But that was the point I was making - they had not got the knowledge and skills base. There was nothing to work with. Any Northern crafttsmen - and they were quite a few - had 'disappeared' on sessession. The local men had volunteered for service and were off. The major sea ports were under blockade and all that was left was the riverside yards - including a number built up from scratch. As for design, most were based on the Crimean floating batteries of Sevastopol, mainly bcaue there was little room for manoever on rivers - even the Mississippi. A turning circle was generally in the order of 500 yards or more. (It is also why tugs and ferries often kept their sidewheels - most could contra-rotate and turn the boat around almost on the spot!)
If iron plate was not available anything would do from rails to heavy timber to cotton bales - they were better than nothing. The hulls were generally unarmored since they were low freeboard wooden hulls, often with very shallow draft due to their river use. That is also the main reason they were given rams - the bow is the stongest point.
Oh dear, where do I start ?
You basically ignored my whole post. The CSN yards DID have the knowledge and skills, what went missing was the white labour force which had volunteered, been commandeered by the army - or in some cases ran off.
There were a minor number of inland yards created from nothing, but they had a nucleus of men who knew river craft.
CSN ironclads WERE NOT BASED ON CRIMEAN FLOATING BATTERIES, and no such proposal was ever made or if it was I have not been able to locate it.
The designs that incorporated an armoured knuckle naturally ended in a projection at both ends, which could be used as a ram. It was not designed as such. However this was not universal and all Constructors produced designs without rams, some of which were under construction or completed.
William Grave's designs had a knuckle and a ram which was part of the hull, not added.
Designs which incorporated the "Pearce" knuckle had bows and stern which were above water, and therefore not rams.
Neither the 1846 nor the 1861 plans by John L Porter had a ram and neither did John M Brooke's Plan (on Which CSS Virginia was based ). I do not know who suggested or made the ram for CSS Virginia, and we do not know what it looked like, despite various purported depictions, merely that it was attached to the stem post.
All purpose designed ironclads had waterline protection as did iron protected vessels such as the Morgan type with a central citadel, and CSS Selma.
River boat conversions were given strengthened bows specifically for ramming, they had no protection below the waterline, what protection they were given was over engines and machinery and sometimes formed a casemate in which guns were mounted. Such protection was usually a combination of thin plate iron, thick timbers, or compressed cotton bales, and as time went on the builders got quite creative, culminating in CSS Webb.