On the other hand, by almost abandoning the present modes, and adopting measures which I shall point out presently, adapted to the new circumstances, a much greater degree of certainty and accuracy may be attained than is now even sought for. I have had the best advice on these points, both astronomical and nautical: the Astronomer Royal, Mr. Airy, who both as a man of science and a practical man, and by his official position, is the first authority on such matters, and Professor Smyth, of the Edinburgh Observatory, Captain Beecher of the Admiralty, and several other scientific naval men, have assisted me; and, under their advice, instruments are being constructed, and a system devised, which will admit of continuous observations being made with great accuracy at all times of the day, and particularly at night, and by means of which also a continuous correction of the ship’s compasses with the most minute accuracy can be kept up, and her position be ascertained with almost the same accuracy as a point on land; and I have their authority for saying that such improved means are desirable, and are attainable.
The importance and advantage of continuous observation throughout the twenty-four hours, whenever a glimpse can be obtained of any object which will answer the purpose, and even when the horizon is invisible, may not at first be evident, but it cannot be over-estimated. An exact knowledge of the ship’s movements will be soon acquired that would almost replace observation, and the average of numerous observations secures an accuracy which cannot be approached by any other method.
By a careful and continuous comparison of the exact distances run, with accurate records of the speed of the engine and of the ship through the water, registered by good instruments (the performance of which has been tested, and which are being made), and having proper reference to the varying draught of water of the vessel, the most precise measure of the speed of the vessel through the water can be learnt; and by careful observation of the force and direction of the wind, the effect of any given wind, and an accurate measure of her drift or lee-way, may be obtained; and then, by adhering strictly, without regard to wind or weather, to a course previously laid down on good charts, having upon them the sets of currents, as already observed, the true position of the ship may be determined at any moment, and there need never be the slightest hesitation, or any time or distance lost by doubts.
In addition to the instruments above named, I hope to be able to provide the means of sounding at moderate depths while the ship is going her full speed.
Having the means, then, of determining the ship’s course and position with much greater accuracy than is now practised, we must seek to make that course, or the distance to be run, the shortest possible, that is to say, the course which will occupy the least time.
The exact course to be taken by such a vessel must be determined upon and laid down upon the charts after a due consideration of all the circumstances which can possibly affect the time occupied in the voyage between any two points, and particularly by examining and considering well all the information which scientific observers have collected and recorded as to the currents, probabilities of fogs, or of ice, and other impediments, the chances of meeting vessels, which must be avoided as much as possible, the average direction of prevailing winds, varying such course, perhaps, in certain latitudes with the season of the year, but certainly not with the temporary direction or force of the winds or state of weather at the moment; for the speed which we shall attain renders these causes of secondary consideration, and would interfere with all ordinary calculations derived from present experience of the probable state of the wind in the new position which the ship would attain after a few hours’ run. The business of the commander would be, therefore, to adhere rigidly to the exact course previously deliberately determined upon, and not to be tempted to deviate except slightly, and even then only according to rules which he shall have previously laid down for himself.
The importance of adhering strictly to this rule cannot be over-estimated. The period occupied in a voyage will be materially influenced by the exact course followed, and as such course must be determined upon only by a calm and somewhat laborious study of documents, it cannot be safely determined upon except in the closet, that is, before the voyage, and uninfluenced by the excitement of hopes or by disappointments caused by difficulties.
The safety of the ship and of the enterprise may also mainly depend upon the rigid adherence to this rule.
With the means at his disposal for checking that course, and with the method and regularity involved by a rigid adherence to it, and a correction at once of any departure from it, a degree of certainty will be attained as to the ship’s position which will almost preclude the possibility of an accident, and which I consider practically invaluable as affecting the safety of our vessel. This rigid adherence to an exactly prescribed course will prevent any risk of that which is the cause of the greater number of losses. No inducement of fine weather, or a happy state of mind and body of the captain, or a desire to save time, or to show the beauties of a coast, or any other temporary cause, will lead to a nearer approach to dangerous points than had been previously determined upon as safe. The shortest and best route, the safest from all dangers, and giving the widest berth to all shores or shoals, having been laid down, must be kept to against all temptations.
Economy of fuel is another consideration of the highest importance. The engines are of power sufficient, if fully worked, to consume considerably more than the cargo provided. Large as may be the supply which the ship is capable of carrying, it is no more than that which is calculated as necessary for the voyage intended, with a moderate allowance for contingencies; and it must be borne in mind that the ordinary means of making up any deficiencies would be totally inapplicable in our case, since no supply capable of being drawn in an emergency from other sources would be sufficient.