The “Kabelveerpont” is another kind of boat for crossing streams. The swinging cable is here replaced by one which crosses the stream, on the bottom of which it lies under the action of its own weight. The middle of the upstream side of the boat is attached to this cable, which passes over a sheave. In order to cross the stream, the boat is pushed off into the current, after having raised the movable bridges, then the cable is drawn up on the end of the boat pointing across the river and made to pass over a sheave placed, temporarily and for the crossing, at the middle of the bridge. The pontoon then occupies a position oblique to the cable and, as in the preceding case, at an angle to the direction of the current which causes the boat to move. The cable, which runs from one bank to the other, rests on the bed of the river from which only the part on the boat is raised. The pontoons serving the crossings at Kessenich-Stevensweert and at Elsloo-Boorsheim (Limburg-an-Meuse) may be mentioned as examples of this kind of ferries. The cable is not always raised, however, on the boat because when so raised it may interfere with navigation. Sometimes the cable is allowed to remain on the bed of the river and the ferry is attached to a rope which is connected with the cable by means of a roller. This rope, which is then stretched in the direction of the current, is fastened to the middle of the upstream side of the boat. If now the latter be inclined by means of a special cable, as explained in the case of the “Gierpont”, it crosses the river, the roller running on the cable which lies on the bottom. An example of such a boat is to be found at the crossing at Zalt-Bommel in Gelderland. The trouble with these cables and of all transverse cables in general is that they are often displaced by the anchors of vessels which foul them in passing. Abroad, especially in Belgium, the cables for trail bridges (as they are called in the United States) are stretched above the river so that vessels can pass underneath. But this arrangement does not seem to be applicable to heavy boats and to the great widths of the crossings found in Holland without using expensive means for supporting the cable. In Limburg, where the character of the Meuse is torrential, and where the steep slope of the bed causes much more violent currents than in the rest of our country, the barges have no lee boards. A very wide approach ramp is necessary for all these ferries in general and for the “Kabelveerponten” in particular. A width of 16 metres at the level of mean low water and lessening upward has been found necessary, because of the slack of the cable which varies with the strength of the current and the force of the wind. The more violent the current, the easier it is to go safely on the boat, and this allows the width of the approach ramp to be reduced near the top, because this upper part is only utilized during high water. [Sidenote: III 174] [Sidenote: III 175]