3. K80531_005 _OS
10/20/98
Higher speeds in higher seas
provides operational advantage
Higher speeds in higher seas
provides operational advantage
The Designer’s ChallengeThe Designer’s Challenge
Wave Height
K80531_005 _OS
10/20/98
Higher speeds in higher seas
provides operational advantage
Higher speeds in higher seas
provides operational advantage
Speed
Calm Moderate High
Current
Desired
Small Ship Performance
4. K80531_002_OS
10/20/98
HullformsHullforms
Advanced hullforms – designed to enhance performanceAdvanced hullforms – designed to enhance performance
Displacement
Dynamic Lift
Monohull Catamaran SWATH/SLICE
Planing Hull Hydrofoil ACVM SES
Single Hull Twin Hulls Submerged Hulls
Hull Lift Foil Lift Air Cushioned Lift
6. Operational in High Sea StatesOperational in High Sea States
Replenishment
and Amphibious
Battleships
Carriers
Destroyers
Frigates
Mine
Sweepers
Tugs
25
15
10
6
3
0 300 600 900 1200
Ship Length (ft)
WaveHeight(ft)
Navatek II
SLICE Navatek I
Sea
Shadow
AGOR 26
TAGOS 19 & 23
Highest Fully Operational
Wave Height
Kaimalino
Kaiyo
Small Waterplane Area Ships (SWATH)
Provide Operational Capability in High Sea States
7. Ship Motions in a SeawayShip Motions in a Seaway
RESONANCE
WAVE FOLLOW
WAVE
INTEGRATION
SHIP HEAVE MOTION
DEPENDS ON MASS AND WATERPLANE AREA
WAVE PERIOD
0
1
2
3
RESPONSE
HEAVE / H wave
Mass (virtual)
T resonance (sec) = 2 p
Waterplane Area
SHORT LONG
8. Why SWATHs Are
Operational in High Sea
States
Why SWATHs Are
Operational in High Sea
States
• Resonance period T is defined by
T = 2π ([mass / waterplane area )1/2
• For SWATHs waterplane area (wpa)
is typically 1/6 the wpa for monohulls
or catamarans of equal displacement
• Thus, the period for SWATH ships is
2.5 times longer than for monohulls
or catamarans of equal displacement
• When compared to Sea State Energy
SWATHs Resonance is above Sea
State of operations
Wave Period (sec)
5 10 15 200
Sea State 6
5
4
3
SeaStateEnergy
Monohull
AGOR 24
3200 LT Displ SWATH
AGOR 26
2550 LT Displ
11. Video of navatek IIVideo of navatek II
QuickTime™ and a
Sorenson Video decompressor
are needed to see this picture.
12. K80531_003_OS
10/20/98
SpeedSpeed
Conventionally, speed requires lengthConventionally, speed requires length
Replenishment
and Amphibious
Battleships
Carriers
Destroyers
Cruisers
Frigates
Mine
Sweepers
Tugs
Limiting Speed for
Displacement Ships
40
30
20
10
0
0 300 600 900 1200
Length on Waterline, L (ft)
Speed(kts)
High
Wave Drag
13. K80531_003_OS
10/20/98
SpeedSpeed
Speed Limited By Wave ResistanceSpeed Limited By Wave Resistance
Replenishment
and Amphibious
Battleships
Carriers
Destroyers
Cruisers
Frigates
Mine
Sweepers
Tugs
Limiting Speed for
Displacement Ships
40
30
20
10
0
0 300 600 900
Length on Waterline, L (ft)
Speed(kts)
High
Wave Drag
Viscous
Wave
Froude No. = V/√g*L
0 0.4 0.5 1.51.0
14. K80531_013 _OS
10/20/98
Resistance – Wave / ViscousResistance – Wave / Viscous
0 0.4 0.5 1.0 1.5
ResistanceCoefficient Cargo Ships
Liners
Battleships
Aircraft Carriers
Cruisers
Frigates
Destroyers
(15 kts)
(22 kts)
(28 kts)
(36 kts)
(30 kts)
(30 kts)
(35 kts)
500 ft
850 ft
890 ft
1100 ft
560 ft
450 ft
560 ft
Viscous
Froude No. = V/¦gl
Wave
At “Hump” Froude Number Wave Resistance is Greater than 50% of TotalAt “Hump” Froude Number Wave Resistance is Greater than 50% of Total
17. K80531_005 _OS
10/20/98
Speed in a SeawaySpeed in a Seaway
Only low-waterplane area SWATH ships
maintain speed in high seas
Only low-waterplane area SWATH ships
maintain speed in high seas
Wave Height
Speed
Calm Moderate High
Displacement
Hulls
Monohull
Catamaran
SWATH/SLICE
Dynamic
Lift
Planing Hull
Hydrofoil
ACVM SES
27. Wake Wash PerformanceWake Wash Performance
COMPARISON OF VESSEL WASH
ENERGY DENSITY
0
5000
10000
15000
20000
25000
0 5 10 15 20 25 30 35 40 45
Vessel Speed (Knots)
WashEnergyDensity(Joules/Meter)
WA State Ferry
Standard
FBM TRICAT - SASSACUS
NYFF - BRAVEST (GEE)
AMD 385 - CHINOOK
SLICE
Lowest Wash Energy Measured to DateLowest Wash Energy Measured to Date
28. K80531_012 _OS
10/20/98
HullformsHullforms
SLICE operates at higher speed
while retaining SWATH’s low motions
SLICE operates at higher speed
while retaining SWATH’s low motions
Wave Height
Speed
Calm Moderate High
Displacement
Hulls
Monohull
Catamaran
SWATH/SLICE
Dynamic
Lift
Planing Hull
Hydrofoil
ACVM SES
SLICE
SWATH
29. K80531_015 _OS
10/20/98
Technology AdvantagesTechnology Advantages
Commercial ship operators want small, affordable ships
that operate at high speed in high seas
Commercial ship operators want small, affordable ships
that operate at high speed in high seas
• Length required for speed
• Size required for seakeeping
(stability) in high seas
• All the SWATH advantages,
plus more capability
– Higher speed
– Lower wake
– Better range, endurance,
fuel consumption
• Affordable
– Acquisition
– Life cycle
• Conventional shipyard
practices
– Design
– Construction
– Material and equipment
• Length still required for speed
• Smaller size but better
seakeeping
• Less costly
– Acquisition
– Operating
Conventional Hulls
Single Hull Twin Hull Submerged Hull
SWATH Hulls SLICE
30. K80531_016 _OS
10/20/98
Candidate SLICE MissionsCandidate SLICE Missions
• Drug interdiction
• Coast Guard search & rescue
helicopter
• Environmental cleanup and oil spill
recovery
• Pilot boat
• Mission launching platform
• Sonar surveillance craft
• AUV/UUV underwater vehicle
support
• Test range support
• Command, control &
communications platform
• Mine countermeasures
• Range support
• High-speed ferry
• Cruise ship
• Casino boat
• Offshore oil support vessel
• Tourist excursions
Government
Commercial
Military
32. Streetfighter LCS(X) National Security Vessel
Sea Shadow Offshore Patrol Vessel EWSS
Military ApplicationsMilitary Applications
Speed in High Sea States Offers
a Wide Variety of Military Applications
Speed in High Sea States Offers
a Wide Variety of Military Applications
33. SLICE is a demonstrated technology
allowing small, affordable ships
to operate with safety and efficiency
at high speeds in high seas
SLICE is a demonstrated technology
allowing small, affordable ships
to operate with safety and efficiency
at high speeds in high seas
K80531_017 _OS
10/20/98
SummarySummary
