SECTIONAL SKETCH of SUNKEN BLOCKSHIPS
In this position the silt was known to be very active. That fact, taken in conjunction with the exposure to rough seas, the presence of the tidal current, and the impracticability of erecting salvage plant on the land within easy reach of the vessel, rendered it obvious that, all things considered, the position between the wooden piers would be the ideal blocking position if suitable vessels were available for the purpose, and if such vessels were damaged and sunk with due regard to anti-salvage considerations.
It is common knowledge that when vessels are fitted out as blockships they usually carry a goodly cargo of cement. The general notion, however, about the use of this material is that it is merely intended to make the ships heavier and thus less capable of being lifted. That is only partially correct. There is another and more important use for cement, namely, as a counter against the use of acetylene gas for cutting the ships to pieces. The general scheme is that of placing the cement in just those positions where cutting would be most necessary; in our case, in those portions of the ship which would be above the lowest level of the tide and up to within six feet of the highest tide level. The depth of our chosen position being twenty-one feet at low water and thirty-six feet at high water, this meant that the cement would need to be placed between the levels of twenty-one feet and thirty feet above the keel, provided that the ship was sunk in an upright position. With regard to the latter proviso, steps must be taken to guard against the eventuality of the ship resting on her beam ends on the sea-bottom as a result of capsizing when foundering. This cautionary measure necessitated placing the cement between the levels of twenty-one feet and thirty feet from her beam ends at either side of the vessel as well as between the same vertical distances from her keel. Nothing should be left to chance that can be provided for in advance.
It was clear enough that the task of ever getting the ships into the desired positions for sinking would be far from simple; having attained that object it would be the height of stupidity to sink the ships in such a manner, and so fitted, that their removal would be comparatively easy.
After the operation had been successfully completed I could not help being rather amused at a certain individual who expressed the opinion that "the Germans are so cute that they'll probably remove the blockships in a day or two." Why were some people always so ready to credit the Germans with everything that's wonderful? The reasons were not far to seek; such ideas arose partly from natural ignorance on technical matters and partly because the Germans never ceased to assure us how marvellous a nation they were. And some of us believed it! Verb. sap.
With all the difficulties in the way of attainment, what counter considerations were there to make the attempt worth the undertaking?