- Feb 20, 2020
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You do know I am here right?Who is "we"? And what evidence do you have that anything besides the Neptune/Minotaur and stolen Tzoli pictures you posted are real vessels?
You're right that the larger hull would help, but the problem is not just the weight of the turrets, but their height - the significant factor is their moment arm, so it's weight times height above the waterline. And it isn't just the turrets we have to consider, the fourth superfiring forward turret pushes the bridge and everything above it up at least one deck level compared to the earlier K25 designs with four turrets on three levels. There's a similar effect at the stern, but here it's only the aft director (still a substantial weight) being pushed up a deck level compared to the earlier designs.I think topweight might be a lesser problem on these designs as they only carry a pair of turrets more then a Dido yet on a larger hull
ISTR the shore-based AA/Coastal defence mounts were singles.Interestingly I've never seen a design with single 5,25" mounts or turrets say for a small cruiser or destroyer. (I did see once ages ago a hypothetical carrier model with single 5,25" turrets basically cut in half assymetrical Dido turrets)
Strictly speaking it's height above the centre of buoyancy that matters, which is why weight close to the waterline still causes stability problems.You're right that the larger hull would help, but the problem is not just the weight of the turrets, but their height - the significant factor is their moment arm, so it's weight times height above the waterline.
I couldn't remember metacentric height when I needed it, so went with waterline as sufficient to get the point across. But the actual detail makes the point even better.Strictly speaking it's height above the centre of buoyancy that matters, which is why weight close to the waterline still causes stability problems.
The centre of buoyancy is generally one-third to half the draught below the waterline, but that's a function of the hullform. As is the location of the metacentre, which is also calculated with respect to the centre of buoyancy. Keep the centre of gravity well below the metacentre or else you'll have a bad day at sea!
Because the shape of the immersed hull changes with displacement, weird things can happen sometimes. I've dealt with a barge loading condition where adding topweight actually improved stability by increasing the displaced volume significantly. But that isn't normal, and adding the same weight low down would have an even more beneficial effect.