I have always seen the ship computers as something to the old Sicomp-M series (The Boys as my old boss called them). Highly specialised process control systems with an extremly rugged and redundant hardware setup.
This page has something on the M80, the final member of the series but the more common M70 and M76 series are about the same size. Most commonly used in
+ Nuclear power plants (All german/KWU plants use it)
+ Coal fired power plants (Either M or R-series)
+ Mining (All german mines used it till the 2000s)
The actually could work without an environmental control if necessary. That "5-45 degrees celsius" was a recommendation, nothing more.
They where beautiful maschines working at 99.99 and better reliability handling 1000+ A/D inputs per second. Dual box (Two CPU/Data access, 2 Disk towers, 1 switching unit) in mining and IIRC 2x3 (Two mirrorer tripple boxes) in the nuke plants. You could hot plug cards and on a few occasions the Siemens techs soldered wires on a life box.
And the grafik terminal where simply a great design. Basically an 8bit CPU with a dedicated 6845 CRT Controller and 64KB (yes Kilobyte) of memory for the grafics. Quite smart boxes doing some procession on their own and sturdy enough that a grown man could stand on them. Typically stacked (there where two in grafic terminals) and used as a footrest. Basically the size of a SparcStation each.
The pulled their final "hurray" in the mining jobs when the "supperior follow up" system was unabel to do their job for almost 2 years after the sheduled replacement date. God, I miss those boxes. Big, rugged, serviceable with an electronics soldering iron and with handbooks. Ohhhh the handbooks.