[Footnote 95: Written in 1902. (Read at the Hong-Kong United Service
Institution.)]

A problem which is not an attractive one, but which has to be solved, is to arrange the proper method of supplying a fleet and maintaining its communications. In time of peace as well as in time of war there is a continuous consumption of the articles of various kinds used on board ship, viz. naval stores, ordnance stores, engineers' stores, victualling stores, coal, water, &c. If we know the quantity of each description of stores that a ship can carry, and if we estimate the progressive consumption, we can compute, approximately but accurately enough for practical purposes, the time at which replenishment would be necessary and to what amount it should be made up. As a general rule ships stow about three months' stores and provisions. The amount of coal and engineers' stores, measured in time, depends on the proceedings of the ship, and can only be calculated if we know during what portion of any given period she will be under way. Of course, this can be only roughly estimated. In peace time we know nearly exactly what the expenditure of ammunition within a given length of time—say, a quarter of a year—will be. For war conditions we can only form an estimate based upon assumptions.

The consumption of provisions depends upon the numbers of officers and men, and in war or peace would be much the same. The greater activity to be expected in war would lead to more wear and tear, and consequently to a larger expenditure of naval stores. In peaceful times the quarterly expenditure of ammunition does not vary materially. In case we were at war, a single action might cause us to expend in a few hours as much as half a dozen quarterly peace allowances. There is a certain average number of days that a ship of a particular class is under way in a year, and the difference between that number and 365 is, of course, the measure of the length of time she is at anchor or in harbour. Expenditure of coal and of some important articles of engineers' stores depends on the relation between the time that she is stationary and the time she is under way. It should be particularly noted that the distinction is not between time at anchor and time at sea, but between time at anchor and 'time under way.' If a ship leaves her anchorage to run an engine-trial after refit, or to fire at a target, or to adjust compasses, or to go into dock—she burns more coal than if she remained stationary. These occasions of movement may be counted in with the days in which the ship is at sea, and the total taken as the number of days under way. It may be assumed that altogether these will amount to six or seven a month. In time of war the period under way would probably be much longer, and the time spent in expectation of getting under way in a hurry would almost certainly be considerable, so that expenditure of coal and machinery lubricants would be greatly increased.

The point to be made here is that—independently of strategic conditions, which will be considered later—the difference in the supply of a given naval force in war and in peace is principally that in the former the requirements of nearly everything except provisions will be greater; and consequently that the articles must be forwarded in larger quantities or at shorter intervals than in peace time. If, therefore, we have arranged a satisfactory system of peace supply, that system—defence of the line of communications being left out of consideration for the present—will merely have to be expanded in time of war. In other words, practice in the use of the system during peace will go a long way towards preparing us for the duty of working it under war conditions. That a regular system will be absolutely indispensable during hostilities will not be doubted.

The general principles which I propose to indicate are applicable to any station. We may allow for a squadron composed of—

4 battleships,
4 large cruisers,
4 second-class cruisers,
13 smaller vessels of various kinds, and
3 destroyers,

being away from the principal base-port of the station for several months of the year. The number of officers and men would be, in round numbers, about 10,000.

In estimating the amounts of stores of different kinds required by men-of-war, it is necessary—in order to allow for proper means of conveyance—to convert tons of dead-weight into tons by measurement, as the two are not always exactly equivalent. In the following enumeration only estimated amounts are stated, and the figures are to be considered as approximate and not precise. It is likely that in each item an expert maybe able to discover some variation from the rigorously exact; but the general result will be sufficiently accurate for practical purposes, especially as experience will suggest corrections.

A thousand men require about 3.1 tons of victualling stores, packages included, daily, We may make this figure up to 3.5 tons to allow for 'medical comforts' and canteen stores, Consequently 10,000 men require about 35 tons a day, and about 6300 tons for six months. The assumed squadron, judging from experience, would require in peace time about 600 tons of engineers' stores, about 400 tons of naval stores, and—if the ships started with only their exact allowance on board and then carried out a full quarterly practice twice—the quantity of ordnance stores and ammunition required would be about 1140 tons, to meet the ordinary peace rate of expenditure, We thus get for a full six months' supply the following figures:—

Victualling stores 6,300 tons.
Engineers' stores 600 "
Naval stores 400 "
Ordnance stores and ammunition 1,140 "
——-
Total 8,440 "

Some allowance must be made for the needs of the 'auxiliaries,'[96] the vessels that bring supplies and in other ways attend on the fighting ships. This may be put at 7 per cent. The tonnage required would accordingly amount in all to about 9000.

[Footnote 96: The 7 per cent. mentioned in the text would probably cover nearly all the demands—except coal—of auxiliaries, which would not require much or any ammunition. Coal is provided for separately.]

The squadron would burn in harbour or when stationary about 110 tons of coal a day, and when under way about 1050 tons a day. For 140 harbour-days the consumption would be about 15,400 tons; and for 43 days under way about 45,150: so that for coal requirements we should have the following:—

Harbour consumption 15,400 tons.
Under-way consumption 45,150 "
———
Total for fighting ships 60,550 "
7 per cent. for auxiliaries (say) 4,250 "
———
Grand total 64,800 "

Some time ago (in 1902) a representation was made from the China station that, engine-room oil being expended whenever coal is expended, there must be some proportion between the quantities of each. It was, therefore, suggested that every collier should bring to the squadron which she was supplying a proportionate quantity of oil. This has been approved, and it has been ordered that the proportions will be 75 gallons of oil to every 100 tons of coal.[97] It was also suggested that the oil should be carried in casks of two sizes, for the convenience of both large and small ships.

[Footnote 97: I was informed (on the 10th December 1902), some time after the above was written, that the colliers supplying the United States Navy are going to carry 100 gallons of oil for every 100 tons of coal.]

There is another commodity, which ships have never been able to do without, and which they need now in higher proportion than ever. That commodity is fresh water. The squadron constituted as assumed would require an average of about 160 tons of fresh water a day, and nearly 30,000 tons in six months. Of this the ships, without adding very inconveniently to their coal consumption, might themselves distil about one-half; but the remaining 15,000 tons would have to be brought to them; and another thousand tons would probably be wanted by the auxiliaries, making the full six months' demand up to 16,000 tons.

The tonnage requirements of the squadron and its 'auxiliaries' for a full six months' period would be about 74,000, without fresh water. As, however, the ships would have started with full store-rooms, holds, and bunkers, and might be expected to return to the principal base-port of the station at the end of the period, stores for four-and-a-half months', and coal to meet twenty weeks', consumption would be sufficient. These would be about 6750 tons of stores and ammunition and 46,000 tons of coal.[98]

[Footnote 98: To avoid complicating the question, the water or distilling vessel, the hospital ship, and the repair vessel have not been considered specially. Their coal and stores have been allowed for.]

The stores, &c., would have to be replenished twice and—as it would not be prudent to let the ships run right out of them—replenishment should take place at the end of the second and at the end of the fourth months. Two vessels carrying stores and ammunition, if capable of transporting a cargo of nearly 1700 tons apiece, would bring all that was wanted at each replenishment. To diminish risk of losing all of one description of supplies, if carried by itself in a separate vessel, it has been considered desirable that each supply-carrier, when employed, is to contain some ammunition, some stores, and some provisions. There are great advantages in having supply-carriers, including, of course, colliers, of moderate size. Many officers must have had experience of the inconvenience and delay due to the employment of a single very large vessel which could only coal one man-of-war at a time. Several vessels, each carrying a moderate amount of cargo, would permit much more rapid replenishment of the ships of a squadron. The inconvenience that would be caused by the loss or breakdown of a supply-carrier would be reduced by employing several vessels of moderate cargo-capacity instead of only one or two of great capacity.

Each battleship and large cruiser of the assumed squadron may be expected to burn about 1000 tons of coal in five weeks, so that the quantity to be used in that time by all those ships would be 8000 tons. The remaining ships, scattered between different places as most of them would probably be, would require about 3500 tons. Therefore, every five weeks or so 11,500 tons of coal would be required. Four replenishments would be necessary in the whole period, making a total of 46,000 tons. Each replenishment could be conveyed in five colliers with 2300 tons apiece.

Moderate dimensions in store- and coal-carriers would prove convenient, not only because it would facilitate taking in stores and coaling, if all the squadron were assembled at one place, but also if part were at one place and part at another. Division into several vessels, instead of concentration in a few, would give great flexibility to the system of supply. A single very capacious cargo-carrier might have to go first to one place and supply the ships there, and then go to supply the remaining ships lying at another anchorage. This would cause loss of time. The same amount of cargo distributed amongst two or more vessels would permit the ships at two or more places to be supplied simultaneously.

You may have noticed that I have been dealing with the question as though stores and coal were to be transported direct to the men-of-war wherever they might be and put straight on board them from the carrying-vessels. There is, as you all know, another method, which may be described as that of 'secondary bases.' Speaking generally, each of our naval stations has a principal base at which considerable or even extensive repairs of the ships can be effected and at which stores are accumulated. Visits to it for the sake of repair being necessary, the occasion may be taken advantage of to replenish supplies, so that the maintenance of a stock at the place makes for convenience, provided that the stock is not too large. The so-called 'secondary base' is a place at which it is intended to keep in store coal and other articles in the hope that when war is in progress the supply of our ships may be facilitated. It is a supply, and not a repairing base.

A comparison of the 'direct' system and 'secondary base' system may be interesting. A navy being maintained for use in war, it follows, as a matter of course, that the value of any part of its equipment or organisation depends on its efficiency for war purposes. The question to be answered is—Which of the two systems promises to help us most during hostilities? This does not exclude a regard for convenience and economy in time of peace, provided that care is taken not to push economy too far and not to make ordinary peace-time convenience impede arrangements essential to the proper conduct of a naval campaign.

It is universally admitted that a secondary base at which stocks of stores are kept should be properly defended. This necessitates the provision of fortifications and a garrison. Nearly every article of naval stores of all classes has to be brought to our bases by sea, just as much as if it were brought direct to our ships. Consequently the communications of the base have to be defended. They would continue to need defending even if our ships ceased to draw supplies from it, because the communications of the garrison must be kept open. We know what happened twice over at Minorca when the latter was not done.

The object of accumulating stores at a secondary base is to facilitate the supply of fighting ships, it being rather confidently assumed that the ships can go to it to replenish without being obliged to absent themselves for long from the positions in which they could best counteract the efforts of the enemy. When war is going on it is not within the power of either side to arrange its movements exactly as it pleases. Movements must, at all events very often, conform to those of the enemy. It is not a bad rule when going to war to give your enemy credit for a certain amount of good sense. Our enemy's good sense is likely to lead him to do exactly what we wish him not to do, and not to do that which we wish him to do. We should, of course, like him to operate so that our ships will not be employed at an inconvenient distance from our base of supplies. If we have created permanent bases in time of peace the enemy will know their whereabouts as well as we do ourselves, and, unless he is a greater fool than it is safe to think he is, he will try to make us derive as little benefit from them as possible. He is likely to extend his operations to localities at a distance from the places to which, if we have the secondary base system of supply, he knows for certain that our ships must resort. We shall have to do one of two things—either let him carry on his operations undisturbed, or conform to his movements. To this is due the common, if not invariable, experience of naval warfare, that the fleet which assumes the offensive has to establish what are sometimes called 'flying bases,' to which it can resort at will. This explains why Nelson rarely used Gibraltar as a base; why we occupied Balaclava in 1854; and why the Americans used Guantanamo Bay in 1898. The flying base is not fortified or garrisoned in advance. It is merely a convenient anchorage, in a good position as regards the circumstances of the war; and it can be abandoned for another, and resumed, if desirable, as the conditions of the moment dictate.

It is often argued that maintenance of stocks of stores at a secondary base gives a fleet a free hand and at least relieves it from the obligation of defending the line of communications. We ought to examine both contentions. It is not easy to discover where the freedom comes in if you must always proceed to a certain place for supplies, whether convenient or not. It may be, and very likely will be, of the utmost importance in war for a ship to remain on a particular station. If her coal is running short and can only be replenished by going to a base, go to the base she must, however unfortunate the consequences. It has been mentioned already that nearly every item on our store list has to be brought to a base by sea. Let us ascertain to what extent the accumulation of a stock at a place removes the necessity of defending the communication line. Coal is so much the greater item that consideration of it will cover that of all the rest.

The squadron, as assumed, requires about 11,500 tons of coal every five weeks in peace time. Some is commonly obtained from contractors at foreign ports; but to avoid complicating the subject we may leave contract issues out of consideration. If you keep a stock of 10,000 tons at your permanent secondary base, you will have enough to last your ships about four-and-a-half weeks. Consequently you must have a stream of colliers running to the place so as to arrive at intervals of not more than about thirty days. Calculations founded on the experience of manoeuvres show that in war time ships would require nearly three times the quantity used in peace. It follows that, if you trebled your stock of coal at the base and made it 30,000 tons, you would in war still require colliers carrying that amount to arrive about every four weeks. Picture the line of communications with the necessary colliers on it, and see to what extent you are released from the necessity of defending it. The bulk of other stores being much less than that of coal, you could, no doubt, maintain a sufficient stock of them to last through the probable duration of the war; but, as you must keep your communications open to ensure the arrival of your coal, it would be as easy for the other stores to reach you as it would be for the coal itself. Why oblige yourself to use articles kept long in store when much fresher ones could be obtained? Therefore the maintenance of store depots at a secondary base no more releases you from the necessity of guarding your communications than it permits freedom of movement to your ships.

The secondary base in time of war is conditioned as follows. If the enemy's sphere of activity is distant from the base which you have equipped with store-houses and fortifications, the place cannot be of any use to you. It can, and probably will, be a cause of additional anxiety to you, because the communications of its garrison must still be kept open. If it is used, freedom of movement for the ships must be given up, because they cannot go so far from it as to be obliged to consume a considerable fraction of their coal in reaching it and returning to their station. The line along which your colliers proceed to it must be effectively guarded.

Contrast this with the system of direct supply to the ships-of-war. You choose for your flying base a position which will be as near to the enemy's sphere of action as you choose to make it. You can change its position in accordance with circumstances. If you cease to use the position first chosen you need trouble yourself no more about its special communications. You leave nothing at it which will make it worth the enemy's while to try a dash at it. The power of changing the flying base from one place to another gives almost perfect freedom of movement to the fighting ships. Moreover, the defence of the line communicating with the position selected is not more difficult than that of the line to a fixed base.

The defence of a line of communication ought to be arranged on the same plan as that adopted for the defence of a trade route, viz. making unceasing efforts to attack the intending assailant. Within the last few years a good deal has been written about the employment of cruisers. The favourite idea seems to be that peace-time preparation for the cruiser operations of war ought to take the form of scouting and attendance on fleets. The history of naval warfare does not corroborate this view. We need not forget Nelson's complaint of paucity of frigates: but had the number attached to his fleet been doubled, the general disposition of vessels of the class then in commission would have been virtually unaltered. At the beginning of 1805, the year of Trafalgar, we had—besides other classes—232 frigates and sloops in commission; at the beginning of 1806 we had 264. It is doubtful if forty of these were attached to fleets.

It is sometimes contended that supply-carriers ought to be vessels of great speed, apparently in order that they may always keep up with the fighting ships when at sea. This, perhaps, is due to a mistaken application of the conditions of a land force on the march to those of a fleet or squadron making a voyage. In practice a land army cannot separate itself—except for a very short time—from its supplies. Its movements depend on those of its supply-train. The corresponding 'supply-train' of a fleet or squadron is in the holds and bunkers of its ships. As long as these are fairly well furnished, the ships might be hampered, and could not be assisted, by the presence of the carriers. All that is necessary is that these carriers should be at the right place at the right time, which is merely another way of saying that proper provision should be made for 'the stream of supplies and reinforcements which in terms of modern war is called communications'—the phrase being Mahan's.

The efficiency of any arrangement used in war will depend largely on the experience of its working gained in time of peace. Why do we not work the direct system of supply whilst we are at peace so as to familiarise ourselves with the operations it entails before the stress of serious emergency is upon us? There are two reasons. One is, because we have used the permanent base method so long that, as usually happens in such cases, we find it difficult to form a conception of any other. The other reason is that the direct supply method is thought to be too costly. The first reason need not detain us. It is not worthy of even a few minutes' consideration. The second reason deserves full investigation.

We ought to be always alive to the necessity of economy. The only limit to economy of money in any plan of naval organisation is that we should not carry it so far that it will be likely to impair efficiency. Those who are familiar with the correspondence of the great sea-officers of former days will have noticed how careful they were to prevent anything like extravagant expenditure. This inclination towards a proper parsimony of naval funds became traditional in our service. The tradition has, perhaps, been rather weakened in these days of abundant wealth; but we should do our best not to let it die out. Extravagance is a serious foe to efficient organisation, because where it prevails there is a temptation to try imperfectly thought-out experiments, in the belief that, if they fail, there will still be plenty of money to permit others to be tried. This, of course, encourages slovenly want of system, which is destructive of good organisation.

We may assume, for the purposes of our investigation, that our permanently equipped secondary base contains a stock of 10,000 tons of coal. Any proportionate quantity, however, may be substituted for this, as the general argument will remain unaffected. As already intimated, coal is so much greater in bulk and aggregate cost than any other class of stores that, if we arrange for its supply, the provision of the rest is a comparatively small matter. The squadron which we have had in view requires an estimated amount of 46,000 tons of coal in six months' period specified, and a further quantity of 4600 tons may be expected to suffice for the ships employed in the neighbouring waters during the remainder of the year. This latter amount would have to be brought in smaller cargoes, say, five of 920 tons each. Allowing for the colliers required during the six months whilst the whole squadron has to be supplied an average cargo of 2300 tons, we should want twenty arrivals with an aggregate of 46,000 tons, and later on five arrivals of smaller colliers with an aggregate of 4600 tons to complete the year.

The freight or cost of conveyance to the place need not be considered here, as it would be the same in either system. If we keep a stock of supplies at a place we must incur expenditure to provide for the storage of the articles. There would be what may be called the capital charges for sites, buildings, residences, jetties, tram lines, &c., for which £20,000 would probably not be enough, but we may put it at that so as to avoid the appearance of exaggeration. A further charge would be due to the provision of tugs or steam launches, and perhaps lighters. This would hardly be less than £15,000. Interest on money sunk, cost of repairs, and maintenance, would not be excessive if they amounted to £3500 a year. There must be some allowance for the coal used by the tugs and steam launches. It is doubtful if £500 a year would cover this; but we may put it at that. Salaries and wages of staff, including persons employed in tugs and steam launches, would reach quite £2500 a year. It is to be noted that the items which these charges are assumed to cover cannot be dispensed with. If depots are established at all, they must be so arranged that the stores deposited in them can be securely kept and can be utilised with proper expedition. The total of the charges just enumerated is £6500 a year.

There are other charges that cannot be escaped. For example, landing a ton of coal at Wei-hai-wei, putting it into the depot, and taking it off again to the man-of-war requiring it, costs $1 20 cents, or at average official rate of exchange two shillings. At Hong-Kong the cost is about 2s. 5d. a ton. The charge at 2s. per ton on 50,600 tons would be £5060. I am assured by every engineer officer to whom I have spoken on the subject that the deterioration in coal due to the four different handlings which it has to undergo if landed in lighters and taken off again to ships from the coal-store cannot be put at less than 10 per cent. Note that this is over and above such deterioration as would be due to passing coal direct from the hold of a collier alongside into a ship's bunkers. If anyone doubts this deterioration it would be well for him to examine reports on coal and steam trials. He will be unusually fortunate if he finds so small a deterioration as 10 per cent. The lowest that I can remember having seen reported is 20 per cent.; reports of 30 and even 40 per cent. are quite common. Some of it is for deterioration due to climate and length of time in store. This, of course, is one of the inevitable conditions of the secondary base system, the object of which is to keep in stock a quantity of the article needed. Putting the purchase price of the coal as low as 15s. a ton, a deterioration due to repeated handling only of 10 per cent. on 50,600 tons would amount to £3795.

There is nearly always some loss of coal due to moving it. I say 'nearly always' because it seems that there are occasions on which coal being moved increases in bulk. It occurs when competitive coaling is being carried on in a fleet and ships try to beat records. A collier in these circumstances gives out more coal than she took in. We shall probably be right if we regard the increase in this case as what the German philosophers call 'subjective,' that is, rather existent in the mind than in the external region of objective, palpable fact. It may be taken as hardly disputable that there will be less loss the shorter the distance and the fewer the times the coal is moved. Without counting it we see that the annual expenses enumerated are—

Establishment charges £6,500
Landing and re-shipping 5,060
Deterioration 3,795
———-
£15,355

This £15,355 is to be compared with the cost of the direct supply system. The quantity of coal required would, as said above, have to be carried in twenty colliers—counting each trip as that of a separate vessel—with, on the average, 2300 tons apiece, and five smaller ones. It would take fully four days to unload 2300 tons at the secondary base, and even more if the labour supply was uncertain or the labourers not well practised. Demurrage for a vessel carrying the cargo mentioned, judging from actual experience, would be about £32 a day; and probably about £16 a day for the smaller vessels. If we admit an average delay, per collier, of eighteen days, that is, fourteen days more than the time necessary for removing the cargo into store, so as to allow for colliers arriving when the ships to be coaled are absent, we should get—

20 X 14 X 32 £8,960
5 X 14 X 16 1,120
———-
£10,080

as the cost of transferring the coal from the holds to the men-of-war's bunkers on the direct supply system. An average of eighteen days is probably much too long to allow for each collier's stay till cleared: because, on some occasions, ships requiring coal may be counted on as sure to be present. Even as it is, the £10,080 is a smaller sum than the £11,560 which the secondary base system costs over and above the amount due to increased deterioration of coal. If a comparison were instituted as regards other kinds of stores, the particular figures might be different, but the general result would be the same.

The first thing that we have got to do is to rid our minds of the belief that because we see a supply-carrier lying at anchor for some days without being cleared, more money is being spent than is spent on the maintenance of a shore depot. There may be circumstances in which a secondary base is a necessity, but they must be rare and exceptional. We saw that the establishment of one does not help us in the matter of defending our communications. We now see that, so far from being more economical than the alternative method, the secondary base method is more costly. It might have been demonstrated that it is really much more costly than the figures given make it out to be, because ships obliged to go to a base must expend coal in doing so, and coal costs money. It is not surprising that consideration of the secondary base system should evoke a recollection of the expression applied by Dryden to the militia of his day:

In peace a charge; in war a weak defence.

I have to say that I did not prepare this paper simply for the pleasure of reading it, or in order to bring before you mere sets of figures and estimates of expense. My object has been to arouse in some of the officers who hear me a determination to devote a portion of their leisure to the consideration of those great problems which must be solved by us if we are to wage war successfully. Many proofs reach me of the ability and zeal with which details of material are investigated by officers in these days. The details referred to are not unimportant in themselves; but the importance of several of them if put together would be incomparably less than that of the great question to which I have tried to direct your attention.

The supply of a fleet is of high importance in both peace time and time of war. Even in peace it sometimes causes an admiral to pass a sleepless night. The arrangements which it necessitates are often intricate, and success in completing them occasionally seems far off. The work involved in devising suitable plans is too much like drudgery to be welcome to those who undertake it. All the same it has to be done: and surely no one will care to deny that the fleet which has practised in quiet years the system that must be followed in war will start with a great advantage on its side when it is at last confronted with the stern realities of naval warfare.

POSTSCRIPT

The question of 'Communications,' if fully dealt with in the foregoing paper, would have made it so long that its hearers might have been tired out before its end was reached. The following summary of the points that might have been enlarged upon, had time allowed, may interest many officers:—

In time of war we must keep open our lines of communication.

If we cannot, the war will have gone against us.

Open communications mean that we can prevent the enemy from carrying out decisive and sustained operations against them and along their line.

To keep communications open it is not necessary to secure every friendly ship traversing the line against attacks by the enemy. All that is necessary is to restrict the enemy's activity so far that he can inflict only such a moderate percentage of loss on the friendly vessels that, as a whole, they will not cease to run.

Keeping communications open will not secure a friendly place against every form of attack. It will, however, secure a place against attacks with large forces sustained for a considerable length of time. If he can make attacks of this latter kind, it is clear that the enemy controls the communications and that we have failed to keep them open.

If communications are open for the passage of vessels of the friendly mercantile marine, it follows that the relatively much smaller number of supply-vessels can traverse the line.

As regards supply-vessels, a percentage of loss caused by the enemy must be allowed for. If we put this at 10 per cent.—which, taken absolutely, is probably sufficient—it means that _on_the_ average out of ten supply-vessels sent we expect nine to reach their destination.

We cannot, however, arrange that an equal loss will fall on every group of ten vessels. Two such groups may arrive intact, whilst a third may lose three vessels. Yet the 10 per cent. average would be maintained.

This condition has to be allowed for. Investigations some years ago led to the conclusion that it would be prudent to send five carriers for every four wanted.

The word 'group' has been used above only in a descriptive sense. Supply-carriers will often be safer if they proceed to their destination separately. This, however, depends on circumstances.