr\ 54 ?

d 1993 there Were 5 deaths in 277'147 ascents'a ra* of 1 per 55,429 (4) Ofthe 5 deaths cited m the report, all occurred prior to 1975. An additional fatality in RN escape

training occurred in 1995 from a gas embolism following a 100-fsw hooded ascenf FoT

pulmonary barotrauma and neurological decompression sickness (DCS) associated with RN

escape traming, the most hazardous current profile was the 60-fsw buoyant ascent which

displayed an mcident rate of 0.45/1000 ascents.

m^nH%uCQ

nM0rreSPOndenCe'Dr NeUman re

-

affirmS Ws convi<*ion that because the present method ofU.S. Navy escape provides little likelihood of affording safe submarine escape, there

is negligible benefit to tower training even ifthe risk associated with tower training is small (5).

Majorproblems with USNsubmarine escapepractice (effectiveness issues)

Compression

(I) A compression time oftwenty seconds to 600feet indicates the maximum possible'

escape depth. (Neuman, p. 6)

The "maximum possible" escape depth is currently greater than 600 fsw (183 msw)

*Z ?

deCadeS'±e British COntinued imPr

°vement ofsubmarine escape by using

fa Jruri dem

l

onstrated ±at raPid compression in 20 s to 625 fsw (190 msw) is achievable

6), and that the technique ofhooded escape is practical in both sea tests to depths of 600 fsw

(183 msw), and m laboratory tests to a simulated depth of 625 fsw (190 msw) (7) From

additional studies using goat trials, the RN concluded with reasonable confidence that safe

Z71ZT fTot?01117?

0 fSW (228 mSW) (8)

-

fc addition'escaPes from d

<*ths of 900 and 950 fsw (274 and 289 msw) may be possible with a majority of crew surviving however the

authors also note that there would certainly be casualties requiring urgent recompression '

Unfortunately, empirical data to estimate the incidence and severity ofhuman DCS from such

great depths are lacking.
Current equipment on board USN submarines is unable to conduct the extremely rapid

pressunzation executed by the RN in their automated trials. extremely rapid

(II) It is exceedingly unlikely that an individual who has never been trained in high speed

compression mil be able to compress to 600fsw in twenty seconds. (Neuman, P7)

U S N,w! ^

SUmpti°n is Plausil;le from aUS

-

Nav

y Perspective, given the 1974 and current

U.S. Navy submarine escape trunk operating procedures. These procedures require the e^per

to manually control compression by performing multiple steps (9). However operation of an

escape system similar to the British Hood Inflation System (HIS) requires nriSÄ"

^racticarS } Y*" "***"^^ *

Wgh Speed Session procedure

Furthermore there appear to be no physiological reasons why high speed compression

n^°sunr

CCThShed

-

DUring a StUdy °f2

°

V

°

lunteerS COnductinS 1 l^sLlatedTapes from sunken submarines in a pressure chamber at the Royal Naval Physiological Laboratory the

cl.Tt tT°

btamed: °,CaSeS °f emb°lism 4 DCS'a few case* of«nid itcKd?

SSL £J 7fTSfr- °Tf^

latter reSUlting *a

P

erforated »*P«** membrane (f

2SS mdl!;duals,

had never been tnuned in high speed compression and they were able to

withstand the rapid compression with minor complications that would not have affected their

abihty to contmue with the submarine escape.

M«* «

ffiSh SPe!td comPression rates m desirable because they shorten the exposure time to

ttZTrTTn- ^compressionresults in less nitrogen absorbed into tissue and,

correspondingly, the risk ofsubsequent DCS is reduced. The British system allows rapid

pressunzation by flooding directly from the sea, while the USN system is pressurized using air

Air is more compressible and, therefore, compression is slower than whenusing sea wateT

Further m the Britishi system compression begins when the water reaches the level ofthe vent

dram, thus reducmg the air space to be pressurized and significantly accelerating compression.

(Ill) Nitrogen, at a partialpressure equivalent to 600feet, will render an individual

completely disoriented ifnot unconscious in seconds. (Neuman, p. 7)

Nitrogen narcosis is experienced at 600 fsw (183 msw) following a 20-second rapid

Z

PreST ft3

Tu°nd b0tt0m ^

e

Phys^al effects ofnitrogen at higSpLure

vary with the depth ofthe escaper and the time the escaper remains at that depth A rfpid

automated system minimizes the potential deleterious effects ofinert gas narcosis on escaper

o^Tflwas7^^^^conducted * Elated depths of 500, 550, 600, and

rate ofJJnt'Z?\\ ' n*^^*

2

°"SeC°

nd comPression> 3-second bottom time, and a

rate of ascent of 8.5 fsw (2.6 msw) per second. The results ofthe study were that no sub ect felt

any untoward effect ofnitrogen narcosis during this rapid cycle (8). How long tiie subject

wouWremamun^pafredbeyondSseimerbysubje^

known, but continued use of a complex, nonautomated system encourages slower compression,
longer bottom time, and potential rise of behavioral impairment due to narcosis. As discussed

further below, under ideal conditions using the current USN system, 71 s are (theoretically)

required to flood the trunk, effect compression, and exit the trunk from a depth of 600 fsw (183

msw). Nitrogen narcosis may impair performance under these conditions.

(IV) Carbon dioxide toxicity (hypercapnia) wouldprobably represent the depth limiting

(a) Fleet Ballistic Missile submarines' carbon dioxide levels are usually between

l.U-1.5/o.

(b) Between six & seven atmospheres, incapacitation would occur.

(c) Immediate unconsciousness occurs in an atmosphere of10% carbon dioxide

(d) LTNeuman cites as supporting documentation: "The maximum realistic depth

ofourpresent equipment is probably closer to 100feet rather than 600feet, and

the limitingfactor is carbon dioxide toxicity, not decompression sickness.

(McMillan) (Neuman, pgs. 7 and 8)

Rapid compression (20 s) with niinimal bottom time (3 sec) minimizes the effects ofCO

toxicity, thus hypercapnia does not represent the depth-limiting factor during escape Current *

average C02 levels ofUSN fast attack nuclear submarines with C02 scrubbers are approximately

4 torr at 1 ata, corresponding to an average level of 0.5% (data were obtained during a 6-month

Mediterranean deployment in 1995). Ballistic missile submarines maintain similar CO, levels

Present USN submarine guidance aims to commence a submarine escape prior to CO, reaching a

dangerously high level, and to complete crew escape before C02 levels reach 6% (9).

Compressing the escape trunk with submarine air at 0.5% C02 to an escape depth of 600

fsw (183 msw) at 19 ata would raise the C02 level to 9.5%. A study on The Physiological

Effects ofHigh Concentrations ofCarbon Dioxide by E. W. Brown (10) presents the following

/n ( .( >2 Time (minutes) to the mtnWpH,» ijmit*

6.0 20.5 - 22.0

7.5 3.5- 6.0

10.4 2.25

12.4 2.0

Note: a. According to the study, none ofthe subjects could have withstood 10% CO, for longer

than 10 mm without complete stupefication (10). *The intolerable limit is the time that collapse

ofthe subjects would have resulted in approximately one minute.

b. It is possible that the average C02 concentrations reported above for USN submarines

may be higher in the DISSUB situation ifC02 scrubbing capability was reduced.
(V) Operating an escape trunk is absurd under the "best circumstances"

(a) 39 F water

(b) Atmosphere containing 5-10% carbon dioxide

(c) Anesthetic levels ofnitrogen (Neuman, p. 9)

This assumption by Dr. Neuman omits reference to time, a critical factor to the viabilitv

of any escape procedure. A survey ofthe world's ocean temperatures in hl^o al ove the *

four seasons reveals a wide range oftemperatures from 1,000 fsw (3ol2l)T£Zl^TUs

paper concurs with Dr. Neuman's working figure of 39°F (3 9°n fhr wTtZt I

;stfer ITT:fsw (i83 msw) *eff:c"oftsfh SdLrsrt^over

*7"»Ste'?°Hood; *" UnCertain*

ata

«h ^»Pieced escaperwill beTle ,o

perform the required series of escape trunk actions while immersed in 39°F O 9°C) water A,

XKÄ.T6S dem°

nStrated ""' "^ »P-io„, followed b^mma! «^Zl^Z^r eSCaPe' Wl11 C,rCUmVent^

ProWemS *"**o.

1!? S"

bmJ"iners

, mus,f^"" inhospitable environment ifescape ispossible- Seventy

^fP^l'^ersion in 39 Vwater and ■■championsJnnters" were noToTgt able to stay afloat. (Neuman, p. 9) tunger

submarin^1*

6

T* ^ "^°

f

^^ pr°

tection «* **> ^als during

hypXntiaXtT*-"^* """"^ ^^^**individuaI effects <* hypothermia and cold water immersion. The first interval encompasses the time the escaner is

exposed to seawater from flooding ofthe escape trunk until reaching the surfte TteszZd

interval encompasses the time the escaper is exposed on the surface until he is recovered

(A) Reaching the *wrface with n Steinkr tfnnrl

The question surrounding the first interval is whether the escaper can reach the surface

stinketod'Thf.W r

S

Steinke Hood. The most hmitmg V*"*operational

^^

conditions"

^^

are partially ^£ÄÄ defined bv temnerLre

re±Ps 1VTdUring ?

m

°

nthS °fAprfl "* S

^

mb^*«*». Itota,C„P

s Tn^se regions nclude the waters adjacent to Russia, Germany, the former Yugoslavia PanarT the east

and west coasts of Ute United States, China, Britain, Gibraltar, India, Ismel, Libya CMe

«aktat'l2", Tit,W,thiD Ukely SUbmarine 0pOT,inS ~* *» timpemmre po'sh^s were taken at random for the purpose ofdefining the most extreme temperature conditions fSI an

e aper ustng the Stake Hood. The unclassified environmental data were SZSÄTto

Fleet Meteorology Center m Monterey, California. Temperature vs. depth dab, a60017

LinTe HLT^'^""fr011 "" "^ Deco^-°n" '^retieal eLpe d^th usinTtiae Stemke Hood and the successful escape depth using the British Mark VIISEIS The

£^Ä"JS"at 60°

fsw (183 rasw) range fom 32°F <°°c

> <° «•* (»•«•c,
TABLE 1. GLOBAL WATER TEMPERATURE IN °F AT SURFACE AND 600 FSW (183 MSW)

Coordinates (long-lat)

003-24 W/36-06 N

006-00 W/05-00 N

007-30 W/66-30 N

008-00 W/64-30 N

009-30 W/66-30 N

072-01 W/21-46 S

072-18 W/39-12N

081-19 W/11-13N

120-12 W/34-18N

125-36 W/47-06 N

011-24E/42-00N

018-18 E/30-18N

034-12 E/32-30N

132-30 E/36-18N

139-00 E/55-48 N

600fsw (183 msw) (°F)

58.4

37.0

34.9

34.1

33.0

62.3

49.5

63.5

48.6 (520 fsw)

44.9

59.4

62.3

64.0

41.3

32.5 (410 fsw)

Surface (°F)

61.6

37.5

34.2

37.0

34.0

66.0

49.7

81.3

56.3

49.0

61.4

66.0

67.7

54.7

39.0

The total USN escape time from 600 fsw (183 msw) can be divided into three phases- (1)

time to flood the escape trunk, (2) time of compression and exit from the submarine, and (3) time

to reach the surface:

Flooding the escape trunk

Compression and escape

Reach surface

11s

60s

86 s

TOTAL TIME

(1) Time to Flood the Escape Trunk

157 s (2 min 37 s)

The time to flood the escape trunk is based on fully opening a 2.5-inch ball valve at 19

ata (600 fsw) ofpressure and flooding the escape trunk to the "bubble line" (estimated at threequarters ofthe total volume of 132 ft3

or 8,448 lb sea water). We can use this formula to

calculate the time required: (11)
W = CDxkAx/(2gh)

W = rate offlooding (#/s)

CD - coefficient of discharge (1.0) based on the geometric configuration ofthe hole and

flow resistance with the ball valve fully open

k = weight ofseawater (64 #/tf)

g - ££* "" h°

Ie " *" <ta*d

°

n My °PeninS 4e 2

'

5

"

bal1 valve in *« «I* tank)

h = depth in fsw

Escape trunk total volume is 132 ft3or 8,448 lb sea water. The "bubble line" is

approximately 3/4 ofthe total volume or 6,336 lb sea water.

Time to flood the escape trunk at depth in seconds = 6,336 / W

(2) Time ofCompression and Exit from the Submarine

lr °

fC0£PreSSi0n md exit from the escape trunk is based on a 20-second rapid

compression ofthe escaper until he departs from the escape trunk.(12)

(3) Ascent to the Surface

The time to reach the surface is based on an ascent rate of 7 ft/s. (13)

Note that flooding, compression and escape (not including ascentO under oresent USN

mi;;zop^^TI

11 tak\a minimum °f 7i s>versus 2

°

swi"t mr

0

e

^system. Furthermore, these times above are based on escape under ideal conditions ^3ed such that

delay does not occur due to other physiological effects (e.g., hypercapnia, nitrogen narTsis)

Current USN escape procedures are the following:

llZ^^r^***t0** bubble line' *» following

acti°ns are required by the trunk operator to escape per the subamrine ESCAPE BILL:

- When the trunk is flooded to the bubble line SHUT the FLOOD

- Ventilate for 10 s using the trunk BLOW.

- Shut the trunk BLOW.

- Shut the trunk VENT.

- Stand by to inflate the hoods and equalize sea pressure.

a. Each man hold his nose shut through the hood fabric.

b. On the leader's signal take a deep breath and hold it.

c. Inflate the hoods instantly.

d. Open the trunk BLOW rapidly and fully.

e. Start continuous deep breaths while the trunk is being pressurized.
f. Attempt to equalize at each inhalation.

- Equalize the trunk with sea pressure.

a. Keep the water level at the bubble line

b. Adjust the BLOW, VENT, and FLOOD as required

c Check the mechanical latch indicator to ensure the hatch is loose on the

seat.

- Escape hatch, first man.

a. Take a deep breath and hold it.

b. Shut and remove the snorkel from his mouth and unsnap the hood

charging line.

c. Shift to normal breathing.

S^^^^13" °

F PR0CEDURE T

° ^VENT DEPLETION OF

d. Keep the torso as erect as possible while entering the escape chute.

e. Crack the escape hatch to prevent a rush ofwater, allowing the leader to

adjust for bubble line water level.

f. Open the Escape Hatch.

g. Signal all clear.

h. Proceed to the escape hatch,

i. Exhale until comfortable,

j. Release hold on the deck.

k. Breathe normally during the ascent to the surface

1. On the surface shift to snorkel or unzip the hood

m. The second and third man escape in the above manner

"

Th£ ^fT*0 iS the IaSt man in the team> h^ners signals

OUT to the compartment, checks the escape hatch seat is clear

and ascends.

o. Each man in sequence shifts from snorkel to hood breathing

KEEPING THE TORSO ERECT to avoid spilling air out ofthe

hood.

p. When the last man has gone SHUT THE ESCAPE HATCH from the

compartment (9).

dunng a buoyant ascen, escape „sing the Steige Hood in 57°F (M-Q waJZmembeL 0f
the B.A.P. PACOCHA noted that the water flooding the escape trunk was so cold that they were

sure they would die (1). It is problematic whether a thermally unprotected escaper will be able to

perform the required series oftrunk actions shortly after immersion in 39°F (3.9°C) water- we

believe the lack of proficiency by the escape trunk operator combined with the effects of '

hyperventilating m the cold escape trunk will lead to an increased state of confusion and

probable failures of escape.

The British system is simpler to operate, in addition to providing thermal protection The

escaper dons his suit, climbs into the tower, and inserts the inflator connector into the stole

charging valve. He then concentrates on remaining connected to the Hood Inflation System

while his colleagues flood the tower from the escape compartment. When pressures are equal the

upper hatch should open automatically, as its' weight is balanced by a spring. The escaper leaves

the trunk through the hatch, breathing normally from the hood until he reaches the surface From

a depth of 600 fsw (183 msw), the compression and exit phases from the submarine take approximately 20-25 s (6). Escape time in the British system is less affected by sudden exposure to cold

water and toxic gases because the SEIS provides thermal protection and the breathing of

dedicated BIBs air avoids the problem ofbreathing compressed submarine air. British

submariners who escaped from a submarine during a recent Norwegian fjord exercise reported to

the authors that they were not unduly cold in the escape trunk while outfitted in the SEIE.

(B) Surviving on the surface

Ifthe escaper arrives at the surface alive and conscious, the second interval becomes

effective. Death from hypothermia is a major concern on the surface. The best evidence of

individual survival with flotation in cold water comes from studies of casualties offighting ships

during World War II. Through investigation ofnaval casualties involving more than 30 000

naval personnel, two thirds of all fatalities were due to drowning or exposure, and the majority of

these were as a result ofimmersion hypothermia (14).

Molnar (15) concluded from eyewitness accounts by survivors that most people died

within 6h after immersion in water at 59°F (15°C), and within 1 h in water at approximately

32 F (0 C) (15). Additionally, a survey ofU.S. Navy records by Molnar shows that survival is

limited to 10-20 mm in 32°F water (15). Further, sudden immersion in water at 32°F (0°C)

produces a reflex gasp followed by a 1- to 2-minute period of hyperventilation (16), potentially

exacerbating circumstances.

During the rescue ofthe passengers ofthe Titanic, 1,498 out of 2,201 were reported dead

within 2 h after rescuers arrived, even though all ofthe passengers found dead in the water had

life jackets or some flotation device (14). Water temperature was reported to be approximately

39°F. In April 1989 the Soviet submarine Komsomolets sank in the Norwegian Sea Surface

sea temperature was about 38.5°F (3.5°C) and the sea state was 3. Fifty-nine men abandoned

snip on the surface, 28 ofwhom managed to reach a life raft and climb into it. The remainder

stayed m the water, but some clung to the raft. Within 75-80 min a support ship rescued 30

10
survivors (23 from the raft and seven from the water). Twenty-nine perished (5 in the rate and 24

in the water); three ofthose pulled from the water died later that day. The report does not detail

what clothing was being worn at the time of abandonment. Overall mortality for this exposure

was 54%, but mortality ofthose remaining in the water was 87% and those in the raft was 18%

Based on the data in Table 1, year-round surface temperature outside the tropics is about

65 F (16.7°C) and is never much warmer than 59°F (15°C) along the North Atlantic sea routes

Britain, and most ofNorthern Europe and North America. According to Table 2, survival of

individuals immersed for a period of 7 h in water temperature < 70°F (21.PC) is unlikely (18)

From the data in the US Navy Diving Manual, it is anticipated that use ofthe Steinke Hood alone

during escape will lead to death ofsubmariners within 1 hr in 40°F (4.4°C) water due to

hypothermia (19).

TABLE 2. PREDICTED SURVIVAL TIMES FOR EXPOSURE WATER

TEMPERATÜRESKI8) :;f

Water Temperature

oF (oC)

32.5 (0.3)

32.5 to 40.0 (0.3 to 4.4)

40 to 50 (4.4 to 10.0)

50 to 60 (10.0 to 15.6)

60 to 70 (15.6 to 21.1)

70 to 80 (21.1 to 26.7)

80 (>26.7)

Time to Exhaustion or

Unconsiousness

< 15 min.

15-30 min.

30 - 60 min.

1 - 2 hrs.

2 - 4 hrs.

3 -12 hrs.

Indefinite

Survival Time

< 15-45 min.

30 - 90 min.

1 - 3 hrs.

1-6 hrs.

2 - 7 hrs.

3 hrs. - Indefinite

Indefinite

SUMMARY

Once the decision to make an escape has been made, the process must be conducted

rapidly and efficiently to minimize physiological effects during escape and to minimize

complications while awaiting rescue on the surface. In a DISSUB, pressurization ofthe affected

compartment by high pressure air leaks, flooding, emergency air, and/or oxygen bleed will cause

11
ssss^ ThlslsdisPlayed

TABLE3. BOTTOM TIME LIMITS FOR Ü.S.NAVY MO-DECOMPRESSION

. DIVES AIR

Depth (fsw)

50

100

Time (mimsec)

100:00

200

300

375

25:00

3:45

2:00

425

475

525

1:30

1:15

1:00

:30

resulting ^^^P^^P^ssure will lead to nitrogen saturation ofthe crew's tissues

SSIZJ^T*"TJf°*iM0 "" WatCT " *

e boat^ and Prior

supports the necessity to remove Steinke Hoods from USN submarines: Y

cold wZ* S?

D

S

S H0od

,

and life vests d0 n

°t give adequate protection from thermal stress in

^^'^^f"^ Shi

Uld

,

be^t0 ad°pting ** British Submarine EcSe -d ^miersion Suits (SEIS) for use m isolated or wartime situations. Major modifications of escape

timk would be necessary to adopt existing submarines to exploit the full 20^7esClZ

potential ofthe suit However, its potential for increasing survival potential in Swater could

be realized with only minor escape trunk modification in existing submarines^!)

12
The senior survivor must make his decision to escape while taking into account many

considerations, including compartment pressurization, hypothermia, C02, air embolism, ear drum

rupture, 02 depletion, and toxic gases. Upon making the decision to escape, the submariners are

confronted with the following Steinke Hood limitations: survival in the cold water with minimal

thermal protection (mimmal implying the inadequate insulation oftheir clothes), and the Steinke

Hood operational limits. While survival in cold water has been discussed extensively above an

additional constraint is that the Steinke Hood has only been successfully used to a depth of 318

fsw (97 msw) and simulated to a depth of450 fsw (137 msw). (20)

Hypothermia, the instantaneous effects of cold water immersion, and escape depth

limitations are the driving factors that require replacement ofthe Steinke Hood, currently

deployed on USN submarines, with equipment similar to the British Mark 10 SEIE or the

Swedish Mark VHISEIS. The need to replace the Steinke Hood on submarines due to its lack of

thermal protection has been noted a number oftimes over the last three decades During a

conference on "Medical Problems of Submarine Survivors" by Submarine Development Group

One in November 1978, the following recommendation (Priority A) was made:

"There is a definite problem in a disabled submarine with cold and subsequent

hypothermia and death ofsurvivors ofthe original accident. It is, therefore, strongly •

recommended that Submarine Escape and Survival Equipment (EASE) suits be provided to all

submarines m lieu ofthe Steinke Hood. Not only does the EASE suit provide for a better chance

oi survival after escape, it could be also used to protect survivors (from the effect of cold) while

awaiting rescue." (21)

Nine immersion experiments with a modified version ofthe Beaufort Mark 8 SEIE were

earned out m 40°F (4.4°C) water. Tests show that survival in good condition for 12 h in an

mtact suit is realistic. Moreover, the physiological measurements indicate that survival for 24 h

would be possible ifthe submariner is unhurt and able to keep his suit well inflated and drv

inside. (22) J

It is ofinterest to note that the RN has increased its research and development in

submarine escape vice rescue, and the British Mark 8 and Mark 10 SEIE are currently deployed

on their submarines. The development ofthe British Mark 10 SEIE provides escape and survival

equipment with breathing gas, buoyancy, and exposure protection for submarine personnel

escaping from the continental shelf and beyond. The Mark 10 SEIE specifications require 24 h

ofsurvival under conditions that could vary from 90°F (32.2 °C) water with 85 °F (29 4°C) air

still air and calm sea, to 29°F (-1.7°C) water with 10°F (-12.2°C) air, 30-knot wind speed and'a

sea state of 6.

Upon further analysis ofDr. Neuman's assumptions, the heart ofthe argument to replace

toe Steinke Hood must be focused on the hypothermic conditions that the submariner would face

from the tune that flooding ofthe escape trunk commences to the time ofrescue The Steinke

Hood affords no method ofthermal protection, and for this reason alone, the current method of

submarine escape is no longer practical.

13
RECOMMENDATIONS

1.

and incorporate automated system into the design ofNSSN. ^'

Develop and install more realistic, low-risk, cost-efficient equipment and trainine

procedures to support introduction of new escape equipment g

14
REFERENCES

1. Harvey, C, Carson, J. IMlLAiU^AOXm^^^

&^mira^^ NSMRL Special Report SP89-1, Naval Submarine

Medical Research Laboratory, Groton, CT, 1989.

t Newnan, T.S. Suhmmn^^ Naval Undersea

Medical Institute Thesis, Naval Undersea Medical Institute, Groton, CT, 1974.

3. Ikeda, T., and Oiwa, H. "Safe Individual Submarine Escape Training- Over 14 700

Uneventful Ascents in the Maritime Self-Defense Force." In: Proceedings - 9,0th L^

Meeiingj3fthe European Underwater and Baromedical Sociefamn Diving and Hyp^w

Me^cme, Cimstit, M., ed. Hyperbaric Medical and Research Center (HITAM), Istanbul, Turkey,

4. Benton, P.J., Woodfine, J.D., and Francis, TJ.R. Ajsyie^ai^pinar^^

esc^e_traming tanks incidents (1QS4-1003) using nbjertimdiagno^iic^cxiteria. INMR94011

Institute ofNaval Medicine, Alverstoke, UK, 1994.

5. Dr. T.S. Neuman letter, Subj: Submarine Escape, July 16, 1996 (on file in the Naval

Submarine Medical Research Laboratory, Groton, CT library).

6. Bernard, E.E.P Eaton, W.J., and Snow, R.E. Experiments in Snhm« F^ _?_~M

Compression ofMen to 6?5 Frei Royal Naval Physiological Laboratory, Alverstoke, UK, 1973.

7. Bell, P.Y., Burgess, D.W., Summerfield, M., and Towse, EJ. "The effect ofpresaturation on

toe maximum submarine escape depth of goats and the implications for human research "

Und£r^atexPJry^oJo^m, pgs 241-247, Undersea Medical Society, Inc., Bethesda, MD 1984.

®J Donald, K.W. Submarine Escape Breathing Air. A Review and Analysis ofAnimal and

Human Experiments by the Royal Navy, 15, 739-754, 1979.

9. U.S. Navy, SSN 637 ESCAPE BILL, Change 1, pgs 3218-1 to 3218-10.

10. Brown, E.W. "The Physiological Effects ofHigh Concentrations ofCarbon Dioxide "

Umted_Siales_^aval Medical Bulletin, Vol. XXVm, No. 3, pgs 523-553, 1930.

11. COMSUBLANT INSTRUCTION, 5400 Series, FLOODING BILL.

lu\Eal}^^dSwmaitJ-

K

-

Simulate^een Submarine Escape from 4QS w„f S

^

B^G^on CT 1°9°760

9025' ***** "^^"*"* ^^^ MediCal Cent6r'Submarine

MAVS8

A

6

;

T9"UST^"00/CH"594'IndMdua^^ Chapter 4, NAVSEA Techmcal Manual, Washington, DC.

15
14. Keatinge,W.R. SiimYaliiir^dmter. Blackwell, Oxford, England, 1969.

WrSColdT^h"* ^f1'

P

- "

ResPirato^ «* other Responses of Subjects immersed m Cold Water. Imimaljji^iplieii^^ 40:903, 1976.

17. "Organization ofmedical aid to victims ofthe sinking ofthe nuclear submarine

Kosomolets». Mmtar^Me^io.^aMU, p. 28-32, Nol 1989S2ZSion).

18. Perez, M. "To sink or swim - or both." SafetyJ^, Naval Safety Center, Norfolk, VA,

00^^^^^^Chapt6r 4' ^

S 4

"

15

'^« Naval Sea Systems

submldf6'

H,E-' ** Hu^EJ

- "

Conduct of a fleet operation investigation of a modified

submanne escape apphance.» Project Report ofProject F/OS2FY61. NAVSUBS^OL 25May

Submanne Development GrouTOmTsanD^^

16
ACKNOWLEDGMENTS

The authors express their appreciation to Dr. Tom Neuman for his original work, and for

his helpful comments on this paper. Constructive reviews were received from CAPTs Henry

Schwartz, John Murray, David Sack, CDR T.J. Reilly (Commanding Officer, USS BATFISH

SSN-681), and Chiefs Barnes and Lambertsen, U. S. Navy. Our thanks to Ms. Ellen Perkins for

manuscript assistance and Mrs. Elaine Gaucher for research assistance. The assertions and

opinions contained herein are the private views ofthe authors and are not to be construed as

reflecting the official policy ofthe United States Navy. This work was supported by Chief of

Naval Operations (CNO-873) through Naval Medical Research and Development Command project No. 63706N.M0099.01A.5602. P

17