John Pledger: Launching Calculations

"Very careful calculations had to be made first of all, to make sure the ship will actually move when you ask it to and then when it's released, it will accelerate at an acceptable speed and not go mad. And it won't capsize in a semi-floating position because when half of it's still on dry land and the other half is in the water, you've got a very funny stability calculation to make. And also it doesn't tip off the launchway, you know, it's going down and the front end suddenly lifts off the launchway or something nasty like that. Or worst of all that it does in fact capsize during launch and that latter event is not altogether unknown."