LPS and AVS should be the same value, since they are describing the angle at which positive stability equals zero. The US Sailing number is only a rough approximation, which for my boat is pretty close to right. A proper LPS calculation calculates the vertical, lateral and longitudinal center of gravity and then models the center of buoyancy as the boat heels until it locates the angle at which the center of gravity is directly over the center of buoyancy which only occurs at three points, LPS, and level at rightsideup and upside down. There is also an IMS AVS which is calculated for all boats that are rated under the IMS rule. This number does not add for the cabin structure or deduct for rigging weight and so typically yields a low number for most racercruisers.
Jeff
