Sim:Main Page/

From The Dreadnought Project
Jump to: navigation, search

Welcome, Computer Science 39K students.

I hope you find my simulation of World War I technologies novel and compelling. The computing innovations often associated with the WW2 era really had an overlooked pre-history, as I am sure these videos will make clear.

I am reachable by email as "tone" through this same domain.


Torpedo Directors

Early in World War I, sights like the Torpedo Director Pattern 2006 were the means by which the Royal Navy aimed its torpedoes from surface ships. The torpedo directors allowed the proper sighting angle to be calculated by using the estimated enemy speed and heading as inputs into a mechanical analog computer.

Simple Case -- Director Mounted on Tube
When the torpedo director could be mounted on or near the tube, the geometry was simple.
Aiming Torpedoes with a Torpedo Director, part 1
Tricky Case -- Director Mounted Remotely
When the director could not be placed near the tube whose fire it would aim, the Royal Navy used an additional piece called a tangent bar to cause the sighting line and fire line to converge upon the target. This addition was later (rightly) viewed as preposterous, given the errors likely to exist in the hypothesis of enemy speed and heading, not to mention the likelihood that he would maneuver before the torpedo arrived.
Torpedo Director with a Tangent Arm, part 2

Epilogue: midway through World War I, the Royal Navy decided to discard the calculating torpedo directors in favor of simpler Torpedo Deflection Sights, which left the calculation of the sighting angle to others and simply applied it in the form of the speed the enemy was making across the field of view.

Fire Control

Naval guns have sights which, when the proper range and deflection (the small lateral aim-off angle) were entered would offset the sighting telescopes such that when the crosshairs were on target, the shells would hit the enemy. However, to hit a moving enemy repeatedly, one has to have a means of calculating the proper range and deflection continuously. This is the fire control problem - a real-time computational challenge in which the input data are unreliable and the stakes extremely high.

The Dumaresq Rate-Solver
The dumaresq permitted the fire control team to examine the relationship between the course and speed of two ships to the resulting "range rate" (how range was changing over time) and "speed across" (how quickly is the enemy ship steaming across the field of view). These derivative data were essential in modeling the range and deflection continuously.
The Dumaresq
Dreyer Fire Control Tables were elaborate geometry workbenches incorporating a dumaresq and a range clock to integrate a calculated range rate to generate a continuous, discretely encoded signal of present range. It, and its peripheral appurtenances, transmitted range and deflection to the battery's gunsights. Its sophistication, for the era, is largely overlooked today -- it had visual data displays and was well suited to help users unravel the noise in the range estimates they were being provided.
The Dreyer Fire Control Table
Director Firing
The final gem of the Royal Navy's toolset was a complete system of director firing, which permitted all the heavy guns of a battleship to fire harmoniously under the control of a centralised gunsight situated high above the water.
Director Firing

More Info