strandings on record, it is surprising that the loss in lives and property has been so small. Various reasons may be advanced in explanation of this fact, one of them undoubtedly being the failure of the navigator to realize that currents of considerable velocity are frequently encountered when there are no other unfavorable local conditions to warn him of their existence.

4. The commonly accepted rule among navigators regarding the currents has been that they follow the prevailing winds, setting, in general, southward in summer and northward in winter. Recent observations indicate that the current is apt to be from 20° left to 20° right of the direction of the wind. See page 25.

5. In the majority of the cases where the strandings appear to have been directly due to currents, the currents have been against the vessel. Most of the strandings have happened to deeply laden, southbound vessels to the northward of the projecting points like Capes Blanco, Mendocino, and Arena. The consensus of opinion among the navigators of the coast is that the currents follow the curves of the shore. If this is true, a vessel southbound against a northerly current would experience a tendency to set in to the northward of the points and out to the southward of them. As a specific instance, one navigator states: "If you have seen Blanco and Northwest Seal Rocks and find you have been set off a little and the speed made good retarded some, then you can be sure you will be set in toward Mendocino, or if you have set in toward Seal Rocks and your speed has been accelerated, then you can be sure you will be set off on nearing Mendocino." The general configuration of the coast tends to support this theory. As already stated, wrecks to southbound vessels occur to the northward of Capes Blanco, Mendocino, and Arena. More northbound vessels have been lost in the vicinity of Punta Gorda than at any other point along the coast. It is in these localities that the deviation of the coast from its general north and south direction is greatest.

There is one serious objection to this theory that the currents follow the curves of the shore. It can readily be seen how a current flowing in a general north and south direction would be deflected to the westward by the points projecting in that direction, resulting in a tendency to set the vessel offshore; a set experienced as she approached the point if traveling with the current, or after passing it if the current was against her. But it is difficult to conceive of any agency which could redeflect that current to the eastward after it had passed a point which had already caused it to swing off to the west, although such conditions would undoubtedly cause a local eddy current of considerable extent.

There are, however, some reasons for believing that the phenomena which have been observed are caused by currents which originate well offshore and flowing in strike the coast and are deflected to the north or south. This theory would explain the fact, already noted, that currents are so frequently encountered in relatively calm weather. It would also explain the fact that vessels have frequently experienced a considerable set directly inshore caused by currents acting so squarely across the track that they had no effect on the speed made good. Sets of this character appear to be particularly frequent between Heceta Bank and Cape Arago, between Trinidad and Cape Mendocino, and off Monterey Bay.

Under the conditions above described, it is obvious that there is only one method of safe navigation on this coast in thick weather. That is by means of the lead. It is the method which has been relied upon by the men who have navigated the coast in safety for years; its neglect has contributed directly to the great majority of the strandings which have occurred.

The master must assume the possible existence of a current which is setting his ship into danger, and take his precautions accordingly. The vessel's progress should be checked by an occasional sounding on each course where the depths permit, and in approaching each important danger or turning point soundings should be taken frequently for some time both before and after the change of course, unless in the meantime a reliable fix has been obtained. The soundings after the change are of the greatest value as revealing any error in the reckoning on which the change of course is based, and it may conservatively be stated that had such soundings been taken the great majority of the past disasters would have been prevented.

Navigation by means of soundings renders imperative a careful study of the chart. The navigator must learn what, for any given locality, are the critical characteristic features revealed by his lead which insure his safety or indicate the proximity to danger. What depths to follow and what to avoid; localities where soundings may be taken to advantage to obtain a check on the position; information revealed by the character of the bottom; and perhaps most important of all, as being the condition most likely to cause trouble even for the careful navigator, certain areas which duplicate the critical depths of the track, so that if the former were mistaken for the latter the result might be most serious; all these are items of the utmost importance.

Since the safety of all concerned must frequently depend on the soundings alone, it is essential that to the operation should be devoted a degree of skill and care commensurate with its importance. It is usually impossible for the master to give his personal attention to the task, but he should see that the man to whom he intrusts it is so carefully trained and so impressed with the importance of his duty that a mistake is next to impossible.

There is a method in common use on the coast of sounding without using pressure tubes, the depth being estimated from the amount of wire out. Such a method is perhaps justified for every other cast while feeling for the bottom as the vessel approaches soundings from deep water, but once the bottom has been picked up it should never be trusted. There are too many factors to be considered, and all of them uncertain and variable; the speed of the ship, the smoothness with which the reel is working, and, above all, the "personal equation" of the operator. He will be too much influenced by the depths which he thinks he should find. If he expects bottom in 30 fathoms (55 m.) he will pay out the wire so slowly that he probably will not find the bottom in a depth of 60 or 70 fathoms (110 or 128 m.). If he expects 80 to 100 fathoms (146 to 183 m.) he may get bottom in 25 or 30 (46 or 55 m.) and never know it. The records clearly show that this method of sounding has resulted in the loss of vessels 83405°-26-3

through mistakes which could not have gone undetected if a tube had been used.

So, for every sounding, a pressure tube should be used and the lead should be armed to bring up a sample of the bottom. The amount of wire out should, of course, be reported, for that does give a general idea of the depth some moments before the tube can be reeled in. But this estimated depth should be verified by the tube and the sample of bottom obtained should be compared with that shown on the chart.

Finally, it is important to realize that under certain conditions pressure tubes are subject to considerable errors, with which the navigator should be familiar if he is to get full value for them. A statement regarding the errors usually found in sounding tubes will be found in the appendix to this volume.

The introduction of radiocompass stations ashore, and of radiocompasses on board ship, have given the navigator additional ways of determining his position with a fair degree of accuracy, but the lead should never be abandoned.

Due to the fact that there are certain conditions under which radio bearings may be subjected to grave error, the additional check of sounding in critical places should be carried out. One of the worst marine disasters of recent years on the Pacific coast was due to an erroneous radio bearing being received from a shore station. the last analysis, the lead is the navigator's best safeguard. Table of distances in nautical miles

[Based on courses recommended in this volume]

In

1 One course from Umatilla Lightship to Cape Blanco.

NOTE. All distances to San Francisco are via the San Francisco Lightship.

DESCRIPTIONS AND SAILING DIRECTIONS

DIRECTIONS, SAN DIEGO TO THE STRAITS OF FUCA

Vessels may use the following directions, which give approximately the track followed by the high-powered steamers plying regularly between San Diego, Los Angeles, San Francisco, Columbia River, and Puget Sound ports. These courses are used by such vessels in preference to others farther off-shore by reason of the fact that they lead well within range of the various fog signals and in so far as possible over depths where the lead may be used to obtain a check on the position.

Low-powered local steamers usually keep close inshore, following, in general, the curves of the land, in order to escape the full effect of wind and sea. In clear weather strangers may readily follow this inshore track by means of the chart; in thick weather they are advised not to use it, as the fog signals are few and far apart, and the currents variable and uncertain, making detailed local knowledge essential to safety. For that reason no directions for this track are given.

A detailed description of the coast, including landmarks, dangers, etc., follows these directions, beginning on page 34.

The following brief summary of the methods actually employed in thick weather, by the ablest masters on the coast, indicates the methods and precautions by which safety is assured.

Northbound.-From San Diego to Los Angeles the conditions are seldom such as to cause any deviation from the track. If uncertain of the position in approaching San Pedro Bay, steer so as to make sure of being to the eastward of the breakwater. Continue to a depth of 9 to 10 fathoms (16.4 to 18.3 m.), and then haul to the westward in that depth, and the fog signal will be made without difficulty.

Bound for San Francisco, the departure is taken from Los Angeles Lighthouse, and the buoy at Point Fermin and Point Vincente Light are made close to. Crossing Santa Monica Bay, the possibility of a northerly current setting into the bay should be borne in mind, and shortly after passing Point Dume the lead should be started, as the depths, over alternating banks and submarine valleys, are characteristic.

Having made Point Hueneme in this way, the lead may be given a rest until approaching Point Conception. Here it should be used to guard against an inshore set, and the depths should not be shoaled to less than 50 fathoms (91 m.). From Point Conception, Point Arguello will readily be made.

The track from Point Arguello to Point Sur is a long one, on which currents of considerable velocity are frequently encountered, and to the southward of Point Sur depths of over 100 fathoms (183 m.) extend so close to the beach that a vessel can not count on getting bottom with the lead in time to prevent disaster. Point Sur, therefore, should be given a wide berth. If, on this track, the weather has not cleared by the time Piedras Blancas has been reached, the vessel should be hauled out 2° or 3°, and great caution should be exercised as Point Sur is approached.

The lead should find bottom off Point Sur, but even if it does not, no difficulty should be experienced in making a landfall northward of Monterey Bay, as the depths shoal very gradually from the 100fathom (183 m.) curve to the beach. The track to the lightship may then be followed by means of the lead.

Detailed local knowledge is necessary for entering the Golden Gate in thick weather, because of the strong irregular currents and tide rips. At times, however, it will be clear within the Heads when it is foggy outside. It is well, therefore, to stand in cautiously as far as the whistling buoy; if from that point Point Bonita can not be seen, the vessel should be anchored until the weather clears.

Southbound. The courses from the bar to Point Sur are short and should be easy to make good, especially as the 100-fathom (183 m.) curve extends well offshore to the northward of Point Sur, affording ample opportunity for checking the vessel's position by the lead as the point is approached.

Likewise, on the long course from Point Sur to Point Arguellonorthward of Point Arguello the soundings extend well offshore and the point may be reached without difficulty. If the lead shows 30 fathoms (55 m.), haul to a south-southeast (mag.) course, keeping in that depth, and if the water deepens to over 40 fathoms (73 m.) the vessel will be past the point, and may be hauled up for Point Conception.

Again, in approaching Point Hueneme, the lead may be used to guide the vessel to within sound of the fog signal, as the depths are