hawser. The two towing hawsers are shackled together, and payed out. When the chain bridle is reached (on the towed ship) it is payed out carefully and the two cables are veered away to whatever scope is considered advisable. Sixty fathoms

is recommended.

The precautions to be observed in starting ahead and in increasing speed have been detailed in an earlier part of this Chapter.

§ IV. TOWING ENGINES. TOWING ALONGSIDE.

Towing Engines. In the United States, vessels designed especially for towing are in most cases fitted with towing-engines, which carry the line on a reel and pay out and haul in automatically as may be necessary to keep the tension constant; the resistance of the tow being borne entirely by the steam pressure in the cylinders. If the tension on the hawser rises momentarily above this steam pressure, the drum revolves and pays out line. This action opens the regulating valve and increases the steam pressure in the cylinders until this pressure balances the tension on the line. If, later, the tension decreases, the steam pressure will be in excess and the drum will revolve and reel in the line, but at the same time the regulating valve will close in part, and the pressure will fall until it meets and balances the tension. In this way, the line is paid out or reeled in only just enough to meet the condition of things prevailing at any given moment, and the average length of line remains practically constant.

There can be no question of the enormous advantage in towing resulting from the use of these engines. A point of great, though perhaps secondary, importance, is that if the towing vessel stops, or if for any other reason the tow ranges up and slacks the line, the engine takes in the slack at once and keeps it clear of the screw. If it is found desirable at any time to shorten in the line, reducing the distance between the vessels, it can be done without difficulty. This may be important in passing around bends in a channel, or for taking in the line preparatory to casting off.

It is not the least of the advantages of the towing engine that it makes the use of wire-rope perfectly safe in all weathers.

Towing Alongside. When towing in port or in confined waters, the tug should be made fast alongside if possible, as this gives

greater ease and certainty in handling. When used in this way, the tug is usually placed on the quarter, where its rudder acts with that of the tow, for steering. As the power is applied at a distance from the midship line, there is here a considerable turning moment, which will throw the ship's head to one side or the other, according as the tug goes ahead or backs; the effect being exactly as if the ship had twin screws and was using only one of them. In going straight ahead, the turning effect is neutralized by a small amount of helm.

The tug must be made fast with a line from aft for going ahead and one from forward for backing. Both of these lines are usually made fast at the bow of the tug, her stern being held from swinging out by a breast-fast leading to the tow (Plate 122).

If the tug has a right-handed screw, she will handle better if made fast on the port side; since, in backing, the tendency of her screw is to throw her stern out to port, while the tendency due to her position on the port side of the tow is to throw the stern of the tow the other way. Thus she will make a straighter sternboard than if made fast to the starboard side, where both these elements would tend to throw the stern off to port.

If, however, there is a sharp and difficult turn to be made, the tug should be on the inboard quarter; that is to say, on the side toward which the turn is to be made. Here she will be properly placed for backing to assist in the turn. So long as she is going ahead, she would be more favorably placed for turning, on the outboard side; but if her turning effect when so placed should prove insufficient for the turn she would be helpless. To back, under these circumstances, even for keeping clear of the beach, would only make matters worse. It is, therefore, the practice of tug masters to place themselves on that side of the tow toward which they wish to turn, if the turn is one which involves some difficulty.

It sometimes becomes necessary to turn the larger vessel on a pivot; that is to say, without going materially either ahead or astern. Suppose the tug is on the starboard quarter and wishes to slew the stern of the tow to port (Plate 117). She lets go

her stern breast and goes ahead with starboard helm,2 holding on to the "go-ahead" line. This throws her stern out and she puts her bow (usually protected by a good fender) against the stern of the tow and pushes it around.

2. left rudder.

If it is desired to pull the stern to starboard, she lets go both lines from her bow, slacks the after-line, and swings off clear, going ahead as in Fig. 8. Observe that for this manœuver it is necessary that the line used for towing should lead from a point on the tug far enough forward of the rudder to let the tug's stern swing freely. She will then be able to head in any direction desired, even though there may be a current setting her down.

This is perfectly simple in the case of a tug whose towing bitts are placed well forward as is usual with tugs. In the case of a vessel not fitted in this way, the line may be taken through a sidechock fairly well forward, the vessel in this case being held up by the helm as in Fig. 2, Plate 148.

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It sometimes happens that a vessel towing another alongside wishes to wind" the tow to put her alongside a dock, the side on which the towing vessel is secured being the side which must be put to the dock. This is a manoeuver which may be seen almost any day in a harbor like New York, where a tug, towing a barge and having the barge, say, on her starboard side, wishes to land the barge alongside a dock which is on the port hand, and at the same time to get herself clear of her position between the barge and the dock. Plate 117 makes it clear how this manoeuver is performed. (But see description in Chapter XV.)

CHAPTER XXII.

RESCUING THE CREW OF A WRECK.

The situation here is somewhat like that where one ship is to take another in tow, but with several important points of difference. No matter how bad the weather may be, the work of rescue, if it is to be attempted at all, must usually be undertaken at once; and in practically all cases, by means of a boat. On the other hand, the rescuing ship is much freer to manœuvre than when she is hampered by lines as in making preparations for towing.

The natural way of proceeding under ordinary circumstances is to go to windward of the wreck and lower a boat, then go to leeward and stand by to pick it up. If oil is used along the weather side of the wreck, the boat will have an oil-slick, in addition to the lee afforded by her own vessel; and if the rescuing vessel uses oil after getting into position to leeward, the slick may be continued so that the boat shall have the benefit of it as she returns, loaded, before the sea. If for any reason the wreck cannot use oil, the rescuing vessel can steam around her, running oil freely and so creating a slick into which the wreck will presently drift.

If the weather is very rough, extreme precautions will be called for in lowering the boat and getting her clear. The ship should be held up with the sea on the bow, giving a lee for the boat and reducing the rolling as much as possible. The crew is lowered in the boat, with life-belts on. A painter is used from well forward, brought in on the inboard bow of the boat and tended with a turn around a thwart, and the steering oar is shipped in its crutch, ready to assist in sheering off clear of the side as soon as the boat is in the water. Frapping lines may be used around the falls to steady the boat, and sails or mattresses hung over the side as fenders, to prevent the boat from being stove if she swings in heavily. Two or three extra life-belts should be taken along, with two heaving lines bent to each. These are