The lining of the ceiling is a very simple operation though requiring some skill and experience to obtain a result pleasing to the eye.

The first line to be established in the lining operation is that of the upper deck. The points indicating the location of this line, it will be remembered are marked on the top timbers, or stanchions, when the frame is molded, but as the frame has gone through the process of assembling and erecting since these points were marked, they could hardly be expected to remain at exactly their proper height or in a fair line. Therefore fairing, or sheer, battens must be tacked up on each side of the ship, care being taken to so place the battens that they will be at the proper height above the top of the keel at all points. It will be found generally that the points previously marked on the frames will have to be disregarded, but they will still form a valuable guide for setting the battens. The proper heights for the battens should be entirely remeasured at a sufficient number of points to insure their proper location, after which they may be faired between these points by the eye. In general the old deck-fine points will be found below the true points, due to natural settling of the frame, and to the shifting down of the timbers when the butts are cut in on the framing stage.

In some yards the sheer battens are placed on the outside of the hull, but in most cases it will be found best to place them on the inside of the frames, as in this position the eye can follow them from end to end of the ship.

Once this line is established, the tweendecks line, or any deck line below the upper deck line, may be lined out by simply measuring down the proper distance from the upper deck line. These distances are always shown on the detail plans.

The line of the lower strake of the heavy bilge ceiling is determined by two conditions: First, the permissible amount of taper in the siding of the bilge strakes at the ends of the ship, and second, the position of the line should be such as to permit running all strakes without spiling, i. e., it should be possible to edge set all strakes into place.

The first condition is merely a matter of measurement down from the lowest deck line, the distances first measured being such as will allow a reasonable amount of taper on the hoods. This will approximately establish the line of the lower bilge strake. Then, to find out if the second condition is satisfied a thin batten is set along this line, the batten being allowed to "fly" at the forward and after ends of the ship. The amount it springs above the line will indicate the amount of edge set required to get the strake into place. An experienced liner's judgment will at once tell him if it is possible.

If, after this line is run in, the thick ceiling does not extend down far enough to cross the assistant keelson ends, then strakes of the thin ceiling are carried around on the ceiling line to close off this work. The balance of the thin ceiling is run straight fore and aft, the ends being nibbed into the adjoining strakes in much the same manner as will later be described for decking.

Once the deck lines have been established, and the lower line run in, the work of lining the ceiling then becomes merely a matter of fitting a given number of strakes in a given room. By spacing off the number of strakes, at frequent intervals into the total room to be occupied by them the width of each strake at each interval is obtained. Then all of the strakes for that particular room will be cut the same widths and tapers. This operation will be more fully described under "Planking".

The most important single operation in ceiling, with the possible exception of the lining, is the bevel taking. There are two general methods of beveling so that the edges will fit together. The first, shown in Fig. 94, can be used in any location. Here both, edges of each strake are beveled off, each bevel being about the same. The second method shown in Fig. 95 is where only one edge of the ceiling is beveled, the other edge being left square. It will be seen that where the bevels are heavy, as around the bilge the latter method leaves projecting corners inside. Therefore the second system should not be used where the bevels are very heavy.

The total equipment for bevel taking consists of a ship carpenter's, bevel, a bevel board, Fig. 96, and a degree board, Fig. 97. Only one edge of the bevel board need be straight.

With these tools at hand the bevel taking would proceed much as follows: First, the bevel would be held in the position shown in Fig. 94, the handle being held firmly against the edge of the strake in place, the blade being so set as to give the correct bevel for the next strake. This will require some practice as will be seen from the following explanation.

If the length of the bevel blade was exactly the same as the width of the strake for which the bevel was being taken then the correct bevel would be obtained by setting the blade hard against the frame. As a rule, however, the bevel blade is shorter than the width of the strake, so the blade should not be set hard against the frame but should be set in the position it would assume, if its length were the same as the width of the strake and it had been set hard against the frame. Thus it will be seen, that, where the bevel blade is short, it will set out from the frame at the upper end, when adjusted to the proper bevel. The amount of this "set out" must be determined by experience.