Ship Speed Evaluator (Springsharp Logic) v2

(Updated October 2026)

Over twenty years ago, there was a program called 'SpringSharp' which was decently good in estimating ship speed/horsepower required. I decompiled the version 2.1a executable and reverse engineered the program logic from that; then validated this in-browser Javascript implementation against the original executable for the same inputs. This will allow quick online based evaluations of surface ship speeds for the aspiring Naval Analyst.

SHIP SPEED/PROPULSION VARIABLES

Pre-Set Inputs



: Length (Waterline) (ft)
: Beam (Waterline) (ft)
: Beam (Bulges) (ft)
: Draft (ft)

Transom Stern?

Set Block Coefficient (must be from 0.3 to 1.0) or enter Normal Displacement

: Block Coefficient
OR
: Displacement (long tons)

Waterplane Area (square feet)
Wetted Surface Area (square feet)
to 1 Length/Beam Ratio
Natural Speed (kts)

: Set Top Speed (kts)
: Fuel Fraction (decimal)
Fuel Bunker (long tons)
: SFC (kg/kWh)
Speed (kts) Friction Resistance Power to Wave (%) Wave Resistance HP Needed MW Needed MW Surplus Endurance (days) Endurance (n.mi)

Block Coefficient Examples:

0.438: FFG-7 Oliver Hazard Perry
0.457: CV-4 Ranger
0.497: DL-2 Mitscher
0.498: Virginia DLGN/CGN
0.499: DD-445 Fletcher
0.501: CC-1 Lexington (1916 Design)
0.502: DD-692 Allen M. Sumner
0.502: Truxtun DLGN/CGN
0.505: DE-339 John C. Butler (WGT)
0.518: DE-5 Evarts (GMT)
0.525: CL-55 Cleveland
0.525: CA-68 Baltimore
0.527: CV-6 Enterprise
0.539: CB-1 Alaska
0.540: DD-710 Gearing
0.543: CA-134 Des Moines
0.546: CL-144 Worcester
0.550: BB Bismarck
0.564: CV-2 Lexington
0.571: DL-1 Norfolk
0.573: CV-9 Essex
0.580: CVA Kitty Hawk
0.593: BB-61 Iowa (1940)
0.600: BB-29 North Dakota (1910)
0.603: CVAN-65 Enterprise
0.610: Queen Mary II Superliner
0.616: BB-35 Texas (1911)
0.622: BB-56 Washington (1937)
0.628: CVA-67 John F. Kennedy
0.662: BB-49 South Dakota (1918)
0.665: BB-67 Montana (1941)
0.669: Maine (1895)
0.670: Susan Maersk (9578 TEU C-Ship) (1997)
0.672: CVE-105 Commencement Bay
0.711: BM-7 Arkansas Monitor (1898)

Fuel Fraction Examples:

0.2213: PHM-1 Pegasus
0.2008: DD-963 Spruance
0.198: CG-47 Ticonderoga
0.179: DDG-993 Kidd
0.1766: FFG-7 (Short Hull)
0.1589: FFG-7 (Long Hull)
0.1371: BB-61 Iowa (1945)

SFC Examples (kg/kWh):

0.429: KGV Steam Turbine (Late 30s)
0.337: Graf Spee Diesels (Late 30s)
0.256: LM2500 Gas Turbine (1970~) (@80F)
0.246: MT30 Gas Turbine (2000~) (@80F?)
0.180: Wärtsilä 12V46C Diesel (2000s)

Tidbits:

  • One Gallon of F-76 Marine Diesel weighs 0.003167 long tons per US Gallon.

  • BB-61: 7,892 long tons of fuel oil on 57,540 long tons displacement.

  • FFG-7: [Information Sheet 64P7-101] (205,000 gal / 651.51 long tons of F-76) on 3689 (short hull FFG-7) 4100 (long hull FFG-59) tons displacement

  • DD-963 Spruance: [64P8-101] (510,000 gal / 1615.17 long tons of F-76) on 8040 tons displacement

  • DDG-993 Kidd: [64P8-101] (553,000 gal / 1751.351 long tons of F-76) on 9783 tons displacement

  • CG-47 Ticonderoga: [64P8-101] (620,000 gal / 1963.54 long tons of F-76) on 9915 tons displacement

  • PHM Pegasus (62,762 liters / 16,580 gal / 52.5 long tons of F-76) on 237.19 long tons full load displacement (LINK).

  • "The costs to operate the squadron command, Mobile logistics Support Group (MLSG) and the six hydrofoil [PHM] ship was at that time 6% of SURFLANT's annual budget. The ships actually could run on diesel fuel or JP-5 fuel. JP-5 fuel was primarily used to keep the fuel injectors cleaner. During hull ops fuel consumption was 230 gallons per hour for the two diesel engines and the two ships service power units (SSPU). During foil ops we used 1035 gallons per hour." (LINK)