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T2, R1, Prng 39: British Bomb Vessel vs French Bomb Vessel

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  • T2, R1, Prng 39: British Bomb Vessel vs French Bomb Vessel

    In your opinion, which of these two warship types was most significant, influential and/or effective?
    Feel free to apply those criteria as you please, along with any others you think appropriate.
    Note: Suggestions for some additional criteria are at the foot of this post.

    According to the criteria as you see and apply them, please vote for your preferred candidate in the attached poll.
    If your chosen criteria are significantly different from those suggested, telling us what they are and why you used them would be helpful.

    58: British Bomb Vessel 1701-1860

    The bomb vessel, or bomb ketch, was a French development of the 1660's.
    The concept was picked up fairly quickly by some other naval powers; notably the British. The idea was to have a relatively small and maneuverable warship with a modified sail plan, that would provide enough clearance for a mortar or mortars to be installed and fired without damage to the ships masts, sails or rigging.
    The concept was mainly for use against land targets; to bombard enemies into submission. Effectively then, the bomb vessel was a kind of floating artillery and a number of them together would constitute the naval equivalent of a battery. They could also be provided with light armaments for a modest amount of close-in protection if enemy ships were encountered; but this kind of contact was obviously best avoided if possible. An area of sea, river, etc would be made secure against attacking ships by one's own warships and then your bomb vessels could go to work on the enemy's land fortifications, gun emplacements, town, installations, or whatever.
    Bomb vessels had to have a strongly reinforced hull structure, especially around and under the mortars, to absorb the heavy recoil forces. Otherwise (as was found with the earliest attempts), it would not take long for the ship to be shaken apart.

    Our first picture is of a model of the bomb vessel Granado, 1756, showing its overall configuration.
    Typically with this general type of warship, one or two large mortars would be set up on the forward portion of the main deck; and the British - as well as the French - certainly did use that configuration.
    However, so that we can see more than one major variation here, Granado is an example of the most common alternative layout that was found to be workable:
    One of its two heavy mortars was set forward and the other slightly to rear of hull center, between the two masts.
    Bomb vessels usually had two masts only; the "foremast" effectively being the main and set far enough back to accommodate - and allow adequate working clearance for - the mortar or mortars in the front portion of the hull.
    In most cases, relatively light secondary armament consisting of small cannon was carried on conventional trucks, frequently supplemented with "swivel guns" (small anti-personnel weapons on a type of pintle mount).
    Distribution of the secondary weapons along the length of the hull varied, depending on the positioning of the heavy mortars.

    Granado 1756 model overall view front 3qtr.jpg

    Another model of Granado providing a close-up view of the forward 13 inch mortar. The center-mounted weapon was a 10 inch.
    Both mortars were set up on traversable mountings. The main consideration was to be able to offer a usable range of elevation and traverse, while avoiding damage to one's own masts and rigging.
    Due to the layout and weapon distribution used on Granado, the working arcs of the centre-mounted mortar were considerably narrower than those of the forward-mounted weapon shown here.
    On the upside, weight distribution was somewhat easier to balance out than if both main weapons were mounted forward of the masts. This contrasts somewhat with the layout shown below on the French example.

    Granado 1756 model mortar 3.jpg

    Both the British and the French, as well as some other nations, used bomb vessels quite extensively. Accuracy was highly variable and as such, they were often used as "area weapons". Results could still be fairly uncertain so they were far from always successful in achieving the desired aims. An example of this would be the British bombardment of Fort McHenry in September 1814, during the War of 1812. Though undoubtedly frightening for those on the receiving end, it wasn't very effective.

    British bombardment of the American Fort McHenry, September 1814.

    Bombardment of Fort McHenry 1814.jpg

    67: French Bomb Vessel 1601-1860

    As mentioned above, sailing bomb vessels, as such, were a French development. Often they were based on a type of small sailing ship called a ketch. A typical ketch was a two-masted vessel which did not require as much modification as a 3-masted type, to accommodate the main armament. This made them a favored choice for conversion. Therefore, the term "Bomb Ketch" is commonly encountered.
    (Note: If you open the linked wiki article below, scroll down to the lower half for the historical section. The last illustration right at the bottom shows a square-rigged ketch. These were the general type favored for conversion.)

    The French had originally developed these vessels to bombard enemy targets on the Barbary Coast of North Africa. This was part of an effort - shared by many of the maritime powers - to subdue the activities of the Barbary Pirates or Corsairs, which had been a serious problem for centuries. Inevitably, they were also put to good use elsewhere.

    Bomb ketches and other small sailing vessels equipped for the same purpose, could be a bit more challenging to sail compared to a standard version. This was due to the weight of the mortars (typically concentrated near the front of the vessel) and at least a little re-arrangement of the sail plan and rigging that was necessary in most cases. Some attempts were made to distribute the mortars more evenly along the length of bomb vessels (as per the British example above) but these solutions had drawbacks too; not least of which was greater restriction on the firing angles for one or more of the weapons. So, it was a case of "win on the roundabouts and lose on the swings", so to speak, and compromise was inevitable. Nevertheless, the benefits of such a useful vessel were such that it was considered worthwhile.

    The bomb vessel Salamandre is an excellent example of the type and fortunately, enough information is available to get a fair idea of how well it should have functioned as well as for the building of accurate models. All three illustrations are of the same vessel; the second two being accurate scale models:

    Painting of French bomb ketch Salamandre, 1752

    Bomb vessel Salamandre 1752 1024px.jpg

    Accurate scale model of Salamandre's hull, showing the general layout and configuration.
    Salamandre had what may be regarded as the more "conventional" bomb vessel layout, with both mortars forward of the masts in the front portion of the hull. While this presented a certain degree of challenge regarding weight distribution, it was certainly a better solution when it came to the usability of the full main armament.

    Bomb vessel Salamandre 1752 model 1b.jpg

    "Look down" view of the model, showing the structure of the forward portion of Salamandre's deck.
    Two equal size mortars were mounted here but one has been removed for the photo, to show part of the heavy timber supporting platform. Additional stout vertical members lower down, braced into the main hull framework (not visible here), further supported this platform structure and helped to distribute the recoil shock of these weapons.

    Bomb vessel Salamandre 1752 model 1g.jpg

    OK, time to ketch your breath and make a decision:
    Will your vote go to the British bomb vessel or the French?

    Suggested additional criteria you might wish to consider, along with any others you deem appropriate.
    (Note: Some of these could be considered already covered by Significant, Influential and Effective)

    Which warship type ...
    • was the best?
    • was the greatest?
    • was the most widely used?
    • had the greatest longevity in service?
    • was the most versatile?
    • represented the best value for the cost/effort invested ("bang for the buck" in today's language)?
    • was the easiest to operate?
    Any other criteria you have applied (please tell us what they were).
    British Bomb Vessel 1701-1860
    French Bomb Vessel 1601-1860
    Last edited by panther3485; 27 Aug 18, 07:19.
    "Chatfield, there seems to be something wrong with our bloody ships today!"
    Vice Admiral Beatty to Flag Captain Chatfield; Battle of Jutland, 31 May - 1 June, 1916.

  • #2
    Made my vote for the last but saw little in the types to get very enthusiastic about. lcm1
    'By Horse by Tram'.

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


    • #3
      The reason for the issue at Fort McHenry was not an inherent inaccuracy of the mortars. They could be extremely accurate at their normal range. The problem was that the waters near the fort were too shallow for Cochrane to bring his large ships close so that their heavy guns could suppress those of the fort's. The bomb and rocket vessels therefore had to fire at the very limit of their range so as to stay out of reach of the fort's heavy guns. At that range not only can wind forces have a significant effect but the fall of the bombs could not be well observed and adjustments made.
      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)


      • #4
        Mark V, thanks for that information; and yes, it does make perfect sense. Range would have to be one of the obvious factors impacting on accuracy. Further, I would - for example - imagine that conditions on the waters (from which a bomb vessel was firing) could also impact on accuracy if they were not calm?
        (Not saying this was necessarily applicable to the Fort McHenry battle in particular; just another thought that occurred to me regarding a few variables that could affect the accuracy of ship-mounted mortars in general, when I wrote my opening post.)

        Anyway, I'll look at making an appropriate adjustment for the next round ... if the British bomb vessel gets past Round 1.
        Last edited by panther3485; 27 Aug 18, 08:47.
        "Chatfield, there seems to be something wrong with our bloody ships today!"
        Vice Admiral Beatty to Flag Captain Chatfield; Battle of Jutland, 31 May - 1 June, 1916.


        • #5
          Tidal effects also had to be taken into account as during an engagement the difference between the height from which the mortar was being fired and that of a land target would keep changing and had to be taken into account.Most RN use of bombs during the Napoleonic period was in the Mediterranean and Black Sea where tides would not be an issue. One wonders if this lack of experience also had an effect at Fort McHenry.

          The mortars were normally fired at a fixed 45 degree elevation and range was adjusted by altering the charge. The fuse would also have to be adjusted to ensure that the bomb exploded as close to impact as possible. .Rigorous safety measures were in place on British bomb vessels including the inflexible rule that fuses could only be cut and inserted in shells by a senior lieutenant (usually the captain) and in no other place than the captain’s cabin. In the RN a bomb ketch was a lieutenant's command. Fuses were boxwood plugs drilled out to contain a powder core and burning time was adjusted by cutting them to length with a sharp knife. Burn times were marked on a scale on the outside of the plug but there was usually some variability between batches of fuses and some ranging shots would be needed to get it right. One reason why being able to observe the fall of the bomb was so important

          The basic explosive shell or bomb consisted of a hollow iron ball packed with gunpowder into which had been inserted a fuse. Early explosive shell was dangerous to use, far more so than modern munitions. It was also far less damaging to the target than current shells (although if you were standing beside one when it went off you wouldn’t notice the difference)..To obtain maximum effect early shells had to have a large diameter. Mortars typically fired a 10 or 13 inch shell (250 mm to 325mm). The overall weight of the mortar was kept down by chambering so that the propellant charge was surrounded by thick metal but the section containing the shell could be lighter thus allowing a larger calibre.A major problem with the early mortars (and hence danger) was a misunderstanding as to the optimum way to light the fuse on the shell. Originally one gunner would reach into the mouth of the mortar with a lighted port fire and ignite the shell fuse. He would then step smartly back whilst his colleague fired the mortar. Of course if the mortar misfired (damp powder perhaps) the gun crew would be left with a large shell fizzing away and about to explode. This could be an embarrassment but probably not for long. It then became the practice to do away with the two stage ignition process. The shell would be loaded with the fuse facing the charge so that the flash from the charge would ignite the fuse as it sent it on its way. Unfortunately the force of the explosion could on occasion force the fuse deeper into the shell causing it to explode prematurely, sometimes just as it was leaving the muzzle. Around about 1700 it was discovered that none of this was necessary, the flash when the gun was fired sent a wash of flame right around the shell and would ignite the fuse even if loaded facing away from the charge.
          Last edited by MarkV; 27 Aug 18, 09:51.
          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)


          • #6
            Thanks. Some excellent additional information there; much of which I had not as yet acquired.
            Your contributions are greatly appreciated.
            "Chatfield, there seems to be something wrong with our bloody ships today!"
            Vice Admiral Beatty to Flag Captain Chatfield; Battle of Jutland, 31 May - 1 June, 1916.


            • #7
              I like the French Design.

              Pruitt, you are truly an expert! Kelt06

              Have you been struck by the jawbone of an ASS lately?

              by Khepesh "This is the logic of Pruitt"


              • #8
                As another member has commented, not really much to choose between these two but I went for the French mainly because they pioneered this idea.
                "Chatfield, there seems to be something wrong with our bloody ships today!"
                Vice Admiral Beatty to Flag Captain Chatfield; Battle of Jutland, 31 May - 1 June, 1916.


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