Need to calculate the draft of a boat

I am trying to find the draft of a boat. This is what I know.
The boat is 12'wide X 20' long X 10' deep.
The material for the boat is steel and weighs 10.2 lbs per sq/ft.
So I need to find the weight of the boat as a starter.

I will be putting this in sea water using 64.08 lbs per cubic/ft.

Can anyone give me a formula to tie all this together?
Appreciate the help.

 

No formula only hard work

You really need to know what you want for the hull before you can design anything. The use of the vessel would be a good start.
Could I suggest you try and read a book called (I think) "How to design a boat" by John Teal.

What you have to do is

1esign a hull to a desired displacement and ratios
2:Calculate the masses and moments of all the parts in the finished vessel
3: Add ballast and or go back to step 1 and change displacement.

and so on.............

The steel weight should be cubic too !