Boys' Book of Model Boats Part 10

[Ill.u.s.tration: FIG. 139]

The ketch rig differs greatly from the yawl rig. The mizzenmast always occupies a position forward of the rudder-post. In the yawl the mizzenmast is always stepped aft of the rudder-post. This will be seen by referring to the drawings of the two boats. The ketch rig is ill.u.s.trated in Fig. 139.

The prettiest rig of all is the schooner; but, owing to the fact that it is difficult to get them to go well to windward unless the hull is perfectly rigged, the author has decided not to deal with this type of boat. When the reader becomes proficient in building and sailing the simpler types described in this book, he may turn his attention to the construction and sailing of more complicated types.

_Model Yacht Parts_

The submerged portion of a yacht is, as in all other boats, termed the hull. The backbone of the hull is called the keelson. Attached to the keelson is a piece of lead, which is put in place to give the boat stability and power to resist the heeling movement created by the wind-pressure upon the sails. This is known as the keel.

Yachts always have an opening in the deck giving access to the interior of the hull. These openings are known as hatchways. When sailing in rough weather the hatchway is closed by a hatch to prevent the yacht from shipping water.

The extreme forward end of a yacht hull is called the stern, while the portions forward and aft of the midships section are known as the fore and after-body respectively.

[Ill.u.s.tration: A TWIN CYLINDER STEAM ENGINE FOR MODEL MARINE USE

This engine will drive a boat several feet long]

In all yachts a portion of the hull extends out over the water. These portions are known as overhangs. The overhang aft is sometimes called the counter-stern. The sides of the hull that rise above the deck are called bulwarks, and the part of the bulwarks that cross the stern is called the taffrail. The taffrail is always pierced with holes to allow water to run off the deck quickly, so that the additional weight will not in any way affect the course of the boat. It is understood that yachts raise great quant.i.ties of water upon their decks when traveling in rough sea.

The bowsprit is pa.s.sed through a ring at the top of the stern, and this ring is termed the gammon iron. Its end is secured in a socket or between a pair of uprights called the bowsprit bits. These are fixed to the deck. Metal bars are fixed a short distance above the deck to take rings attached to the sheets. This is done so that the sails may swing freely from one side of the boat to the other. Metal eyes are screwed into the sides to take the shrouds, and are called chain-plates. The eye in the stern is called the bobstay plate. In the stern-post are two eyes called gudgeons. The rudder is hooked to this by means of two hooks called pintles. The bar or lever that is fixed to the top of the rudder-post is called a tiller.

[Ill.u.s.tration: A CUP-WINNING MODEL SAIL BOAT

Designed and constructed by the commodore of the Central Park Model Yacht Club, New York, N. Y.]

The parts and fittings of a mast follow: the step, the head, the caps, crosstrees, truck, topmast, boom, and gaff. The part of the gaff that rests on the mast is called the throat; the end of the gaff is called the peak. The jib-boom is a term used only in connection with model yachts. In larger boats the jib-boom is an extension of the bowsprit.

The small boom that projects over the stern of a yawl is called the b.u.mpkin. The spar is rather a general term applied to practically all wooden supports of sails. The spar of a lug-sail is called the yard. It is different from a boom or gaff, by reason of its lying against the mast instead of having one end b.u.t.ting on the mast. Anything belonging to the mainmast should be distinguished by the prefix main. Thus, there are the mainsail, the mainboom, main-topsail, etc.

[Ill.u.s.tration: FIG. 140]

A sail for a model cutter-rigged yacht is shown in Fig. 140. The bowsprit and masts are, when necessary, given support by ropes that are stretched tightly to some point where they can be conveniently anch.o.r.ed to the hull. The following are those largely used on model yachts: topmast stay, bobstay, topmast shrouds, and forestay.

The sails are pulled up and fastened by ropes termed halyards. The halyards are fastened to the upper portions of the sail, and they are named according to the sail to which they are attached. For instance, there is the jib halyard and the foresail halyard. A mainsail carried by a gaff has two halyards, the throat and peak. The movement of the sails is controlled by ropes, called sheets, which take their names from the sails they control. There is a mainsheet, a jibsheet, and a foresheet.

The reader should take note of this term and refrain from confusing it with the sails.

_Sailing Model Yachts_

The sailing of model yachts is a real art, and the author warns the reader that he cannot hope to become a proficient yachtsman by merely digesting the information given in this book. His real knowledge must be earned by experience in handling a model yacht on the water. However, there are few sports that will afford more pleasure than that of sailing model yachts. Being an outdoor sport it is very healthful.

In sailing a model yacht the sails are set, or "trimmed," so that she will continue to sail along the course previously decided upon by the yachtsman. She must do this in as speedy a manner as possible and with as little deviation from her original course as possible. The trim of the sails will depend upon the wind. If the boat is to sail against the wind, that is termed "beating to windward"; with the wind is called "scudding." With the wind sideways it is called "reaching." If the boat is sailed with the wind blowing midway between one of the sides and the stern in such a way that it sweeps from one side of the stern across the deck, this is called "three-quarter sailing" in a "quartering" wind. A model yacht will continue for a great distance on a reach or while scudding; but, on the other hand, it will not be possible for her to sail directly against the wind. If a yachtsman is to make headway against the wind, he must sail his boat as near dead against the wind as it will go.

The cutter type of yacht will move against a wind that is blowing at a very small angle on her bowsprit. As soon as she reaches the limit of her course, the yachtsman turns her bow at a small angle so as to bring the wind on the opposite side of the vessel, and in this way a second course is started. These courses are repeated in a zigzag fashion until the yacht arrives at her destination. This zigzagging, or "tacking," as it is called, is ill.u.s.trated in Fig. 141. It will be seen that the yacht starts at _B_, and makes 3 tacks before she arrives at her destination, _A_. Each time she touches the sh.o.r.e she is "put about" and set upon a new course, or "tack."

[Ill.u.s.tration: FIG. 141]

It will be understood that tacking is slow work, and a greater distance must be traveled than would be covered by a power-boat, which would be able to go in a straight line. However, with wind-propelled craft this is the only way in which progress can be made against the wind. The left-hand side of a yacht viewed from the stern is called the port side, while the right-hand side is called the starboard side. Thus a yacht sailing with the wind blowing on her port side is on the port tack, while if the wind is blowing on the starboard side she is said to be on the starboard tack. From this the reader will see that Fig. 142 shows an impossible case.

[Ill.u.s.tration: FIG. 142]

[Ill.u.s.tration: FIG. 143]

[Ill.u.s.tration: FIG. 144]

[Ill.u.s.tration: FIG. 145]

The sails in front of the mast that are placed nearest the stern of the yacht act in such a manner as to turn the bows in the direction of the arrow, as ill.u.s.trated in Fig. 146, and the sail or sails abaft the mast turn the boat in the direction of the arrow _A_. The boat thus revolves upon the center of the mast much as a weatherc.o.c.k revolves upon its pivot. If there is more than one mast, all the sails carried abaft the mainmast serve to turn the boat in the direction _A_. The work of sailing depends greatly upon the skill in balancing these two effects so that the boat will progress in a straight line. To do this the sails are set in a greater or less angle in relation to the center line of the boat. The less the angle that a sail makes with the center line of the boat, the greater is its power to determine in which direction the boat will steer. The more the yachtsman slackens out his jib and foresail, or the smaller he makes these sails, the less their power will be to turn the boat in the direction _B_. On the other hand, the larger they are and the more tightly they are pulled in, the greater will be their power. When the mainsail and all of the sails abaft the mainsail are slackened out and the smaller they are made, the less their power will be to swing the boat in the direction _A_.

The influence of a sail upon the speed of a boat also increases with the angle that it makes with the center line of the hull. The more the yachtsman slackens out his sail, the more it will help the boat along.

The reader will see that these two conditions interfere with each other, and therefore the tr.i.m.m.i.n.g of the sails becomes a compromise. It is good for the young yachtsman to remember to sail his boat with the sails as slack as possible, as long as she keeps a good course. He should also remember not to overload her with sails, since the nearer to an upright position she maintains the faster she will go.

It is not possible to depend entirely upon the trim of the sails to keep a model in a given course. This is because the strength of the wind varies so that the sails are in balance one moment and out of balance the next. The sails abaft the mainmast overpower the sails before it when the wind increases. The result of this is that the bow of the boat will be repeatedly turned in the direction _A_, Fig. 146.

[Ill.u.s.tration: FIG. 146]

[Ill.u.s.tration: FIG. 147]

[Ill.u.s.tration: FIG. 148]

Some form of automatic rudder is therefore generally used to overcome this tendency of the yacht to "luff" in the wind. Fig. 147 shows the course of a yacht reaching from _A_ to _B_. The dotted lines show the course she should follow. The full line shows the effect of puffs of wind, which repeatedly take her out of her course. Many times she may completely turn around and make a similar course back to the starting-point, as in Fig. 148. There is also the danger of her being taken back when pointing directly against the wind--the wind will force her backward stern first for some distance, as ill.u.s.trated in Fig. 149.

She will do this until she manages to get around on one tack or the other.

The dotted line _B_ ill.u.s.trates the course in which she would be driven under these conditions. It is not practical to sail a model yacht dead before the wind without an automatic rudder. With the use of an automatic rudder the erratic movements shown in Fig. 148 can be entirely overcome. The action of the rudder is such that every time the boat leans over to luff up into the wind, the weight of the rudder causes it to swing out, and thus prevents her from losing her course. As a different type of rudder is required, according to the course in which the yacht is sailing, the weight should be adjustable if the same rudder is used.

[Ill.u.s.tration: FIG. 149]

[Ill.u.s.tration: FIG. 150]

[Ill.u.s.tration: FIG. 152]

Let us consider scudding before the wind. For scudding the heaviest rudder should be used, or the weight on a loaded tiller should be in its position of maximum power. All the sails abaft the foremast should be slackened out as far as they will go, which will bring the booms almost at right angles with the center line of the boat. If the craft is a cutter or yawl with a light weight, the yachtsman should rig the spinnaker. The head-sails may be left slack or can be tightened. Fig.

150 shows the position of the booms when scudding with a schooner and yawl. The yawl is shown scudding goose winged. The cutter is ill.u.s.trated with the spinnaker set. The other craft is a two-mast lugger with balanced lugs.

[Ill.u.s.tration: FIG. 151]

Attention is now directed to "reaching." For this particular work the yachtsman should put on a medium rudder. When using a weighted tiller the weight should be put in a midway position. The head-sails should be pulled in fairly tight and the aft-sails made slack. The yachtsman, however, should not slacken them as for scudding. Fig. 151 shows a schooner reaching. The thick black lines represent the booms of the sails. If the wind is very light a spinnaker-jib may be set or a jib-topsail in light or moderate breezes. In the case of a wind that comes over the stern quarter, as indicated by the arrow _A_, the next heavier rudder, or its equivalent in weighted tiller, should be put in operation, and the sails slackened out a little more than before. The boat is then said to be free and sailing on the starboard tack. If the wind is coming in the direction _B_ the jib and foresail may require slackening and the aft sails pulled in more than when sailing with the wind in the direction _C_. A still lighter rudder can be used as the course gets near to beating windward, and the yacht is said to be close-hauled on the starboard tack.

In beating to windward, if a rudder is used at all, it should be as light as possible, just heavy enough to keep the boat steady. However, this is just the condition of sailing when a boat can dispense with a rudder. It depends entirely upon the characteristics of the particular yacht being sailed, and for this the yachtsman must depend upon his own experience. The jib-topsail should not be used in a case like this, and if the wind is fairly strong a smaller jib should be set than that used for reaching. It is advisable to slacken the jib and foresail out and pull the aft-sails in somewhat tightly. Fig. 152 shows a cutter beating to windward on a port tack. In this case she will have to pay out to starboard a bit before her sails fill.

In sailing the weather must be watched very closely, and the amount of sail carried will depend entirely upon the weather conditions. A yacht should never be overloaded with sail. If she has more than she can comfortably carry she will heel over and drag her sails in the water.

Not only this, but she will also drift to leeward when beating to windward. When sailing a new boat, her best trim for various points of sailing and force of wind must be found by painstaking experiments. The boat should always be sailed with her sails as slack as she will take them and keep in her course. In this way she will move faster than when the sails are pulled in close.

The model yachtsman should always watch the wind and note whether it shifts its direction or alters its force. The boat is trimmed accordingly when the boat is put about. Easing or tightening the jib or main-sheet slightly will make a very noticeable difference.

By taking down the top-sail or setting a jib-head top-sail in place of a jack yard top-sail, the yacht will be caused to ride easier in puffs of wind. In case she does not point well to windward when beating, the yachtsman should try a smaller jib, or he can slacken the foresail-sheet. If she runs off regularly to leeward on one tack only, while keeping well to windward on the other, she has some defect in construction or a bent keel.