Question Why are ships modeled the way they are?

[Eric Sailcutter]

The problem is that the Brigs and Sloops look, to some degree, rather accurate to their real life counterparts, while the Frigates and Galleons don't.

Not really a problem, just an odd choice on Disney's part that is likely rooted in the cartoon nature of the game where, as River says, it's probably designed to appeal to kids.

 

[Grey Vice]

it's probably designed to appeal to kids.

Thats Disney for ya. Its like how they made the attack form of Sabers in game the way a Rapier would be used irl.
A Cutlass and Saber are basically the same thing (Cutlass is shorter).

It is one of those things that doesn't exactly conform to what we'd expect, but it makes it easier for the kids to recognize distinctions.