US11555A - Improvement in floating drags or anchors - Google Patents

Description

UNITED STATES PATENT OFFICE.

ABEL F. LEWIS, OF SI-IOPI-ERE, IVISCONSIN.

IMPROVEMENT IN FLOATING DRAGS OR ANCH ORS Specification forming part of Letters Patent No. 11,555, dated August 22,

To all whom, it may concern.-

Be it known that I, ABEL F. LEWIS, of Shopim'e, in the county of Rock and State of Wisconsin, have invented certain newand useful Improvements in Floating Drags or Anchors for Vessels, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings,in which- Figure 1 represents a vessel lying to in a gale of wind held by one of my improved anchors, where it is supposed there are no soundings within the length of a common cable. Fig. 2 represents a side and Fig. 3 an edge elevation, the black lines showing the anchor in a vertical position and the redlines showing it in an inclined position. I

This anchor may be made of any material possessed of the requisite strength and durability; but I prefer to make it of wood and metal in such proportions that the specific gravity of the anchor will be only so much greater than that of the water as is necessary to cause it to sink readily. It should be made of a size proportionate to that of the vessel for which it is intended, ten feet long and eight feet wide being about the proper dimensions for a vessel of seven hundred and fifty tons burden.

If the anchor were made wholly of metalor other similar weighty substance, it would require a buoy too large and cumbrous to keep it afloat.

, In constructing the float I take several nar row planks-say twelve inches wide and from two to three inches tl1ick-and I secure them together by metallic bars and hinges in such manner that any number of the plankscould be readily removed, if desired, or the whole taken apart. Near each corner of the anchor an eyebolt a is secured, from which a bracerope 1) extends to a thimble 2, connected bya swivel-link to the end of acable which reaches from the vessel. It is obvious that the anchor thus constructed and attached to the cable will, if the brace-ropes are of equal length, stand in a plane at right angles to the line in which the cable pulls, very muchin the same manner in which a kite is held at right angles, or thereabout, to the direction in which it is pulled by the line. By thus arranging the brace-ropes, making them of equal length and causing them to meet opposite the middle of the side of the anchor, the whole forms,

as it were, a skeleton pyramid, of which the anchor is the base, the hawser'ropes the angles, and the cable the axis.

The anchor is kept floating by means of a buoy c, with which it is connected by a cord (7, the lower part of which branches to the opposite ends of the upper edge of the anchor, where they are fastened to it by means of eyebolts and hooks or thimbles provided for the purpose.

If this anchor had to be hauled on board a vessel by the cable like a common anchor, it would be very difficult in all cases and in some almost impossible to effect the object, because of the great resistance which would be offered by the water to its movementbroadside first, and from itsgreat tendency to swing edgewise it would also be liable to stave thc planking of the vessels bow or be itself damaged by the concussion produced from this cause. To obviate this difficulty, I have attached to the upper edge of the anchor by an' eyebolt e what I term a canting, or hauling-in hawser, which passes through a thimbletnear the swivel. Under this arrangement the first thing to be done in taking in the anchor is to tighten the hawser f and to slacken the cable 9, which causes the anchor to cant and move edgewise towardthe surface of the water. It can now be hauled in edge first with comparative ease and withoutjliability to those dangerous lateral oscillations which would be developed if an attempt were made to haul it in broadside first.

The canting-line has anotherimportant use, which is to regulate the resisting power of the anchor to adapt it to different circumstances. The resistance which this anchor will oppose to the motion of the vessel, other circumstances being equal, will in allcases be inversely proportionate to the area which it opposes to the .direction of the pull of the cable. This resisting area will have a maximum development when the side of the anchor is perpendicular to the pull of the cable. Its minimum resisting power will be when the anchor is drawn edgewise through the water and its side is parallel to the pull of the cable, and its resisting power will vary with every degree of obliquity at which the anchor stands to the cable between these two extremes. For the purpose of rendering this principle available it is only necessary to the anchor.

tighten and slacken the hawserf.- Suppose that a vessel thus anchored in a gale of wind should not ride easily in consequence of being held too firmly, by tightening the hawser, as shown in Fig. 3 by red lines, the anchor will be inclined with its upper edge toward the vessel, diminishing its effective area of resistance, and thus holding the vessel more easily and permitting her to drift faster. If the anchor werein shallow water, it would also pass over obstructions at the bottom with less danger of being broken or entangled when thus inclined than if it were hung in a perpendicular position. When it is necessary to increase the resistance, this is readily done by slacking out the hawser, the whole being thus regulated and controlled from the vessel and with the utmost convenience.

Preparatory to casting this anchor the buoyline should be lengthened or shortened, according to the distance below the surface of the water at which it is required to suspend This distance will vary with the roughness and violence of the sea, it being desirable to suspend the anchor at barely sufficient depth to avoid disturbance from the commotion of the water, because the nearer the anchor is to the surface the more direct will be the pull of the vessel upon it and the less the liability to the alternate tightening and slackening of the cable, which when occurring produce violent surges, strains, and injuries to the vessel, cable, and anchor.

WVhen the anchor is lowered into the water, the buoy is thrown overboard and a sufficient length of cable let out to allow the vessel to ride easy.

When the anchor is raised from the water, it may be either hung at the ships bow or, if it is likely that it will not soon be again required for use, it maybe hauled aboard, taken to pieces, and the parts stowed away until -theanchor is again likely to be wanted.

. The anchor represented in the drawings is constructed of planks strengthened with bars 1' of wrought-iron, the whole firmly connected together by screw-bolts n, the bolts passing through both the planks 'm and iron bars. These planks are further strengthened by a series of iron cleats r, the adjacent ends of which may be made tubular and notched to interlap in the same manner as the two leaves of a butt-hinge, so that when a rods is passed through these tubular ends of the cleats it will interlock those of adjacent planks. The whole of the cleats being thus connected, they will mutually support each other, and the anchor will be greatly strengthened without having its weight materially increased.

Among the numerous advantages connected with my improved floating anchorthe following may be enumerated as the most prominent: It will keep a vessels head to the wind whenlyingtoa most important desideratum. It will materially lessen the drifting of vessels in a gale of wind,thus avoiding in agreat measure the danger of shipwreck on a lee shore. v It may be employed to retard the change of position, if so desired, of fishingvessels or of vessels discharging or taking in cargo. It will likewise often be found of great use in working vessels into harbors which have a narrow entrance and strong tidal currents. For example, suppose the current setting into a harbor to be three miles an hour and the wind blowing directly out of the harbor with a force sufficient to drift a sailing-vessel that wants to enter three and a quarter miles an hour, the mouth of the harbor being too narrow for the vessel to beat in. It is plain that with all ordinary appliances she could not enter; but by throwing overboard one of these anchors it would quickly tow her in by the force of the current ABEL F. LEWIS.

Witnesses:

P. H. lVATsoN, F. G. FONTAINE.

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