Hi Folks: It seems to me that y'all may be overlooking one important factor here, namely that no two vessels--no matter how identical they were when commissioned--remained that way for long. Their commanders routinely made modifications and added or removed elements that they felt improved the ship's performance. Therefore, I agree with David that the fact that one of the Tennessee's crew specifically mentioned the interior netting is proof enough that it was used on that vessel. However, that doesn't mean that such netting was used (or not used) on other ironclads.

As far as the Rotterdam folks' opinions go; I would be inclined to agree (in part) since I can't recall any mention of wood backing inside a TURRET, hence, no need for splinter netting. However, we can't apply the example of a turreted vessel to casemated vessels like the Tennessee, which comprised the majority of the Confederate ironclads. For that matter, did the Reb Navy even have any turreted vessels?

At any rate, I did find the following mentions of splinter netting in the ORN as follows:

Vol 11, Pg. 670: After-action report of CSS Virginia (II):
'...the Virginia was struck upward of 70 times, many of them blows from the heaviest rifle projectiles and 2 from the monitor; one of the latter, probably a XV-inch solid shot, and another, a rifle 200-pounder; the effect of the last two broke and crushed in the iron, the wooden backing, clamp, stanchions on port side of shield, and on the port quarter made a hole entirely through, 2 feet by 2½ in diameter. The splinter netting no doubt prevented many casualties, only 1 being killed and 2 wounded.'

Vol 18, pg. 199: After-action report of USS Richmond:
'Much injury to the men, I am sure, was saved by a carefully prepared splinter netting. At one point between the guns the netting was forced out to its utmost tension; indeed, large pieces of plank were thus saved from sweeping the deck and perhaps destroying the men at the guns...'

On the subject of fastening; Since the sides of Tennessee's casemate were angled inward, it is almost certain that the netting would have been fastened to the casemate backing at the bottom. Otherwise it would have hung down like a curtain which would have presented serious difficulties when loading and training the guns. This would seem to be confirmed by the use of the word 'tension' in the Richmond's report, above. In order for tension to have existed, the netting would have to have been fastened to the bulwark either on both sides of, or above and below (which makes more sense), the bulge caused by the shell impact.

Also in the same report, the phrase 'carefully prepared splinter netting' leads me to suspect that these nettings were not simply large-mesh boarding nets. It's likely though that they were made from boarding nets by weaving in additional rope strands at regular intervals to create a smaller mesh, thus providing added strength and protection against smaller splinters.

And, speaking of splinters; I remember seeing at least one report of a 'splinter' that measured roughly 2 feet long and 3 inches in width, so we're not talking about the little slivers that we commonly remove with tweezers.

I doubt, though, that there was any netting on the ceiling since they would only have been necessary to protect from plunging shots fired from a higher elevation ,i.e. fort or mortar, neither of which she was likely to encounter in her anticipated theatre of operations.

On to the subject of wood backing. As early as April of 1863, at least some in the Union Navy had learned that the combination of wood and iron--at least on flat-sided casemates--provided more protection against penetration than iron alone. Although iron is very hard, it is also very brittle and tended to shatter under the impact of a heavy shell. Adm. D. D. Porter discussed this principle somewhere (sorry, I just didn't feel like looking up the source) and mentioned that, in light of this fact, he had the commanders of the Union ironclads lash logs to the port and aft sides of their casemates for the run past the batteries at Vicksburg. And as someone pointed out, mounting at least one layer of wood backing diagonnaly would dissipate the force of an impact across more area and framework. And I seem to recall that at least one Confederate ironclad (CSS Arkansas or Missiouri I think) had courses of railroad iron mounted diagonally on her casemate.

Sorry for the long post guys.