But realistically, for the special project to even be a viable economic option, you have to have defeated the Dreadnought already without too many losses. Now you might argue that the relative value of the Dreadnought can be much higher, because you could have lots of researchers but a weak fleet, or not enough shipyards, or whatever.
But broadly speaking, it takes twice as much 'effort' for your empire to repair the Dreadnought (having already defeated it!) as it would to simply build an equivalent tonnage of ships from scratch. Granted, Metallurgists and Researchers are not directly interchangeable due to different district types and upkeeps. With my current bonuses, that's 6K alloys, so more than twice the value of the ship. Now suppose instead you had 800 extra Metallurgist-months of alloys. So the project costs about 800 Researcher-months of science. At this stage my Researchers make a bit over 30 science each (not all Engineering of course, but I'll assume for simplicity that the three kinds of science are of comparable value). Let's say you have +100% research speed, so you're effectively paying 25K of Engineering production. The cost of the project is 50K Engineering. Overall, if a Caravan came by and offered to sell me a Dreadnought for alloys, I'd be prepared to pay 2K-3K alloys for it your mileage may vary, depends on game stage and so on, but I want to talk economic investment here.
The only special property it has is extremely thick shields, so I suppose it can tank for other ships to some extent.
Frostpunk dreadnought upgrade#
Also you can't upgrade it to a proper Titan AFAIK because it's in a special 'Dreadnought' class. unlike a Titan, it has no aura or special weapons). You basically get a Titan-sized Battleship (i.e. I did this project recently to see what would come out of it, and was a little disappointed, so I decided to do a little maths on the project.