How to judge seakeeping of semi-displacement hulls?

[jsc7]

I have some books on naval architecture, but I have not really studied them yet. Are there some basic ways to understand and predict how a particular boat might handle and ride?

For example, looking at two similar vessels, the Mainship 40 sedan bridge and aft cabin. These two boats are similar sized and both are powered typically by twin 350s. The sedan bridge has a single helm and day cruiser layout. The aft cabin has two helms, a flybridge and a right side standup pilot station. It is laid out more like a trawler, almost a tug.

Aft cabin typical:

LOA: 42 ft 2 in
Beam: 14 ft 0 in
Maximum Draft: 3 ft 4 in
Dry Weight: 24000 lbs

Sedan bridge:

LOA: 40 ft 0 in
Beam: 13 ft 6 in
Maximum Draft: 3 ft 5 in
Dry weight: 20000 lbs

The overall size and shape and performance seems to be somewhat similar. Are these boats going to have the same sea keeping characteristics, or will there be differences that can be estimated?

My general understanding is that some of the key factors are:

A. length to beam ratio

B. the position of the center of moment with respect to the waterline and the center of gravity

C. the hull shape

I guess the first problem is simply getting this information, which I do not know how to do for B and C. Then how do you take this information and translate that into an estimate of how the boat will behave in the water?

The main things I would be interested in computing would be stability (resistance to rolling) and seaworthiness (resistance to broaching and capsize). For both factors my novice guess would be that the most important thing would be the height of the center of moment, lower being better.