Ship Speed Evaluator (Springsharp Logic)

(Created 24 January 2025)

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 Speed to Evaluate (kts)

Friction Resistance
Power to Wave (%)
Wave Resistance
HP needed: (MW)

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)
0.672: CVE-105 Commencement Bay
0.711: BM-7 Arkansas Monitor (1898)