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  • #61
    Originally posted by T. A. Gardner View Post


    Britain used mostly 9.2" and 6" guns for their main coast defenses.
    I had always wondered about that till I read somewhere that due to the much smaller size of the UK, the coast defenses were secondary to the RN being just around the corner, figuratively speaking.
    Last edited by johns624; 25 Jan 16, 16:28.

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    • #62
      Coastal forts in the period 1900 -1945 were principally a US obsession. Britain relied much more on her naval superiority and in WW1 (and probably WW2) the RN would have gladly issued the German battle fleet invitation tickets to congregate in the North Sea off the British coast where Britain's superior numbers of battle ships could get at them. Raids such as the Hartlepool and Scarborough bombardments were probably seen as a price worth paying if they encouraged the German fleet to come out in force and get slaughtered (my Grandparents who were in Scarborough with my infant father at the time may have thought differently). British coastal defences were much more oriented to dealing with raids in the form of landings and twin 6 inch guns were well suited to dealing with landing ships coming inshore. At the same time the barbette mounted 9.2 breech loaders could fire at a higher elevation than ships guns and thus match the larger guns in range and had power assisted loading so that they could pump out shells faster. Some 9.2s installed near Dover were on high angle mountings to allow them to drop shells on the thinner deck armour of attacking ships. These guns were installed where battleships with flat trajectory fire could not reach them.
      Human history becomes more and more a race between education and catastrophe (H G Wells)
      Mit der Dummheit kaempfen Goetter selbst vergebens (Friedrich von Schiller)

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      • #63
        The umpteen batteries of 9.2 inch around the world (Sydney to Vancouver following the sun) all had a max elev of 15 degs.

        The high angle were 15 in at Dover and Singapore, max elev 45 degs (which technically speaking isn't actually high angle), 8 inch at Dover (70 degs), 6 in BL (45 degs), the rest were mostly 20 degs.

        Proper high angle for coast guns it not a really smart idea, for best chance of a hit on a ship you need the flattest possible terminal trajectory, however, presumably the thinking was to maximise damage with shells going into the hull from above where there was least armour. HA also maximises the time of flight which minimises the rate of fire if you are observing the fall of shot to correct you aim.

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        • #64
          High angle increases range.

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          • #65
            Originally posted by johns624 View Post
            High angle increases range.
            Only up to 45 degrees (1600 mils). Basically max range is achieved with an elevation angle of 45 degrees (give or take a little bit to compensate for non-standard conditions). Once you get over 45 degrees the range starts decreasing. The military definition of high angle fire is an elevation angle greater that 45 degrees.

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            • #66
              Originally posted by johns624 View Post
              I had always wondered about that till I read somewhere that due to the much smaller size of the UK, the coast defenses were secondary to the RN being just around the corner, figuratively speaking.
              That may be. The US thinking was that a gun of equal size to those the coast defenses faced was necessary to take on ships. Hence the use of 12 to 16" guns in major harbors, 8 to 10" guns in secondary locations where engaging cruisers was likely, and the inclusion of 3" to 6" guns for defending minefields against being swept.

              The mortar was included as part of the system to give plunging fire at a time when the engagement range was assumed to be less than 10,000 yards (1900ish). With increasing range these became somewhat obsolescent but did prove very worthwhile as artillery against land forces as they had a 360 degree field of fire and were all but immune to counterbattery or bombing.

              Oh, on US BB, the older ones when modernized had their main battery elevation increased from 15 to 20 degrees to 30 degrees. New construction ships had 40 or 45 degree elevation built in.

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              • #67
                Originally posted by Soothesayer View Post
                The umpteen batteries of 9.2 inch around the world (Sydney to Vancouver following the sun) all had a max elev of 15 degs.

                The high angle were 15 in at Dover and Singapore, max elev 45 degs (which technically speaking isn't actually high angle), 8 inch at Dover (70 degs), 6 in BL (45 degs), the rest were mostly 20 degs.

                Proper high angle for coast guns it not a really smart idea, for best chance of a hit on a ship you need the flattest possible terminal trajectory, however, presumably the thinking was to maximise damage with shells going into the hull from above where there was least armour. HA also maximises the time of flight which minimises the rate of fire if you are observing the fall of shot to correct you aim.
                9.2 BL were installed as follows four guns at Sheerness, three at Harwich, two at Coalhouse (Thames), two at Plymouth, one at Milford Haven. Overseas installations included eight at Bombay, five at Aden, five at Hong Kong, three at Malta, three at Karachi, two at Singapore and one at Halifax. Figures given for range quote two elevations 12.5 and 35 degrees
                Human history becomes more and more a race between education and catastrophe (H G Wells)
                Mit der Dummheit kaempfen Goetter selbst vergebens (Friedrich von Schiller)

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                • #68
                  Originally posted by MarkV View Post
                  Bismark and Tirpitz differed in design from many (most?) Allied battleships in having turrets that allowed elevations of 30 degrees (same as was adopted for Vanguard). This had the advantage of allowing a longer range to be achieved but the disadvantage that the guns had to be lowered fully down for reloading. Hood shared the common disadvantage of other battle-cruisers of having thin deck armour to save weight and allow faster speeds to be achieved, if you combine this with a shell fired from the steeper trajectory possible by Bismark then I think this answers the question.

                  A further limitation of battleships when attacking modern coastal forts was the lack of time fuzes. The big armour piercing shells had to hit something before exploding. If the fort has heavy mortars in pits surrounded by concrete the ship has to score a direct hit on the pit rather than rely on the general spread of splinters etc from an air burst to discommode the gun crew. Not easy from a moving platform from a distance of ten or more miles. Tirpitz for example only had time fuzed shells for her main armament late in the war - this was to allow the big guns to put up an AA barrage.
                  Thank you MV, The majority of my sea going during the war was spent on small L/C and as I have said before you tend to live in your own small World. lcm1
                  'By Horse by Tram'.


                  I was in when they needed 'em,not feeded 'em.
                  " Youuu 'Orrible Lot!"

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                  • #69
                    Originally Posted by MarkV
                    Rather a lack of understanding of the issues of ships taking on forts on your part I think. Warships guns fire on a fairly flat trajectory and have difficulty delivering the plunging fire needed to take out forts' artillery in pits etc. This became particularly evident in the Dardanelles and attempts were even made to mount heavy howitzers on ships, without much success. The issue was long known however and had been evident in some of the actions during the Crimean war. Warships moreover are usually firing from below the level of the top of the fort which adds to their difficulties..
                    This blanket statement is indicative of the lack of understanding of how artillery works.

                    Naval gunfire, in fact, becomes plunging fire at distant engagement ranges, because like any projectile, it's shells are subject to the laws of gravity. Indirect naval gunfire has been in use for a very long time, and was used extensively during the Normandy invasion, firing inland at preregistered targets that were well beyond line of sight.

                    Naval armor neglected decks because in the days of fighting sail and ironclads, engagements were at point blank range, and naval architects failed to understand the new paradigm they were operating within, the necessary loft of the shell to overcome distance. A battleship's main armament can reach up to twenty miles, well beyond the visible horizon and a LONG way beyond "flat trajectory". That is why you never see battleship guns aimed out flat from the sip, but always elevated to whatever degree is necessary to obtain the correct arc and reach the distant target.

                    Plunging fire put an end to a number of fine, otherwise well protected armored vessels, including battleships and Britain's much vaunted "heavy battlecruisers."

                    It is entirely possible for a hit to impact a gun emplacement or a mortar pit. In fact, given the average weight of a main gun round, anywhere up to 2000 pounds of high explosive, a near miss (up to 100 yards under the right circumstances out in the open) will suffice to kill every single member of a gun crew through sheer blast effect, which the human body is horribly vulnerable to. An armor piercing shell of this caliber will make a mockery of a concrete fortification, and the enclosed space will amplify the concussive and blast effects exponentially.
                    \We see what we see in the old emplacements because the "experts" didn't know what they needed to know in order to properly design and build defensive works.

                    Here is an excellent example: during WWII, despite voluminous data on artillery effects up to and including monster caliber guns, bunker construction firms made two basic patterns of casemates, the Army pattern and the Naval pattern. The Army pattern lacked the heavy apron surrounding the bunker, making it cheaper and faster to build, but subsequently was often knocked out by a near miss which knocked it off it's foundation. The Naval pattern, with it's more expensive and labor intensive heavy integral apron, stayed stable and operational. The one million ton bomb proof ferro-concrete dome built to hide a V2 launch site in France was defeated by being knocked off it's foundation without ever being directly struck by a bomb, because no integral stabilizing apron was included in its construction. One learns these things the hard way most of the time.

                    As naval artillery got larger and more technically sophisticated, and more accurate, shore defenses failed to keep up, victims of the "fortress mentality" mindset so common throughout WWII. Even Hitler, who after bypassing the Maginot Line understood completely how useless such fortifications were, devoted himself to building them ever bigger and stronger, and ultimately more useless.
                    Last edited by Mountain Man; 26 Jan 16, 16:55. Reason: too many zeros!!
                    Quis Custodiet Ipsos Custodes? Who is watching the watchers?

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                    • #70
                      "Only a fool attacks a fort" Admiral of the fleet Lord Fisher
                      Human history becomes more and more a race between education and catastrophe (H G Wells)
                      Mit der Dummheit kaempfen Goetter selbst vergebens (Friedrich von Schiller)

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                      • #71
                        Originally posted by MarkV View Post
                        "Only a fool attacks a fort" Admiral of the fleet Lord Fisher
                        There's somebody over in the alt history system that would vehemently disagree with you...

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                        • #72
                          Originally posted by MarkV View Post
                          Coastal forts in the period 1900 -1945 were principally a US obsession.
                          Actually coastal forts were a US obsession from the 1790s-1945.

                          At one time in the early 1800s we had more costal guns than casements to place them, and an average of one crewman per five guns.

                          Some of the earliest pork barrel programs in the USA was buying coastal artillery.
                          Any man can hold his place when the bands play and women throw flowers; it is when the enemy presses close and metal shears through the ranks that one can acertain which are soldiers, and which are not.

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                          • #73
                            New York, Baltimore and the like must have made a serious impression on them.
                            "Artillery lends dignity to what might otherwise be a vulgar brawl." - Frederick the Great

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                            • #74
                              i believe that at least part of the reason for our large coast defenses was our isolationist policy up until WW1. We were primarily concerned with defense, rather than power projection.

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                              • #75
                                The definitive account of UK coast artillery is Maurice-Jones' "The History of Coast Artillery in the British Army". In autumn 1941 there were 11 ports around UK with 9.2. This included Dover, Plymouth and the Solent each with 6 guns. There were a total of 35 9.2 guns around UK.

                                Overseas ports with 9.2 were Jamaica, Gibralter, Malta, Colombo, Singapore & HK.

                                In addition they were 9.2 at Sydney, Newcastle & Rottness Island in Australia,
                                Halifax and Victoria (nr Vancouver) in Canada, and Simonstown in S Africa.

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