Demistifying Service Life
ASNE Flagship
18 Jan 2011
Chris Cable
Director, Auxiliary and Special Mission
Ship Design Division (SEA05D4)
Naval Sea Systems Command
Christopher.w.cable@navy.mil
(202) 781-1943
SERVICE LIFE – Outline
• Tell them what you are going to tell them
• Tell them
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Terminology
Why an understanding of Service Life is important
Current ESLs by class
Data on ASLs
Why do ships get retired before their ESL?
So what??
NEEC = Naval Engineering Education Consortium
• Tell them what you told them!
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SERVICE LIFE – The Story
Tell them what you are going to tell them:
1. An understanding of Service Life is important to all Naval Engineers.
2. Service Life Terminology is often misunderstood.
3. Expected Service Lives change over time.
4. Actual Service Lives seldom equal Expected Service Lives.
5. How we Design ships to meet Expected Service Lives needs more attention.
6. A pressing need is to develop innovative ways to get ships to make it to their Expected
Service Lives (NEEC might be able to help).
3
SERVICE LIFE – The Basics
Terminology:
ESL = Expected Service Life. The number of years ships need to be kept in service to achieve a
given force structure.
ASL = Actual Service Life. Chronological life from commissioning to decommissioning.
CASL = Class Avg. Service Life. Average ASL by class.
DSL = Design Service Life. The service life the ship is designed to achieve.
SERVICE LIFE REQUIREMENT. ICD, CDD, COR, SPEC, etc.
MID-LIFE = Mid life upgrades to get To ESL.
SLEP = Service Life Extension Program. Major upgrades to get BEYOND the ESL.
30 YSP = 30 Year Shipbuilding Plan. The Navy tool for projecting force structure.
RECAP = Recapitalization. Buying new ships to replace retiring ships and/or to maintain the desired
force structure.
Ref: Ship Service Life and Naval Force Structure, P. Koenig, D. Nalchajian and
J. Hootman, ASNE symposium, Engineering the Total Ship 23-25 Sep 2008
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THE BASICS - An Irreverent Look
The Basics:
Chronological View
Think of a “lifespan”
ESL
30 Year Shipbuilding Plan
D&C Margins
•Things you do “in utero” to ensure a healthy
start to life and room to grow (need more!!)
SLA
.
DSL
Mid-Life
SLEP
Recapitalization
ASL
CASL
Only death and taxes are certain.
These can change during any
period of your lifespan.
•Normal life expectancy
.
•Dad, take your Lipitor!
•Time for a quadruple bypass……
…while Mom thinks about your replacement?
•How long did you live?
•How long did you family live on average?
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SERVICE LIFE – Why Important?
It is the foundation of the shipbuilding plan, the basis for recapitalization
Excerpts from the CNO’s Guidance for 2011 (Oct 2010): (emphasis added)
“Continue to be the most dominant, ready and influential naval; force, globally and across
all naval missions.”
“…conducting essential maintenance and modernization to ensure units reach
full service life…”
“Build a Navy with appropriate force structure and strategic laydown necessary to
implement the Maritime Strategy.”
“We must maintain the Fleet we have to the end of its expected service life…”
6
SERVICE LIFE – ESLs by Class
Current ESLs by class:
Ship
Class
ESL
1986
ESL
1990
CVN 68
FFG 7
30
35
ESL
1992
45
ESL
1995
Prop
45
35
20-25
PC
ESL
2006
ESL
2007
50
50
ESL
used in
Yr Plan
50
30
30
30
30
35
35
35
35
35
40
35
35
35
15
CG 47
40
40
25 n/VLS
35 VLS
35
20n/VLS
30-35
VLS
35
35
DD 963
30
40
40
DDG 51
30
40
40
DDG
1000
ESL
1998
35
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SERVICE LIFE – ESLs by Class
Current ESLs by class:
Ship
Class
ESL
1986
ESL
1990
ESL
1992
ESL
1995
Prop
ESL
1998
LCS
LPD 17
ESL
2006
ESL
2007
25
25
ESL
used in
Yr Plan
25
40
40
40
40
40
LSD
41/49
35
40
40
40
40
40
40
40
LHA 1
35
35
35
35
35
40
35
35
LHD 1
35
40
40
40
40
40
40
40
T-AO
35
35
35
35
35
35
35
35
40
40
40
40
40
T-AKE
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SERVICE LIFE – ESLs by Class
Current ESLs by class:
Ship
Class
ESL
1986
MCM
30
MHC
ESL
1990
ESL
1992
ESL
1995
Prop
ESL
1998
JHSV
35
ESL
2007
ESL
used in
Yr Plan
30
30
30
30
30
30
30
30
30
30
30
30
30
strike
40
40
40
40
40
40
20
20
20
MPF(F)
MLP
T-ATF
ESL
2006
35
35
35
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SERVICE LIFE – Why ESLs change over time
Why do ESL change over time?
Many factors:
• Force Structure evolving (build up)
• Force Structure evolving (build down)
• Stroke of the pen
• Balance the plan
• Engineering insight (but not enough of the time!)
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SERVICE LIFE – CASL info
Data on ASLs
Class
CASL
Latest or Current
ESL
FFG1
21.3
35
FF1052
21.1
35
DD963
23.6
35
FFG7 Flt 1&2
18.4
30
CG47 blk 1
19.6
35
CV63
40.4
45
CV67
38.6
45
CVN65
50 y ESL
55
LPD1
33.2
35
LPD4
Some 40+
35
LSD36
30.5
35
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SERVICE LIFE - Does ASL correlate to displacement?
Service Length as a Function of Displacement
Note: Includes all decommissioned Cruisers, Destroyers, Frigates, and Patrol Craft built after World War II. Active ships not shown.
18,000
16,000
Answer = Yes
Full Load Displacement (tons)
14,000
12,000
10,000
8,000
6,000
4,000
2,000
0
0
3
6
9
12
15
18
21
24
27
30
33
36
-2,000
Years in Service
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SERVICE LIFE - Does CASL correlate to
Displacement
Class Average Service Life (CASL) as a Function of Displacement
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Length of Service (Years)
30
25
20
15
Cruiser
Destroyer
Frigate
Patrol
10
Answer = Yes
5
PG 84, PG 92, PHM 1, PC 1,
PGH 1, PGH 2, PCH 1
0
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
Full Load Displacement (Tons)
Note:
Includes
Cruisers,Destroyers,
Destroyers,
Frigates,
Patrol
built
after World
II. Active
not show.
shown.
Note:
Includesall
alldecommissioned
decommissioned Cruisers,
Frigates,
andand
Patrol
Craf tCraft
built af
ter World
War II. War
Active
ship claships
sses not
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SERVICE LIFE - Does ASL correlate to multimission vs. single-mission
40
Answer = Maybe
35
30
Years ASL
25
20
15
10
5
0
LFS, LST, LKA, LPA
Single mission ships
LSD, LPD and LPH/LHA
Multi-mission ships
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SERVICE LIFE - “Birth date” matters because of
external events
Decommissioned - - 75 ships
13
12
11
1,700,000
Commissioned (no longer active) - - 75 ships
1,600,000
Commissioned (Active) - - 33 Ships
1,500,000
Total Displ. (Tons) of WW II Amphibs
1,400,000
1,300,000
Total Displ. (Tons) of Post WW II Amphibs
10
1,200,000
10-19 years
apart
9
1,100,000
1,000,000
8
900,000
800,000
6
700,000
5
600,000
4
500,000
3
400,000
300,000
2
200,000
20
04
20
02
20
00
19
98
19
96
19
94
-200,000
-400,000
-4
19-25 years apart
-500,000
-600,000
-5
-7
-100,000
-300,000
-3
-6
19
92
19
90
19
88
19
86
19
84
19
82
19
80
19
78
19
76
19
74
19
72
19
70
19
68
19
66
19
64
19
62
-2
19
60
-1
19
58
0
19
56
100,000
0
19
54
1
19
52
Number of Ships
7
-700,000
1970-1973: Vietnam budget
crunch. 23 ships out.
-800,000
-900,000
-8
-1,000,000
-9
-1,100,000
-10
-1,200,000
-11
-12
-13
-14
Displacement (Tons)
92% of all Amphib commissionings occurred
in 1953-1958 or 1968-1972.
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-1,300,000
69% of all Amphib decommissionings
occurred in 1970-73 or 1992-95.
1992-1995: Post-Cold War
Downsizing. 29 ships out.
-1,400,000
-1,500,000
-1,600,000
-1,700,000
Note: LPD 17 commissioned in January 2006.
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SERVICE LIFE – Factors for Early Retirement
Why do ships get retired before their ESL?
Many possible factors:
• Treaties
• Stability issues
• Mission system unable to meet threat
• Material Condition
• Damage (grounding, fire, high sea state structural damage, etc)
• Loss (wartime)
• Business Case (cheaper to build new??)
• Industrial Base considerations
• Environmental Considerations (ex: double hulling)
• Changes in the nature of the threat (Littorals, BMD, etc)
• Costs to operate (Fuel Efficiency, Manning costs, etc)
• Cost to get to ESL are prohibitive
• Mission goes away
16
Same ship, two missions
DE 1035 USN 1958-1974 =
only 16 years due to being
ineffective against nuclear
submarines
Then as Indonesian DE 342, served
1974-2007+ = 33+ more years as
gunboat
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SERVICE LIFE – DSL info
•1970’s to Early 1990’s
• GENSPEC was not specific about Design Service Life.
• Some editions made oblique reference to a presumption that ships generally would
be in service for 25 years.
• Thus the assumption of a 25 year life for surface ships (with no growth or mods
occurring in the last five years).
• Some of our margin policies (e.g., required electric plant service life allowance) have
been indexed to that number for many ship classes.
• With respect to the hull, fatigue life was not a controlling factor.
• Structures folks assumed their designs had enough margin that, provided you
repaired any degradation as it occurred, the hull would last an unlimited duration.
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SERVICE LIFE – DSL info (cont.)
•LPD 17 (early 1990s) onward
• LPD 17 = 1st program where we dealt with DSL meaningfully.
• Requirement was set for a 40-year ship life.
• Whole ship FEM models have been built for LPD 17, but in terms of validation to
demonstrate that the hull meets the fatigue requirement, the methods used there were
simplified in comparison to the process used today.
• All ships (except JHSV) after LPD 17 had OPNAV-specified ESL requirement.
• On JHSV they said essentially "I'll let that float in the interests of cost and will take what I
get.”
• Though OPNAV typically uses ESLs as "planning numbers" to guide a range of activities,
few people understand that they have no direct basis in engineering for older ships.
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SERVICE LIFE – Service Life Allowance
Service Life Allowances (SLAs) – when delivered each ship shall be capable of
accommodating growth during its service life w/o compromise of hull strength, reserve
buoyancy and stability characteristics. Anticipated growth consists of authorized changes
(like ship alts and mission upgrades) as well as unauthorized changes (like too much paint
and extra coke machines).
SLA NOT THE SAME AS DESIGN MARGINS
SLAs for Weight, KG, Electrical, A/C, Hull Strength, Accommodations, Fatigue Life
Notes:
• As SLA consumed, performance characteristics degrade (speed is at delivery).
• Major modification / conversions typically account for providing SLA compensation.
• When SLA fully consumed, may need Weight and Moment Compensation.
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SERVICE LIFE – So What?
So What?
Excerpts from the CNO’s Guidance for 2011 (Oct 2010): (emphasis added)
“We will continue to pursue affordable warfighting solutions that emphasize evolutionary
vice revolutionary capabilities, common hulls and airframes, open architecture, modularity,
lower energy footprint, and reduced manpower.”
Design ships to meet their ESLs -- develop the engineering understanding of the
technical underpinnings to Design Service Life.
• SFA
• Corrosion Allowance / high performance materials.
• More mission modular – maybe. Business case? Nobody doing it commercially?
• Open architecture (broadly) – probably.
• Aircraft Carrier example – you can argue that Carriers have such long lives because the
aircraft are the modular mission packages.
Innovate with new ways to help existing ships meet their ESLs (Goal: ASL=ESL)
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USS Midway, 1945-1992, 47 years
Modular combat system??
1945 prop Hellcats 1991 supersonic Hornets
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SERVICE LIFE – So What? (cont’d)
So What?
Excerpt from the CNO’s Guidance for 2011 (Oct 2010): (emphasis added)
“We will lead Science, Technology, Engineering, and Math (STEM) education and outreach
to grow top technical talent to lead tomorrow’s Navy…”
NEEC – Project based education – we need to get SUSTAINMENT projects in front of the
students
Contact for Project ideas: NEEC Director = Mr. Steve Ceccio
(possibly develop the course: what every Naval Engineer Needs to Know About Service Life)
Contact for Mentoring : Mr. Bob Keane
Innovate with new ways to help existing ships meet their ESLs
Predictive Tool. Project Ideas. “What every Naval Engineer needs to know about service
life”
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SERVICE LIFE – Summary
Tell them what you told them!
1. An understanding of Service Life is important to all Naval Engineers.
2. Service Life Terminology is often misunderstood.
3. Expected Service Lives change over time.
4. Actual Service Lives seldom equal Expected Service Lives.
5. How to Design ships to meet Expected Service Lives needs more attention.
6. A pressing need is to develop innovative ways to get ships to make it to their Expected
Service Lives (NEEC might be able to help!).
24