It's important to recognize and accept ships for what they are...
First off we have the classic "Sailboat"
http://loewshotelsblog.com/wp-content/uploads/2015/09/Sailboat-sunset.jpg
Ahh yes, the Classic ships. These ships are for the most part canonical in one shape or another.
These are ships such as:
x
x
x 
Next up is the Submarine ships!.. They are kinda a ship, quiet now.
http://65.media.tumblr.com/d21961214d06f59586c7050ecfe5dcb4/tumblr_n1cijemddT1ttdyato1_1280.jpg
These ships are the hidden gems, the oddballs. They have some connection in one shape or another. These ships arnt too popular and / or well known about.
These are ships such as:
x
x
x 
Next are the Battleships!
https://maxgrace.files.wordpress.com/2009/10/battleship_003.jpg
These are ships that Mortal enemies come together... for whatever reason or another.
These are ships such as:
x
x
(and or)
x 
DISCLAIMER: I do not condone any heresy, these are merely used as an example
Next we have the Ironside ships. Its the name of one but whatever...
http://www.karenmillerbennett.com/wp-content/uploads/2012/10/Old-Ironsides.jpg
These ships have stood the test of time and will never falter.
These are ships such as:
x 
Next up is the Cruise Ship.
http://i2.cdn.turner.com/cnnnext/dam/assets/160108142736-regents-seven-seas-explorer-super-169.jpg
These ships are fun community made ships. Most ships also fall under this category. All have a good time on the cruise.
These are ships such as:
x
x
x
x
x
x 
Lastly we have a subcategory of the Cruise Ship called the Titanic
https://i.ytimg.com/vi/c5cFoRLeVZw/maxresdefault.jpg
x 
X 