Your images indicate a confusion of deep-v vs displacement hulls; whereas what the intention is a displacement vs planing hull. Merchant vessels, and historic

Your images indicate a confusion of deep-v vs displacement hulls; whereas what the intention is a displacement vs planing hull. Merchant vessels, and historic sailboats (pictured), even the WWII troop carriers were displacement hulls. Traditional navy sail ships carried additional stones as ballast to create stability. Mono-hull sail boats use a deep weighted keel to increase stability. On a displacement hull, the deep-vee design increases stability when compared to a flat bottomed boat, and has more space for ballast (at a low center of gravity) Planing Hulls are more commonly used for recreation or speed, and are often those those that have a "deep-v" bow. Planing hulls are designed to lift mostly out of the water, while the deep-vee is across the beam and facilitates cutting through rough water. A deep-v displacement hull is great for crossing rough oceans, or keeping a boat stable as cannons are firing, but not a great choice for fuel efficiency or landing on beaches as a flat bottomed displacement boat. A planing hull is great when you have a modern gasoline engine and plan to be going > 15mph. A deep-vee allows that to come down through a wave, cut through the wave and lift back up. [Salinity would have very little effect on the stability of a planing hull as its stability is mostly provided by speed, though, launching or sitting would be unstable with it's half "flat" hull] About deadrise https://www.tropicalboating.com/2010/04/deep-v-shallow-v-or-variable-deadrise-hull https://www.tropicalboating.com/2010/04/deep-v-shallow-v-or-... The Vasa (Swedish Ship) is a great example of poor initial stability, center of gravity understanding, and how a deeper keel (with more stones) OR removing higher mounted cannons in briney water could have changed things. https://en.wikipedia.org/wiki/Vasa_(ship)#Causes_of_sinking https://en.wikipedia.org/wiki/Vasa_(ship)#Causes_of_sinking