Sheldrake wrote:Gosh where do I start to answer this?
My advice is start by asking why.
Sheldrake wrote:The point about large calibre shells is that they create big shock effects. They are just the job for demolishing bunkers and killing their occupants.
They are not the ideal vehicle for delivering lots of little fragments
True or false: Larger shells have more (and/or larger) fragments than smaller shells.
I'll answer this one for you: True.
More importantly, the WW2 British Army can answer that for you:
Using a standard target of 'men crouching in (British standard) slit trenches', a reasonable approximation of relative effect was the square root of the weight of explosive filling. Of course this ignores the different power of different explosives and this type of target is one that is little affected by fragments. However, it is a representative target for an army on the offensive. It also has logic, a splinter of a given size goes much the same distance no matter what size shell it came from unless there are very significant differences in the HE detonation velocity. However, at any given distance from the burst there will be a greater density of fragments from a larger shell but this density decreases geometrically with distance.
So as I said, fragmentation effect of larger shells is greater but not line with their larger weight, which is one reason why you wouldn't use (normally) heavier shells for a smaller shell's job.
Perhaps it wasn't yours to wonder why but it's never too late.
Sheldrake wrote:and 15 ft is lower than the optimum height of burst for an HE round. Proximity fuzes are set for 10m
I didn't say it was optimal; I said 15ft is better than 0ft and might be feasible. But maybe we can reach 10m with a more extensive telescope system.
10m ideal burst height might be another case on which to ask why instead of to give a rule of thumb. Larger shells' more and larger fragments will have greater ballistic carrying power and greater envelope of casualty infliction. It seems likely that air burst height increases with shell size, though perhaps not across the range of shells that a typical artillerist would need to wonder about.
Sheldrake wrote:This is the 6 inch shrapnel round that could be fired by a 6 inch gun of the type usually found on cruisers.
No idea how shrapnel shells got into this discussion.
Sheldrake wrote:airburst HE is rubbish at dealing with troops sheltering under as little as 18 inches of overhead cover.
With a 16in shell bursting at 15ft anything lightly covered below - a ways around as well - still gets killed by overpressure.
Sheldrake wrote:Battleships have a limited ammunition supply - C 100 rounds on board. Resupply tends to be complicated. Off the Norman coast, battleships needed to return to Portsmouth.
All logistics can complicated, some complicated things are more complicated than other complicated things.
Sheldrake wrote:Barrels have a limited wear life.
All do. A USN 16in/50 firing with reduced charge (max range 27,350 yards) has a barrel life of >3,000 rounds
Sheldrake wrote:A few battleships may have far more firepower than say a divisional artillery group, but lacks the flexibility and granularity to provide comparable support.
False choice. You have the battleships already, we're just discussing their best use.
Sheldrake wrote:In Normandy, with its famously shallow beach head, by D+40 most of the fighting was beyond the range of even the biggest warships.
IIRC some important stuff happened between D and D+40.