Like when I'd check the time it'd take to build the Galaxy boat from the t3 shipyard it said like 45 minutes! Did I miss something important? I had enough energy and mass coming in to sustain its construction..
Then the world is about to turn for you my friend.
The more engineers you dedicate to a construction job, the faster it builds.
The downside of this is that it has a real hit on your mass/energy production and can rapidly deplete it if you go overboard. But in theory - I suppose - if you had the mass/energy income you could dedicate enough engineers to a job that you could be pumping out a battleship every second*
*Assuming theres enough space around the shipyard for them all to fit!
Suffice to say - to get an engineer to assist with a job, click on the engineer and then right click on the construction job. It'll then help out with the building.