GB2297625A - Vector triangle plotting device - Google Patents

Abstract

A vector triangle plotting device for use on a navigation chart so as to mechanically construct a triangle full size to the scale of the chart and without having to draw any lines on the chart itself comprises three slides 101, 102, 103 each representing one of the vectors used in navigational plotting, namely tidal stream or wind drift, course required (ground track), and the course to steer / heading (water track) for either sea-going or air-going vehicles. The slides are connected to each other by sliders 104, 108, 118 to allow each slide to freely move about each other along their complete lengths and also able to be locked into any position thus representing the length of each vector.

Description

DEVICE FOR MECRANICALLY CONSTRUCTING VECTORS FULL CHART SCALE SIZE AND THEN ALSO A VECTOR TRIANGLE TO FULL CHART SCALE SIZE ON A CHART To DETERMINE EITHER AN ESTIMATED POSITION OR A COURSE TO STEER FOR A SEA -GOING VESSEL OR AIR - GOING VEHICLE WITHOUT HAVING TO DRAW ANY LINES ON THE CHART ITSELF.

BACKGROUND A course to steer usually needs to be determined at least once an hour to modify the heading of a vessel to compensate for the speed and direction of the tidal current acting on it during this particular period so as to ensure that the vessel ill make the course as intended.

This is normally carried out by drawing a stencil line on an Admiralty Chart, or others used it: navigatIon1 renresenting the course the vessel ns reu-ired to travel, then by drawing a second line in a direction representing the tidal current, or in the case of an air - going vehicle the wired refers.

A distance representing the vessel's steed is then normally measured off between the end of the second line drawn and the first line drawn.

Where this point is reached on the first line then allows a vector triangle to be drawn on the Chart inorder to measure actual distance travelled and the heading or course to steer.

Alternatively an estimated position has to be determined for the vessel by dead reckoning Here a line is normally drawn on the Chart to represent th direction and steed of the tidal current from the vessel's current position, followed by the drawing of a second line in the direction of and to the distance the vessel has travelled over a one hour period of time. The end of the second line drawn on the Chart thus gives the estimated position of the vessel or vehicle.

This invention hereby described alleviated the need to draw any'such lines on a Chart in both these cases.

SUMMARY OF THE INVENTION This invention relates to a device to enable the physical mechanical construction vectors and the vector triangle used innrvigation, full size to a Chart's latitude scale, regardless of the scale dimensions, without having to physically draw any lines on the Chart itself.

The three vectors so constructed in the triangle can represent the set and drift of the tide or wind, the course to which the vessel is required to go and the heading or course to steer. The device is able to be used for either sea-going or air-going vehicles.

The dtvice can be used in two different ways either to estiblish the required course to steer (heading) or the estimated position of the vessel.

The device consists of three slides or rulers which can be either flat nr round in shape and of any length, interconnected by sliders able to be locked into position anywhere along the length of each slide or ruler, and Din tyte connections, all used in conjuntion with a standard 360 degree protractor or by using the printed compass rose on an Admiralty chart or others,such that when the said device is adjusted with each slider set into position and the angles set between each slide or ruler, the device can be layed onto the said chart and either the course to steer(heading) or the vessel's estimated position can be represented over the chart without having to plot and draw any lines on the chart itself.

This device is therefore a simple and quick apparatus for carrying out the above mentioned procedure and particularly useful when a vessel is in trough sea conditions(or wind conditions) where it is found difficult to actually draw any lines on navigational charts and especially when the vessel is close to shore when there is very little time available to carry out drawing work on charts.

Currently Tidal doc*amer.ts are readily available such as a Tidal Atlas showing specific tidal information for direction and steed of the tidal current in a maD form for every hour before and after rig tide, otherwise known as high water. These are normally shown on serrate individual diagrams for each hour before and after high water and this invention has the advantage of being able to set up with this tidal information by simply being layed over such a tidal atlas and locking the device accordingly.

This device can also be easily adapted for attachment to a standard zantograch and plotting board apparatus with or without electronic control.

DESCRIPTION OF TRE DRAWINGS AsDecific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: FIG 1 shows in plan view the general arrangement and main components of the vector triangle plotting device.

FIG la sows a pictorial view of an optional flit down cursor FIG 2 is a sectional view cf slider 'A' as shown through section x-x in the side elevation view in FIG 5.

FIu 3 is a sectional view of the rivet marker as shown through section y-y in the side elevation view in FIG 5.

FIG 4 is a sectional view of slider 'B' as shown through section z-z in the side elevation view in FIG 5.

FIG 5 is a side elevation of the vector triangle plotting device.

FIG 6 shows a pictorial view of an alternative modified arrangement without a protractor fitted for use on small scale charts.

DDSCRIPTIOis OF EMBCDIMEiÇT According to the present invention there is provided a device which comDrises of three clear plastic slides or rulers but can be made from any other material, connected to each other by means of sliders and or tin type fasteners and with one of the sliders attached to a standard Protractor item 106 which can be either square or circular in shape graduated 360 degrees. FIG. 1 and FIG. 5 refer.

Each of the slides or rulers represents one of the three vectors necessary in producing a navigational vector triangle such as for the course (i.e. track over the ground), tidal set and drift (or wind), and course to steer (heading).

Tne Tidal Stream Ruler item 101 is named as the slide or ruler for representing the tidal set and drift (or wind) and has a slider connect to it named Slider 'A' item 104, which is free to slide along the Tidal Stream Ruler item 101, but able to be locked into any position by a screw item 105, referred to as Screw 'A'. The Slider 'A' item 104 is also connected to the Protractor item 10 by means of a pin tyte fastener such as a Rivet item 113 o one side. FIG.l and FIG.2 refer.

The Course to Steer Ruler item 102 is named as the slide or ruler for representing the course to steer vector for the vessel and is connected at one end to Screw 'A' item 105 and at its other end to a double slider item 108 and 118 which shall be named Slider 'B'. This Slider 'B' is also freely able to slide along the Course to Steer Ruler item 102 but able to be locked into any position along the ruler by a screw item 109 which shall be named as Screw 'B'. FIG.1 and FIG.4 refer.

The Course Ruler item 103 is named as the slide or ruler for representing the vector of the course which the vessel is taking and is connected at one end through the Slider 'B' item 109 Such as to be able to freely allow the Slider 'B' to move along it's length at all times. The opposite end of the Course Ruler is enecte to one end of the Tidal Stream Ruler item 101 by a pin type fastener item 112 such as a rivet and although fastened are still free to rotate about each other. There is a marker item 115 located under the rivet to permit the marking of a chart and there is a hole item 116 provided in the top of the rivet for the location of Dividers should these be used.

This shall be named as the Rivet Marker. FIG.3 refers.

It should be noted that there is a further marker item 119 shown on FIG.4 attached to the Slider item 118 also Drovided for marking a vessel's position on a chart and that the double Slider 'B' is in fact made from two separate sliders item 108 and item 118 connected to each other by a pin type fastener item 117 such that each is able to freely rotate about one another.

To tlot the Course to Steer then, the steed of the tide known as tidal drift is represented by adjusting the device to give a distance or dimensio. between the centre of the Rivet Marker item 112 and the centre of Screw 'A' item 105. This is achieved by means of either laying te Tidal Stream Ruler item 101 along the latitude scale on the Chart or using a pair of standard Dividers by locating the points of the Dividers in hole item 116 provided in the top of Rivet Marker item 112 and the hole item 114 in Screw 'A' item 105. Screw 'A' then being tightened thus locking Slider 'A' item 1Q4 into the set position along the Ruler item 101.

Zne speed of the vessel or vehicle is represented by adjusting the device to give a distance between the centre of Screw 'A' item 105 and Strew 'B' item 109 along the Course to Steer Ruler item 102 again by either laying along the latitude scale on the Chart or by taking off the dimension from the Chart's scale using the pair of standard Dividers with the Dividers points located into hole item 114 and hole item 122.Screw 'B' then being tightened thus locking Slider 'B' item 108 and 118 into the set position The Protractor item 106 is then rotated round until the required tidal. set angle aligns with the marker line item 107 running down the centre of the Tidal Stream Ruler item 101 (wind direction applies in the case of an air-going vehicle) or alternatively by laying the device over the relevant page in a Tidal Atlas or local tidal map and lining up the direction of the tide given in this document with the Tidal Stream Ruler relative to the Protractor item 106 being placed squarely on the page and facing North in direction.

The device is then layed down over the Chart with the Rivet Marker item 115 over the veBsel's or vehicle's current position and the whole complete device moved or swung round so as the Protractor item 106 is positioned squarely and facing. North on the Chart itself, i.e. the grid lines on the protractor align witt like lines on the Chart.

with both Rivet Marker item 115 and te Protractor item 106 firmly held down on the Chart, Slider 'B' item 108/118 is swung round so as the Course Ruler item 103 faces in the direction the vessel is required to go using the marker line item 111 running down the centre of the rulertself as an accurate viewirg line in order to ensure that the intended course for the vessel will not cause the vessel to travel near or onto any hazards as shown on the Chart such as ship wrecks, sand banks and such like.

The course to steer or beading is then simply read from the value on the Protractor item 106 nearest to where it aligns with the marker line item 11C running down the centre of the Course to Steer Ruler item 102 and any variation required to convert this reading from in degree True to degrees Magnetic car. be obtained by using the east or west secondary graduations item 121 running either side of the main marker line item 110 on the Course to Steer Ruler.

The new position of the vessel is marked on rhe Chart by means of pressing down Slider 'B' item 108/118 which leaves a small imprint on she Chart by item 119 integral marker attached under Slider 'B' item 108/ 118. The mark on the Chart can be further highlighted by adding a pencil dot if so desired.

Item 102 and an alternative arrangement is also provided as illustrated pictorially in FIG la whereby a clear plastic Cursor item 122 is provided to transfer graduation markings from 102 down to align with graduation markings on the Protractor item 106, by a flap item 123 being hinged by pin item 124 such as to allow this flap to be retracted up into the Cursor and be clear OJ items 101 to 103 when these are rotated, yet able to be hinged down when accurate readings are required.

To plot anest-imatea position by dead reckoning the device is set up in a similar manner as previously described in paragraphs 4 and 5 on page 3 and paragraph 1 on page 4, i.e to ensure that screw 'A' item 105 is locked at a distance from the Rivet Marker item 112 to represent the tidal drift, that screw 'B' item 109 isa distance from screw 'A' representing the speed of the vessel and that the Protractor item 106 is set at the angle to represent the direction of the tide or wind in the case of air-going vehicles.

Still with the Protractor set to item 101 to represent the tidal condition, the Course to Steer Ruler item 102 is swung round so as the marker line item 110 aligns with a value on the scale of the Protractor item 106 corresponding to the current course which the vessel is heading on but this time using the reciprocal value by 180 degrees of this heading onto the graduations on the Protractor. Due account is made to ensure the values are in degrees True.

The device is tnen layed onto the chart so as the screw 'B' marker item 119 is directly at the vessel's current position on the chart and held in this position whilst the whole complete devise is swung round so as the Protractor item 106 faces North by the alignment of the grid lines on the Protractor with the corresponding grid lines on the chart.

The Rivet Marker item 115 is pressed down thus making a mark on the chart which is the estimated position of the vessel and can also be highlighted further by the addition of a pencil dot on the indund o on the chart if so desired.

An alternative modified arrangeaent of the device is now described for use on small scale charts such as those used on ocean charts and ocean passages of where plotting is required to be executed over short spaces of time between plots carried out.

This alternative modified arrangement is shown pictorially in FIG 6 whereby the slides or rulers items 101 - 103 comprise of small diameter rods or bars made of steel, brass or any other material and the sliders items 104, 108 and 118 consist of blocks with holes passing through.

In this device there is an additional location pin item 130 which is used to locate on the centre point item 131 of the compass rose item 132 on the chart item 134 itself and here in this the use of the Protractor item 106 is not required.

There is also a pointing rod or bar item 133 which is attached to the slider item 104 in lieu of the Protractor item 106 and is used as a North pointer and set to zero degrees/North on the compass rose. The tidal slide or ruler item 101 is also set up using the compass rose in-lieu of the Protractor item 106 after first carrying out a similar procedure as previously mentioned in paragraphs 4 and 5 on page 3 of this specification.

The device is then moved across the chart so as the rivet marker item 115 is on the current position of the vessel, then the whole complete device is swung round so as the pointer item 133 faces North on the chart so as to be parallel with the vertical grid lines of the chart. (A Douglas protractor can be used to assist in this).

Holding both items 115 and 133 in position on the chart, the course slide is swung round to the direction the vessel is required to go.

The devise is then t;iansferred back over the compass rose item 132 printed on the chart, again aligning the item 133 to North, and the angle the course to steer slide item 102 makes over the rose is the course to steer the vessel so allowing for tidal set and drift of the tidal stream or heading.

Claims (5)

1 A vector triangle plotting device comprising of three slides or rulers each representing one of the three vectors used 1: plotting a vector triangle on a navigation chart, namely the tidal stream eet ( nr wind), the course of the vessel or vehicle and the course to steer (or heading) for a vessel so as to to be able to mechanically construct the said slides or rulers into a vector triangle, fll size to the scale of the chart (normally the latitude scale), without having to draw any lines on the chart itself, inorder to determine either a course to steer or estimated ? sition .

2 A vector triangle plotting device as claimed in Claim 7 wherein the device is able to be used without calculations,or the lse of multi circular rotating discs whereby the said device links together each of the three sliders or rulers together by sliders able to freely move along the length of each slide or ruler but able to be locked to any position, the distance between each representing the speed of either the tidal stream (or wind), ground track or water track (speed through the water or air).

3 A vector triangle plotting device as claimed in Claims 1 or Claims 2 wherein marker lines running down the centre on each slime or ruler along it's complete length represent the lines of te vector triangle if this item was otherwise drawn on a chart to full scale size.

4 A vector triangle plotting device as claimed in Claim 1 or Claim 2 or Claim 3 wherein each slider in addition to being able to move along the length of the slide or ruler is also able to freely rotate about either a second slider connected to it by a pin type fastener such as a rivet or shaft, and that when said slides pass through each of the sliders they too are able to both rotate around each other in ary direction about the pin type fastener. In addition to this the slider is able to move along the length of the slide or ruler and itself able to be connected to the end of a second slide or ruler by pir type fastener or other means to allow both the said slides or rulers to freely rotate about each other. In addition to this a standard 360 degree protractor can be connected to a slider by a pin type fastener such as a rivet and free to rotate and that the assembled slider, with the protractor attached, is able to move along the length of a slide or ruler.

5 A vector triangle plotting device as Claimed in any preceding claim wherein the device can have a flap down hinged cursor over the slide or ruler, as an attachment able to freely move along the slide to transfer graduation markings from the slide down to be aligned and read off against graduation markings on either another slide or a protractor. The whole complete device is able to be fitted to a standard commercially available pantograph system itself fitted to a standard plotting board.