These errors are due chiefly to uneven bore of tube, variation of barometric pressure from normal, difference in temperature of air and water, uneven thickness of caps used to close one end of the tube, leakage of water, accumulated salt in the tube, and leakage or failure of gaskets and valves used in the construction of some types of tube.

In order to avoid serious errors tubes should, therefore, be used with the greatest care. A type that can be used more than once should be adopted and the tubes to be used for sounding to make a landfall should be tested beforehand by stopping for an up and down cast, sending them down on the sounding wire to any desired depth, and comparing their readings with the actual depth to which they were submerged. Additional tests of this nature from time to time during the sounding operations are also valuable. Special care should be taken to prevent leakage by making sure that the cap fits tightly or that the valve and gaskets are water-tight and are working properly. In using the valve type of tube, it is very important to make sure that the tube does not submerge after it once clears the water.

CURRENTS AT LIGHTSHIPS

For several years current observations have been made at San Francisco, Blunts Reef, Columbia River, Umatilla Reef, and Swiftsure Bank Lightships. A discussion in detail of the observations at each of the lightships will be found in Coast and Geodetic Survey Special Publication No. 121, entitled "Coastal Currents Along the Pacific Coast of the United States." In general it may be said these observations show that winds here bring about a current having a velocity 2 per cent that of the wind, the direction of this wind-driven current being about 20° to the right of the wind with winds from the northeast, southeast, and northwest quadrants, and about 20° to the left of the wind with winds from the southwest quadrant. A summary of the results of these observations at each of the light vessels is given below.

SAN FRANCISCO LIGHTSHIP

Tidal Current.--The tidal current here is rotary, turning clockwise, and is largely diurnal, that is, revolving in a period of about 25 hours. At strength the current has a velocity averaging less than 2 knot, setting southeastward about an hour before higher low water at San Francisco, and northwestward about 2 hours after lower low water.

Nontidal Current.-During the winter months there is a nontidal current with an average velocity of about 4 knot, setting northwesterly. During the summer months this nontidal current is weaker, averaging about knot, the direction being variable and frequently southerly. The direction and velocity of the average nontidal current is very considerably modified by the current due to the wind.

Wind Current.-In general the wind current here is about 2 per cent that of the wind, but currents coming with winds from the southeast quadrant are stronger than the average, while the currents coming with winds from the northwest quadrant are weaker than the average.

BLUNTS REEF LIGHTSHIP

Tidal Current.-The tidal current at this light vessel is weak, having at strength a velocity of less than 1/4 knot. It is therefore completely masked by nontidal currents due chiefly to the wind.

Nontidal Current.-The nontidal current here has a velocity averaging about 14 knot, setting southwesterly. During the winter months the wind is prevailingly from the southeast and during these months the nontidal current sets northwesterly.

Wind Current. The observations bring out the fact that here the current, due to a wind of given strength, is practically the same for all directions of the wind, the velocity of the current being about 2 per cent that of the wind. The direction of the wind-driven current obeys the general rule for this coast that winds from the northeast, southeast, and northwest quadrants bring about currents the directions of which are about 20° to the right of the wind, while winds from the southwest quadrant bring about currents setting about 20° to the left of the wind.

COLUMBIA RIVER LIGHTSHIP

Tidal Current. The tidal current at Columbia River Lightship is of the rotary type with a velocity at strength of flood or ebb of a 14 knot. This tidal current, however, is completely masked by nontidal currents due to river discharge and winds.

Nontidal Current.-At Columbia River Lightship there is a nontidal current averaging knot with a set to the west-southwestward. This nontidal current is due largely to the discharge from the Columbia River and therefore varies with the seasons. It is greatest during the summer months, averaging then more than 11⁄2 knot. The direction of the average nontidal current is also subject to a seasonal variation, setting southwesterly in the spring and summer months and northwesterly in the fall and winter months. This variation in direction is due to the winds.

Wind Current.-Along this part of the coast the wind is prevailingly from the northwest in the spring and summer months and from the east and southeast during the fall and winter months. Because of the nontidal current due to river discharge, the direction of which is west-southwest, northerly winds are accompanied by stronger currents than southerly winds. Away from the influence of the river current the general rule holds good that the velocity of the current is about 2 per cent that of the wind and that winds from the northeast, southeast, and northwest quadrants bring about currents that set about 20° to the right of the wind, while the currents accompanying winds from the southwest quadrant set about 20° to the left of the wind.

UMATILLA REEF LIGHTSHIP

Tidal Current.-The tidal current here is only slightly rotary, setting N. 15° W. on the flood and S. 15° E. on the ebb with a velocity at strength of about knot.

Nontidal Current.-The nontidal current at Umatilla Reef Lightship shows a very distinct seasonal variation. During the winter months this current sets northerly with a velocity which averages % knot, while in summer it sets southerly with a velocity of about 1% knot.

Wind Current.-Here the prevailing wind is from the east and southeast in winter and from the west and northwest in summer. The southerly winds bring about stronger currents than the northerly winds, the current with the southerly winds being about 3 per cent of the wind, while with the northerly winds the current is about 12 per cent that of the wind. The general rule for the deviation of the wind-driven current from the direction of the wind, namely, currents brought about by winds from the northeast, southeast, and northwest quadrants set about 20° to the right of the wind, while with winds from the southwest quadrant the current sets about 20° to the left of the wind, is applicable here.

SWIFTSURE BANK LIGHTSHIP

Tidal Current.-At this light vessel the tidal current is distinctly rotary, turning clockwise. At strength of flood or ebb the current has a velocity of 34 knot on the average. Strength of flood sets southeasterly and comes about 12 hours after high water at Astoria; strength of ebb sets northwesterly and comes about 1 hour after low water at Astoria.

Nontidal Current.-At Swiftsure Bank Lightship the nontidal current has a velocity averaging 2 knot, setting northwest. This is due largely to the drainage waters flowing seaward through the Strait of Juan de Fuca. The velocity of the nontidal current is greatest during the fall and winter months when it averages somewhat more than 2 knot, this increase being due to the effect of the wind.

Wind Current.—The prevailing wind here is from the east during the fall and winter months and from the west and southwest during spring and summer. Due to the northwesterly setting nontidal current arising from the discharge of the drainage waters through the Strait of Juan de Fuca, the strongest currents at Swiftsure Bank Lightship come with southeasterly winds and the weakest with northwesterly winds. In general it may be said that winds from the southeast quadrant here bring about currents having a velocity about 3 per cent that of the wind while winds from the northwest quadrant bring about currents with a velocity about 1 per cent that of the

wind.

The general rule for the deviation of the wind-driven current from the direction of the wind does not hold good here, not only because of the effect of the northwesterly setting nontidal current, but also because of the fact that the coast line here is to the north of the light vessel, while for the other light vessels it is to the east. For an approximate general rule here it may be taken that with winds from the southeast, southwest, and northwest quadrants the current sets about 20° to the right of the wind, while with winds from the northeast quadrant the current sets about 20° to the left of the wind.

INSTRUCTIONS TO MARINERS IN CASE OF SHIPWRECK AS PUBLISHED BY THE UNITED STATES COAST GUARD SERVICE

GENERAL INFORMATION

Life-saving stations and houses of refuge are located upon the Atlantic and Pacific seaboard of the United States, the Gulf of Mexico, and the lake coasts. All stations on the Atlantic coast are manned annually by crews of experienced surfmen; upon the lake coasts the stations are manned from the opening until the close of navigation, with the exception of the one on Beaver Island, Lake Michigan, which depends on a volunteer crew; and upon the Pacific coast they are open and manned throughout the year.

All life-saving stations are fully supplied with boats, wreck guns, beach apparatus, restoratives, clothing provided by the Women's National Relief Association for the shipwrecked requiring it, etc.

Houses of refuge are supplied with boats, provisions, and restoratives, but not manned by crews; a keeper, however, resides in each, who is required to make extended excursions along the coast after every storm, with a view of ascertaining if any shipwreck has occurred and finding and succoring any persons that may have been cast ashore.

Houses of refuge are located exclusively upon the Florida coast, where the requirements of relief are widely different from those of any other portion of the seaboard.

The life-saving stations are provided with the International Code of Signals, and vessels can, by opening communication, be reported; or obtain the latitude and longitude of the station, where determined; or information as to the weather probabilities in most cases; or, where facilities for the transmission of messages by telephone or telegraph are available, requests for a tug or Coast Guard cutter will be received and promptly forwarded.

All services are performed by the life-saving crews without other compensation than their wages from the Government.

Destitute seafarers are provided with food and lodging at the nearest station by the Government as long as necessarily detained by the circumstances of shipwreck, and, if needed, with clothing provided by the Women's National Relief Association.

The station crews patrol the beach from 2 to 4 miles each side of their stations between sunset and sunrise, and if the weather is foggy the patrol is continued through the day. A continuous lookout is also maintained at every station night and day.

Each patrolman carries Coston signals. Upon discovering a vessel standing into danger he ignites one of these, which emits a brilliant red flame of about two minutes' duration, to warn her off, or, should the vessel be ashore, to let her crew know that they are discovered and assistance is at hand.

If the vessel is not discovered by the patrol immediately after striking, rockets, flare-up lights, or other recognized signals of distress should be used. If the weather be foggy, some recognized sound signal should be made to attract attention, as the patrolman may be some distance away at the other end of his beat.

Masters are particularly cautioned, if they should be driven ashore anywhere in the neighborhood of the stations, to remain on board until assistance arrives, and under no circumstances should they attempt to land through the surf in their own boats until the last hope of assistance from the shore has vanished. Often when comparatively smooth at sea a dangerous surf is running which is not perceptible 400 yards offshore, and the surf when viewed from a vessel never appears as dangerous as it is. Many lives have been lost unnecessarily by the crews of stranded vessels being thus deceived and attempting to land in the ship's boats.

The difficulties of rescue by operations from the shore are greatly increased in cases where the anchors are let go after entering the breakers, as is frequently done, and the chances of saving life correspondingly lessened.

RESCUE WITH THE LIFEBOAT OR SURFBOAT

The patrolman, after discovering your vessel ashore and burning a Coston signal, hastens to his station or the telephone for assistance. If the use of a boat is practicable, either the large lifeboat is launched from its ways in the station and proceeds to the wreck by water or the lighter surfboat is hauled overland to a point opposite the wreck and launched, as circumstances may require.

Upon the boat reaching your vessel, the directions and orders of the keeper (who always commands and steers the boat) should be implicitly obeyed. Any headlong rushing and crowding should be prevented, and the captain of the vessel should remain on board, to preserve order, until every other person has left.

Women, children, helpless persons, and passengers should be passed into the boat first.

Goods or baggage will positively not be taken into the boat until all are landed. If any be passed in against the keeper's remonstrance, he is fully authorized to throw the same overboard.

RESCUE WITH THE BREECHES BUOY OR LIFE CAR

Should it be inexpedient to use either the lifeboat or surfboat, recourse will be had to the wreck gun and beach apparatus for the rescue by the breeches buoy or the life car.

A shot with a small line attached will be fired across your vessel. Get hold of the line as soon as possible and haul on board until you get a tailblock with a whip or endless line rove through it. This tailblock should be hauled on board as quickly as possible to prevent the whip drifting off with the set or fouling with wreckage, etc. Therefore, if you have been driven into the rigging, where but one or two men can work to advantage, cut the shot line and run it through some available block, such as the throat or peak halyards block, or any block which will afford a clear lead, or even between the ratlines, that as many as possible may assist in hauling.

Attached to the tailblock will be a tally board with the following directions in English on one side and French on the other:

"Make the tail of the block fast to the lower mast, well up. If the masts are gone, then to the best place you can find. Cast off shot line, see that the rope in the block runs free, and show signal to the shore."

The above instructions being complied with, the result will be as shown in Figure 1.

As soon as your signal is seen a 3-inch hawser will be bent onto the whip and hauled off to your ship by the life-saving crew.

If circumstances permit, you can assist the life-saving crew by manning that part of the whip to which the hawser is bent and hauling with them. When the end of the hawser is got on board, a tally board will be found attached, bearing the following directions in English on one side and French on the other:

"Make this hawser fast about 2 feet above the tail block, see all clear and that the rope in the block runs free, and show signal to the shore.”

These instructions being obeyed, the result will be as shown in Figure 2.

Figure 2.

Take particular care that there are no turns of the whip line round the hawser. To prevent this, take the end of the hawser UP BETWEEN the parts of the whip before making it fast.

When the hawser is made fast, the whip cast off from the hawser, and your signal seen by the life-saving crew, they will haul the hawser taut and by means of the whip will haul off to your vessel a breeches buoy suspended from a traveler block, or a life car, from rings running on the hawser.

Figure 3, below, represents the apparatus rigged, with the breeches buoy hauled off to the ship.

If the breeches buoy be sent, let one man immediately get into it, thrusting his legs through the breeches. If the life car, remove the hatch, place as

Figure 3.

many persons therein as it will hold (four to six) and secure the hatch on the outside by the hatch bar and hook, signal as before, and the buoy or car will be hauled ashore. This will be repeated until all are landed. On the last trip of the life car the hatch must be secured by the inside hatch bar.

In many instances two men can be landed in the breeches buoy at the same time by each putting a leg through a leg of the breeches and holding onto the lifts of the buoy.