Panel Methods
Panel methods are a quick way to calculate flow around a ship.
Boundary Integrals
Michell's theory allows us to find the resistance of a ship only by calculating a triple integral. I have a Michell code spreadsheet which calculates the upright resistance from Michell's integral and the Delft series for a basic sailboat hull.
Michell's Theory
A boundary integral method can be a quick way to solve for potential flow. I've written a Boundary Value Problem paper which describes the mathematical formulation. I have also written a Submerged potential flow paper. It covers how to impliment sources and sinks into a MATLAB code.
FKS
FKS is a code developed primarily from the work of Dr. Noblesse from NSWC-CD. FKS uses a strip method in conjunction with Havelock theory. Here is an FKS review based on the Mk II Navy 44 STC.
SPLASH
SPLASH is a specialized CFD code for sailboats developed by Bruce Rosen. SPLASH uses a linearized free surface and calculates the wavemaking resistance of a hull as well as the sideforce the appendages generate. Here is a SPLASH review again based on the Mk II Navy 44 STC.