The Portsmouth defences were based on the so-called German or Prussian system of fortification. This entailed a system of interdependent Forts which could combine fire and assist each other in their own defence. Put simply, Fort Widley, whilst an independent Fort in its own right, was also able to rely on the two flanking Forts either side to defend itself. Any attacker assaulting Fort Widley would have come under short-range fire from Widley itself, but would equally have been within range of the heavier weapons from the two flanking Forts. This system of mutual defence and interlocked killing zones was vital to the entire system surrounding Portsmouth. Theoretically, to punch a hole in the Portsdown defences, the enemy would have had to attack and capture three Forts to ensure that they could not be counter-attacked.
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Another feature of this system was the design of the Forts themselves. With straight sides and unforgiving angles creating killing zones in and around the Forts themselves, the system gave rise to the term polygonal fortification.
Here we can see one of those straight sides, rising up from the defensive ditch. As with Fort Brockhurst, note the grass top of the Fort. The second picture here shows an interesting feature, evidence of a Mortar Battery hidden within the Fort. Note the horizontal dark line in the centre of the picture. We shall examine this type of feature more closely in part three.
Note here the steep descending angle of the defensive ditch. This was a formidable obstacle…
…and made even more so by the presence of the Caponiers, gun emplacement that jut out into the centre of the ditch to keep the sides of the Fort clear of attackers. Guns and riflemen would have filled the Caponiers at the first sign of an incursion by enemy troops into the ditch, and the unforgiving straight sides of the Fort would have made picking them off a relatively simple task.
As you will see from these examples, the ditch was very wide indeed, which meant that invading troops would have had to cover lots of open ground to reach their objective.
As we come full circle around to the front of the Fort, we see the end of the defensive ditch as it rises up to the entrance ramps.
In my next article, I will cover another of the Forts atop Portsdown Hill, Fort Nelson, and illustrate how these Fortresses were constructed internally, and how the men assigned to them would have lived and fought. I hope you will join me then.
Links:
Palmerston Forts Society
PFS fact sheet on Fort Widley (.PDF file)
German System of Fortification
To view the complete set of images from my visit, go to the ACG image gallery here.
Discuss this article in our Forums here.
A J Summersgill
andrew@armchairgeneral.com
