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Note on the Speed of Merchant Ships

The Hon. Editor has suggested that in connection with my remarks on the protection of shipping I should add a note on speed in relation to new mercantile construction. While fully recognizing the protection which in itself increased speed would afford I do not feel able to come to a final conclusion on this subject although I have endeavoured to follow the arguments. We have got to get a great number of new merchant ships as quickly as possible. If they can be built just as quickly with high speed as with low, then the increased cost involved in high speed .should not be allowed to affect the decision. The State should find the money because we can lose the war on the shipping factor, and expense must not be allowed to count. And if higher speed means better protection we must remember that we have to protect not only ships and cargoes but also seamen's lives. If, however, higher speed means slower construction, a very arguable problem is opened up because we cannot afford delay. The fast cargo ship takes longer to build and carries less cargo, as well as making heavy demands upon building berths, engine production capacity and fuel. The arguments are very varied. I have seen it advocated that we should build five fast 2,000-ton ships with bulkhead sub-divisions in preference to one slow one of 10,000 tons with undivided hull, so that it is not only fast ships versus slow that is under discussion, but also large ships versus small. The urgent thing is to build the type of ship most useful for winning the war, but uttering that resounding platitude gets us no nearer to deciding what that type is. The disadvantages and dangers of slow ships sailing in large, slow convoys easily sighted by aircraft and open to attack by U-boats of much higher speed, need not be stressed. One thing is certain: post-war considerations must not be allowed in any way whatsoever to affect the issue as to what we build to-day when the essential problem is to get maximum use of time, labour and materials while not overlooking the necessity for saving ships and seamen's lives. In this connection the First Lord has recently stated that: "single-screw standard ships of 10,000 tons dead­weight and speed of 11 to 12 knots are the most economical in material, man-power and carrying capacity." This statement leaves the question of safety of men and ships out of account, but in other respects seems final. Officers and men of the Merchant Navy certainly express themselves in strong language concerning their experiences in slow ships. In fact, a certain number of the ships building to-day are of the fast cargo type.

It may be noted that before they entered the war the United States had no ocean-going merchant ship building of less than 15 knots speed. She is now concentrating on ships of 11 to 12 knots.

Another point of interest is that head winds affect a slow ship much more than a fast one, and the ratio of average sea speed of the faster to the slower ship is far greater than the ratio of smooth water speeds. So much is this the case that in certain oceans a slow ship can only operate in winter during good weather and in bad becomes a sitting target. All this bears upon a war problem of prime importance, viz. the rate of delivery of goods which depends upon time of voyage. But if all our plans are laid out on the basis of the slower type of ship being built, then to switch over to a faster type would obviously involve an interruption of programme and serious delays.

The ship of 15 to 16 knots is reasonably immune from a U-boat's torpedo attack and can shoot out a surface attack by gunfire with the advantage on her side. She would consume about three times as much fuel as the 10-knot ship, and so possibly be at a disadvantage in the post-war competitive world. With a view to having your cake and eating it, a suggestion has been made to engine ships with a central and two wing sets of machinery, the central set giving 10 knots and all three together 15 knots. The two wing sets could be removed after the war, setting the space they occupied free for cargo.

As regards a fast ship carrying less cargo, one well-known authority asserts that a 15-knot ship could be designed to carry as much cargo as one of 10 knots. There is also the point of whether a convoy of 15S-knot ships would require as much warship escort as one of 10 knots.

I hope these imperfect notes may provoke some comments which will go far to settle this very moot but urgent point. .

W.