Poiuytrewq wrote:It would be more like £860m a hull or £1.72bn if you drop back to six T26's.
I think you ignore design+initial cost. If you see FREMM wiki, you can find it. It is based on some French senate answer.
(But I cannot read .... )http://www.senat.fr/rap/a14-110-8/a14-1 ... tml#toc308
Ignoring design+initial, a 2nd-tier frigate option becomes attractive. But, design+initial cost is huge...
Ron5 wrote:1. Not sure what size has to do with Leanders electric propulsion. Far larger ships are diesel electric.
Sorry you are right. The Leaner small size merit is on "can do with 2 diesel". And, it is "in-directly" cause the need for electric drive (for low speed operation) and so on so on..... But, yes no directly related ...
2. Electric propulsion does not confer silence in itself. Diesel generators are still running and in Leander, the electric motors drive the shafts through large gearboxes. Both, if not silenced, will produce plenty of noise.
You are right. At the same time, there are many "silent rafted diesel gensets". With no mechanical shaft connected, quietization becomes very very easy (of course not for free). Gearbox is also important, but for example, FREMM is using quietezed gear box. Interesting that it is considered cheaper than "co-axial" motor option.
3. We had the discussion many times before. I don't believe the size or type of sonar can overcome a noisy ship. It's about signal to noise ratio.
4. Did the French really make that trade off or are we just speculating?
It is claimed by DCNS guy when FTI and CAPTAS4CI was introduced.
Yes, it is signal to noise ratio. In case of passive ASW, yes, hull quietness is the only option. In active ASW tactics, if you increase signal, you can overcome noise (to some extent).
- Increasing signal = 4-barrel VDS (CAPTAS-4 and 4CI) is twice better than CAPTAS-2.
- Increasing signal = Because active ASW's "detection range" is proportional to "(power/noise)**(1/4)", if purely about the range, more hull might be better, depending on the tactics and (power/noise) ratio.