Typical mast partners are shown in Fig. 129. They are not fitted until the beams have been sprung to the full camber. One of the best methods of obtaining the correct shape of the upper and lower faces of the partners so that they will fit the camber of the beams is to scribe the partner mold direct from the beams after they have been sprung.

Masts are not set square with the keel, but generally rake aft from ¬ inch to ⅜ inch to the foot of height. It is necessary therefore before the partners are in place to set a line on the centerlines of the mast and ship, extending from the location of the mast step on top of the keelsons, past all of the decks and having the desired rake with the keel. If the tops of the keelsons are parallel with the keel the rake may be measured from the keelsons. An ordinary carpenter's chalk line may be used for this purpose and care must be taken to see that it is set in exactly the position that would be occupied by the center of the mast.

By measuring the distances from this line to the beams, at both the upper and lower faces, the proper location and bevel of the mast hole is obtained. This will not necessarily center on the joint between the partners.

The preliminary hole cut in the partners is usually much smaller than that finally required for the mast. If sufficient care is taken in locating the centers, the holes may be cut to within about one inch of the final diameter, and this may be done either before or after the partners have been fastened in place. The final diameter will be that of the mast plus the room required for the wedges.

The bolts fastening the partners should pass through beam and beam and be clinched over rings on each end. Sometimes an end chock, dapped into the beams, is fitted as shown by the dotted outline at "B," but this is rather unusual in steamers.

Chocks between the beams must be placed under all deck fittings which require through fastening. They are generally dapped into the beams from below as shown in Fig. 130 and may be placed either before or after the decking is laid. If their proper locations can be determined in time it is more convenient to set them before the decking is laid.'

Beneath these chocks heavy coverboards should be fitted as shown in the figure. These give a better appearance to the job and at the same time provide a necessary tie between the beams and chocks. The fastening for the coverboard and chocks usually consists of standard boat spikes and they must be kept clear of the holding down bolts for the fittings, which are to be put through later.

Chocks between beams must also be placed at the ends of the ship where decking ends land between beams as shown in Figs. 139 and 140. These chocks are not generally dapped into the beams. They should, however, be well fastened with either small-headed drifts or boat spikes.

Light chocks are also fitted where vent pipes or similar fixtures pass through the deck. These are not generally fitted until after the vent pipes are in place which is, of course also some time after the decking has been laid. A very convenient way of cutting them is shown in Fig. 131. When cut in this manner it is possible to secure a neat fit to the pipe and no other finish is required. It will be seen that with a small coaming on top of the decking, and this chock below, both fitting the pipe, it is not necessary for the hole in the decking to be cut with great accuracy. As a matter of fact, since such pipes vary slightly in size throughout their lengths, and also have overlapping joints, it would be impossible to secure a neat fit in the decking proper and still make the hole large enough for the insertion of the pipe.