A Submariner
A submarine.
someone who sails.
Tosser
They are referred to as four-cornered sails.
They were referred to as "four-cornered" sails.
I don't think there is another name other than blade.
Sails are attached to the mast.
Someone who repairs boat sails is called a sailmaker or sail repairer. These professionals specialize in sewing, mending, and maintaining sails to ensure they are functional and durable for use on the water. Their work may involve patching holes, reinforcing seams, and sometimes even designing new sails.
A submarine is an undersea boat, or submersible.
The Nautilus was Fulton's submarine.
Below
plunger is a fitting name for submarine because , it is under the water