Is No. 43 of this Journal we described and illustrated the portable " Roller Skids " on which life-boats are hauled out of the wafer prior to placing them on their carriages, and in the 59th number an improved self-lubri- cating roller for those skids and for the keel ways of the carriages on which the keels of the boats rest when placed on them.

On account of the great weight of life- boats, varying from 2 to 4J tons, it would be impossible to haul them over the ground or on to their carriages without some such contrivances, whilst the rapidly launching them from the latter into the water also much depends on whether the rollers on which they ran tarn freely and readily, whence the advantage of the self-lubricating rollers last referred to. These latter contain within them a small reservoir of oil which feeds the axle-bolt as the roller revolves round it, and which answer perfectly when kept in proper order and duly supplied with oil.

In practice, however, it has been found that, here and there, the supplying the rollers with oil in sufficient quantity is apt to be neglected, or that a bad description of oil is supplied which becomes sticky and clogs the rollers, requiring them to be taken out to be thoroughly cleaned and put to rights, which operation, as regards the rollers in the carriages, can only be per- formed when the boat is off the carriage.

Accordingly, to obviate this disadvantage, another description of roller of a more simple character has been designed, which, although it does not revolve quite so readily as the self-lubricating rollers, is, from its great simplicity and the ease with which it can be removed for examination and lubri- cation, more suited for life-boat work.

The following illustrations will serve to show the character of these rollers * which j would, no doubt, be found generally useful ' in hauling up large boats of any description on flat shores.

Fia. J.

Figure 1 represents a roller which is east solid, with two projecting axle-arms, on which it revolves.

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Figure 2 shows a portion of the inner face of one of the wooden side pieces form- ing the frame of a portable skid, or of the keelway of a carriage. In this frame, on either side, is sunk a groove, or slot, which when lined with a letter U-shaped iron lining of sufficient strength, corresponds in width and depth with the diameter and length of the axle-arms on the rollers, the bottom of the groove acting as a bed or matrix in which the corresponding axle-arm | revolves. I All the former descriptions of rollers were cast with a hole through their centre, through which ran a central axle-bolt pass- ing through the wooden sides of the keelway, or skid, upon which the rollers revolved.

But these bolts being secured by screw heads and nuts, which in time would get set fast with rust, the rollers were virtually fixtures.

The great advantage in this respect of the new rollers will be evident since, as they merely drop into place, their arms sliding up and down the iron-lined grooves, they can I grease being placed in the bottom of the be taken out and replaced at pleasure by i groove, they are at once lubricated for hand, and a small piece of tallow or other use.

FIG.

Figure 3 shows a section of the side frame of a skid, or keelway, and of a roller which will still further exemplify the position of the latter when placed ready for use.

As, however, when used in the portable skids, the rollers would be liable to fall out and be lost in the event of the skids being turned " upside down " when in use, it is necessary then to insert, at the top of the groove, a tight-fitting piece of wood to close the mouth of the groove, but which can be removed with little trouble when the rollers are required to be taken out.

Fig. 4.

Figure 4 shows a groove with a piece of wood thus inserted in it.

Skids of this description are now in use by the local boatmen on part of the coast of Suffolk, from whom we have copied them, and we can recommend their trial in other localities.