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Appendix No. 4.
JAMAICA.
Port Royal Point battery.
Gun in Prince of Wales' line.
368
25. A circle drawn from the dockyard with a radius of 7,300 yards just cuts the reefs outside from Half-Moon Bay right round to Plum Point.
the
26. No bombardment ought to be possible, even by iron-clads, within a range of 8,000 yards of guns which we shall shortly possess. Even to gain that range, the enemy would have to lie close outside, and to windward of very dangerous reefs, evidently a position of extreme peril, and one which would probably lead to the loss of any ship which was injured in her machinery by the fire from the forts.
27. With new guns of great range and accuracy, mounted in advanced batteries, a squadron would be kept at such a distance that their bombarding fire would have no effect. The chief impor- tance of Port Royal is in its being a secure coaling depôt. A coal-shed would probably not suffer much injury from a bombardment. The dockyard offers an exceedingly small mark in any case, and more- over, stands at right angles to the probable direction of fire, which diminishes the chances of injury
still more.
28. To carry out the changes in the nature and armament of all the batteries, as proposed in the War Office Memorandum,* would necessitate pulling down and reconstructing the works in progress, which would entail a great expense.
29. On the whole, we think the wisest plan would be to complete those of the works under construction which protect the lines of mines, whilst to hold an enemy at a distance at which bom- bardment will be impossible, Little Plum Point and the advanced position near Drunkenman Cay should be occupied with armoured turrets, mounting each two heavy guns.
30. It is essential, in our opinion, that the battery which protects the eastern channel should also be able to take part in the defence of the southern one, and Little Plum Point is the farthest position to the eastward at which this would be possible.
31. By constructing shielded batteries as contemplated in the War Office Memorandum, the area each would cover is necessarily limited, but as all the guns of the advanced defences should be capable of bearing on either channel of approach, they should be mounted in turrets.
32. It will be seen by reference to the plan of the defence facing page 2 of the War Office Memorandum, that the proposed armoured battery on Drunkenman Cay does not bear at all on the eastern channel, and that neither this battery nor that proposed for Little Plum Point, bears on the upper portion of the south channel.
33. It is apparently to remedy this that the Memorandum proposed to construct a heavy battery on Port Royal Point mounting five large and two medium guns, but we consider a battery of this character unnecessary if the batteries at Little Pium Point and Drunkenman Cay have all- round fire.
34. In the opinion of Commander Grenfell, a member of the Committee, the armoured turrets on the Gruson system, adopted by the German Government for the defence of the Weser, and by the Belgian Government for Antwerp, are highly suitable for the defence of Port Royal. Two revolving turrets armed with 10-inch or 11-inch breech-loading rifled guns would cover the whole of the position. They would be compact, self-defensible, as prescribed in the letter of the Royal Commission, possessing a high degree of immunity from attack, and, he believes, might both be built and armed for little more than the cost of the one armoured battery on Drunkenman Cay proposed in the War Office Memorandum.*
35. They also possess a valuable feature for distant places like this, where skilled labour for constructing heavy iron forts is not available. When the masonry foundations are ready, the turret of which the several portions are shipped finished from the manufactory is completed by simply setting the parts together and pouring zinc in the grooves.
36. As the other members of the Committee have no acquaintance with this particular form of turret, they limit themselves to stating that in their opinion all-round fire is an essential feature of the defence, which they think ought to be secured by mounting the heavy guns in turrets; at the same time they consider the advantages which Commander Grenfell informs them the Gruson turrets possess in respect of simplicity of construction, cheapness, and defensive power, such as to make them very suitable for the defences of Port Royal.
37. The total number of guns proposed in the Memorandum, thirty-seven, of which twenty-one are large and powerful guns, seems to us far too great. By a more judicious method of placing them, we are of opinion that four of this class of gun would be ample. These four guns, if mounted in turrets, would bear on the attack during the whole of its approach by either channel. If placed in shielded batteries, it will be evident on referring to the plan in the Memorandum, that in some positions in the eastern channel an approaching enemy would have to deal with only two out of the thirty-seven guns.
38. With the advanced position on Little Plum Point and Drunkenman Cay occupied by guns in turrets, and with guns in Port Royal Point Battery and Prince of Wales' Lines, we fail to see the necessity of any work on Rocky Point. It could only serve to bring a cross-fire on the middle portion of the eastern channel against gun-boats or launches attempting to destroy the torpedo defences, but we think the whole of the ground is amply covered by the other batteries and we are therefore of opinion that the Rocky Point position is unnecessary and should be abandoned.
39. We do not think it necessary to go to the length of placing the costly (30,8517.) permanent obstructions described in the War Office Memorandum. These would only be required in the case of a heavy attack methodically undertaken, and such an attack does not enter into the scope of these considerations. With the knowledge that the system of mining defence was combined with powerful batteries, he would be a rash antagonist who would risk an entry by any other than the two main channels, especially with all the buoys removed or shifted as they would be.
40. It may be added that the main reason given in the War Office Memorandum for placing these obstructions is to secure the advanced battery on Drunkenman Cay from being taken in reverse. This could not occur in the case of a turret.
* No. 110.
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