There are very few things more impressive than the Iowa Class battleships.  They were the pinnacle of the gun at sea at the same time the gun as main weapon was more or less obsolete.

Here’s an interesting post from Ars techinca.

Some pictures from Sploid.

An article about a proposal to modify the Iowas.  There were a bunch of these over the years.

Here are some mages from “Naval Ordnance & Gunnery,” a vintage ordnance manual that I found in a bookstore a long time ago.  It’s a instruction manual for battleships, along with stuff about torpedoes, mines and other ordnance related stuff from just after WW2.


A cutaway an Iowa class gun turret.


Plan views of the various turret levels.





Diagram of the shell hoist.


And the gun rammer.


A side view of the 16″ 50 calibres main gun.


When guns became more powerful in the late 19th century due to metallurgical advances making steel guns feasible ranges got much longer.  That lead to a new problem.  How to put the shell on target when the target won’t be in the same place when the shell lands.  That requires some method of predicting where the target will be, where you are and conditions between you and the target.  It was also discovered that you were better off firing your guns from central director aloft rather than from the gun station itself.  This  became the science of fire control.

The idea was place the operators of the guns as high as possible so that the training and rangefinding could reach out as far as possible.  So the gun director was placed on top of a mast or tower.  The Director would feed target information to the plotting room deep inside the ship which would take that information and use it, pus some other information to tell the director how to train and elevate the gun to put the shell where the target is going to be rather than where it is.

This information is obtained using a plotting machine or in the Iowa’s case a mechanical computer.  The results are then fed back to the director which updates the training and elevation of the guns and delivers the firing command when the guns are ready. You can see the main directors on the top of the steel towers on most battleships after WW1.  If you look at paintings of battleships it’s not unusual to see the director with it’s rangefinder pole pointed straight forward as the guns are firing vigorously trained over one side.  That’s because the artist used a model of the ship in question and didn’t know what the director did.

Anyway, here’s some info from “Naval Ordnance”

The typical arrangement of the last US BB classes.


The fire control computer.


A schematic showing how fire control worked.


The arrangement of a Mark 34 director used on Iowa Class BBs.


A connection schematic for a Mark 34 director and fire control.


A navy training on the fire control.

A rather nasty little film.

A US Navy training film showing the process of loading and firing the guns.

The last time an Iowa fired it’s guns.  What all this was for.




  1. dougirvin · October 25, 2015

    When I lived in Bremerton, Washington, one of the places I visited was the USS Missouri, where the Japanese surrender took place. I could imagine the thoughts going through the Japanese envoy: “Damn! We sunk this! What’s it doing here!?! An impressive piece of warfare. I couldn’t explore the ship – much as I wanted to – but it was still memorable.


  2. Pingback: A Small Pet Peeve, Naval Fire Control And Battleship Paintings | The Arts Mechanical

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