I run a 100 amp alternator off my main engine for welding.It also runs all my power tools. Needs to go fast . I use a 10 inch pulley on my engine. I have built everything from wood stoves to anchor winches to self steering, in my cockpit, while at anchor.The welding rig cost me under $50.A couple of points - Can you weld and do you have the equipment for it? I regard that as an essential skill for anyone owning a steel boat. Second is - are you actually going offshore? A steelers performance in most local coastal sailing conditions is generally somewhat compromised by the weight issue. I've never seen one perform like a typical glass boat in those conditions.
If you are actually going offshore steel has a lot of benefits to my mind - the strength and watertightness would give a lot of peace of mind, especially when things go bump in the night.
Brent Swain has a lot of good, experience based info - if you can get past his belligerent fanaticism.
Further, about testing and quality control. I have read anecdotes of how fibreglass yacht outfits on the verge of bankruptcy in the 70's and 80's had unskilled labourers spraying and laying the hulls up, anything to get them out the door cheap and fast. With the price of resin going up fast (oil crisis of the early 1970s) there was a lot of economic pressure to get it done and out the door with as little material cost as possible. Yes, a lot of those boats sailed for a while, but, that era left a real stain on the reputation of fibreglass. Even if one buys a boat originally made by a financially solvent builder who valued not making crap hulls, and never used a chopper spray gun, what was the quality control? What kept the material defects out? Constant human vigilance as the laminate was made. There is nothing more fallible. Once it was laminated, there was no economical way to go back and make sure it was right, no way to detect "good enough for Friday" work when the constant vigilance turned their back for a moment. Did they ever scrap a hull that failed quality control? What did they do with hulls that did not meet their standards? Perhaps they laid in more fibreglass and made a slightly heavier boat that met their standards. There are worse things, like just installing the interior panelling and sticking a price tag on it.