rebelatsea
Captain
- Joined
- Mar 30, 2013
- Location
- Kent ,England.
Unfortunately J. L. Porter or his draughtsmen had a problem with weights, Virginia wasn't the only one they got wrong.
Just for fun, from the 1991 Turner TV movie, "Ironclads":
View attachment 24048
Having the fore and aft hull submerged is further reason why Virginia would not have been fit for the open ocean. If she were pitching, each end in turn would go under water and then try to rise against the weight of the water, imposing considerable strain on the hull and likely leading to hogging or leakage. The flat surface is the worst for draining water off. The bow bulwark might make things worse in this situation by making it harder for water to drain off the deck.
I should perhaps have added that his major mistake with Virginia as that he forgot to compensate for the weight of sailing rig and stores, that's why she was light, and the reason for the extra ballast. Hindsight says that should have been used for extra protection.To be fair to him , a lot of plans credited to him were actually by his draughtsman, and some didn't get to him ,although he was supposed to see every plan authorised. He was here, there and everywhere, and maybe he signed some plans that weren't right in the process.
I've been thinking about that as well Andy. I am coming round to agreeing with you, ( about the Virginia that is, my car wouldn't take a hot tub !) and will alter my drawings accordingly..This is why I believe, in the absence of a firm answer either way, that the built-up cutwater on the bow would have been decked over. It would add little additional weight, unlike keeping it open where it would fill with water that could not be drained quickly enough. Like driving around with a full hot tub strapped to the hood of your car.
True, at least some of it could have been used for extra protection as the missing weight (mast and sails) was high up. I don't think a true GZ curve exists, though, since the method was pretty much invented in the mid-1860s in Britain IIRC (with Captain one of the first to be tested).I should perhaps have added that his major mistake with Virginia as that he forgot to compensate for the weight of sailing rig and stores, that's why she was light, and the reason for the extra ballast. Hindsight says that should have been used for extra protection.
True, at least some of it could have been used for extra protection as the missing weight (mast and sails) was high up. I don't think a true GZ curve exists, though, since the method was pretty much invented in the mid-1860s in Britain IIRC (with Captain one of the first to be tested).
OTOH it's also mentioned that the ballast was needed for stability.
It looks like post-Hampton she had three hundred tons of ballast in her. A waterline belt below the 'shield' would have been very roughly 650 feet long, and 100 tons of ballasting being changed to a waterline belt would allow for about four inches of armour thickness (four layers of 40lb plate) two feet high.
That combination would have made her both more able to accept different load conditions (thus increasing tactical flexibility) and generally safer in combat. 40lb plate is also comparatively available.
For the rest of the ballasting I'd probably prefer to put extra cannonballs in! That was a big problem at the historical Hampton Roads, she didn't have enough cannonballs for two days of fighting as she expended most of them as e.g. hot-shot on the first day and was reduced to shell.
Well, I underestimated naval nerds. Someone did a full analysis of Virginia including several GZ curves:I don't think a true GZ curve exists, though, since the method was pretty much invented in the mid-1860s in Britain IIRC (with Captain one of the first to be tested).
Thanks for that, I'd not seen that before. Certainly if her gunport covers had been stoppers that would be true, but I'm not sure they were, in fact I don't think any CSN ironclad had port stoppers, except perhaps Mississippi, and the reference is vague on that. effectively Virginia's hurricane deck was not seatight -or even waterproof !Well, I underestimated naval nerds. Someone did a full analysis of Virginia including several GZ curves:
https://vtechworks.lib.vt.edu/bitstream/handle/10919/74944/Marickovich_NE_T_2017.pdf?sequence=3
(Curves are on numbered page 56 onwards)
What's interesting about the analysis is that it suggests that the centre of gravity position is very important and that the ballasting may indeed have been necessary. On the other hand, Captain's GZ curve has maximum righting lever of 20cm at 15 degrees and Virginia's worst-case is about the same - and Captain was literally blown over by a dynamic sail load, so perhaps Virginia would have been okay in sheltered water and without sails.
One other nifty point raised is that the immersion of the gun ports (if closed) may not have been fatal, but the immersion of the inclined armour deck would have been owing to the armour structure as cross-hatched rail ties instead of single strake.