How do you start a BIG engine?

Yes they do. Swinging such vessels is commonplace. In the vast majority of ports of which I have experience, you can’t go out the same way you came in. Because it is easier to swing a vessel in ballast (rather than loaded) ships come into the loadport, swing head down and berth, then load and depart, and do the opposite at the disport.

So how do they start a nuclear powered aircraft carrier?

Very very carefully

I was fission for an answer.

…moan…

I’m curious, is there a big starter button in engineering/the bridge on any ship? Something that would make a land lubber like me think “Ah, so simple”.

Well, there is the initial start of the reactor but once running I think it is always running to some extent till it needs to be refueled.

I certainly do not know the ins-and-outs of reactor startup but I imagine it involves putting the fuel in and moving the control rods which slow the reaction enough to allow fission to start. Pretty sure fission will start naturally in the reactor with the fuel in proximity to each other like that. No doubt a lot of things need to be happening parallel with this (coolant pumps running and so on). Doubtless there is more than a button push but perhaps it is that simple with a computer running things (and humans closely monitoring to make sure all goes as planned).

After that the nuclear reactor is really just a fancy way to boil water to make steam to turn turbines. Want the ship to go I guess you increase the reaction in the reactor and start boiling more and more water. Build up pressure, get the turbines spinning and away you go.

There is a lot of variety but generally speaking no. The big diesels used on commercial vessels are started by the engineers from the engine room, and there are a series of steps to go through involving turning on various pumps, closing this, opening that, before you can start it.

The captian tells the Chief Engineer when he wants to leave port. If the Chief agrees he will inform the engineering watch officer when to be ready to answer bells. The closest thingf to a start button is the EOT (engine order telegraph). The bridge will ring up stand-by engines as they single up lines.

A Johnny Popper? (Two cylinders opposed?)

Excellent links in this thread.

Why, yes, in fact I am a Big Machinery geek.