there are far more than two main kinds of submarines. The only two sections I can think of to separate them are fast attack and Boomers or Ballistic Missle.
The two main kinds are discrete and continuous.
kinetic and potential
consumers and producers.
indentured and chattel .|.
The early SS and the newer GATO Class diesel submarines.
quiet and explosive
There are now 'Attack' submarines who's main purpose is to sink enemy submarines and ships and also Missile submarines whose main purpose is to launch ballistic missiles at the enemy.
1. Ballistic submarines 2. Attack submarines
Sail boats and power boats are the two main types of pleasure craft.
The two main types of swamp are "true" or swamp forests and "transitional" or shrub swamps.
The action verb and the linking verb.
Eucalyptus and Australian acacia