- Joined
- Aug 25, 2012
When we read the details of Civil War era ships the details include how much the ship weighed, but how did the know the weight of a ship?
Historically, I thought that the weight of ships was determined by its water displacement?When we read the details of Civil War era ships the details include how much the ship weighed, but how did the know the weight of a ship?
They weighted itWhen we read the details of Civil War era ships the details include how much the ship weighed, but how did the know the weight of a ship?
So when I wrote my book on the Southern Iron Navy, out of sheer self defence I evolved a calculation to show relative size in approximate displacement tonnage. This was the result of hours of going through published figures and plans !
Length overall x maximum beam x mean draught, divided by 70 = equals approximate displacement tonnage.
It may not be scientific, but it seems to work well enough .
You calculate the amount of water displaced by the ship and convert that to weight.
Right. It's not the literal weight of the ship in tons of wood, steel, etc. It's the displacement.Historically, I thought that the weight of ships was determined by its water displacement?
One of the things that can make you use colorful language is trying to make sure you understand whether a citation is using overall dimensions. A good example of this problem is trying to make an estimate of the converted displacement of the Manassas. We have some fairly accurate dimensions of her earlier incarnation (Enoch Train), but the addition of the ram and its supports, the hull blisters (were they solid or hollow?), etc, plus an estimate of her ironing and loaded draft (anywhere up to 17 feet). Some of the newspaper accounts of Enoch Train seem to be using dimensions as measured on deck. Then you have the issue of how much of the vessel was above the waterline, so you can estimate the ironing. The only solid number I ever found about this vessel was the weight of a replacement smoke stack put aboard after Head of Passes (1600 lbs).I did something very similar when I put together the stats for my old website. (I did the calculations nearly twenty years back and can't recall the specific formula I used, but my methodology was the same.)