It was stated that the single experiment carried out at Portsmouth was not enough to indicate exactly the best position for the boom, and the first boats to be fitted will probably vary somewhat between having it in the quarter or right aft. The additional weight of the boom is slight; in the case of the _Starfish_, the destroyer experimentally fitted, the weight had been more than compensated for by fitting her with aluminium, instead of the usual torpedo tubes. To say that if a submarine rises anywhere near a destroyer armed with a spar, her destruction is absolutely certain, is, we think, going too far. To blow up a stationary barrel is not a very difficult task, but it must not be forgotten that if the destroyer sights the submarine, the submarine will also sight the destroyer and will endeavour to launch a torpedo at the destroyer before the latter can explode its weapon. Besides this the submarine having sighted the destroyer can dive and make off in a direction which the latter cannot foretell, and there would seem to be a good chance of her escaping. Submarines will probably act in conjunction with torpedo-boats and destroyers, and the object of these vessels will be to ward off the attacks of hostile torpedo-boats and destroyers. It has been said that in action the moral effect of the submarine would probably outweigh its practical effect, and it is now urged that the moral influence of this new antidote to submarines will be very great. “The risks of ordinary submarine work,” says a writer, are not so great as many people imagine; and they can in a great measure be overcome by practice. But the deadly spar will quite alter this. The men in the submarine cannot acquire familiarity with this in peace; not till war will it operate. Then, whenever they are rising, they will know that a destroyer _may_ be within reach, and that, if so, absolute annihilation is _certain_, and annihilation in a particularly horrible form.