Mention has already been made of the order in which the keelsons and frames are placed in the ship, and of the fact that the ship's frame is in reality not completed until the main keelsons are down. From this point of progress the usual order of procedure would be about as follows: First, the dubbers are started to work on the inside of the frame. Ordinarily this work may be started as soon as enough of the square frames are up to permit ribbanding. In any event the dubbing should be kept well in advance of the ceiling gangs.

Following up the dubbing, the first timbers to be placed, after the frame is completed are generally the sister keelsons. Then the heavy ceiling is started, the lowermost strake at the lower turn of the bilge being the first put down. Where the ceiling is not edge bolted two gangs may be worked, and the ceiling would be started off in two places, first at the lowermost heavy bilge strake as above, and again at some point between decks, both gangs working from starting point upwards.

Where the ceiling is edge bolted, and it is the general rule to use edge bolts, then the operation of ceiling must begin with the lowermost strake that is edge bolted, which is generally the lowest heavy bilge strake, and continue in order thence to the uppermost clamp, the edge bolts being driven in each strake as it is run in. Deck beams below the upper deck must be placed as soon as the ceiling gang reaches the deck line. Likewise as soon as the deck beams are in, any waterways occurring on that deck must be run in before the ceiling can be carried upward. The running in of the waterways usually calls for the fitting of the shelves, in fact it is usually wise to fit both of these items at the same time as the fastening then can be driven to better advantage. Before the shelves and waterways are fitted however, the deck beams must first have been sprung to the proper, camber. Beams below the upper deck are not usually cambered. If there are no shelves, and hanging knees are to be fitted they may be placed as soon as the beams have been pumped up to their camber. During this time the hold stanchions may also be fitted and ironed up.

There is no set time for the placing of the thin bottom ceiling and it may be run in any time after the lower heavy bilge strake has been placed. It is often the last ceiling to be placed. However it should all be in place before any of the planking is started.

Note. - Although waterways are mentioned in this chapter it is considered that they more properly belong under the heading of deck details and they will therefore not be fully described until the next chapter.

It is most convenient to construct the lower hold bulkheads before the decking is laid, although bulkheads between decks are not generally built until after the deck upon which they rest has been laid. The arrangement shown in the detail plans will indicate the best order of procedure.

Pointers, if fitted to the ship, should be placed immediately after the ceiling, deck beams, and shelves are up.

The number and arrangement of keelson strakes appears to be within certain limits purely a matter of individual taste with the designer. There is apparently but a vague relation between the size of the ship and either the number or sizes of the keelsons employed. The number of individual arrangements used is much too large to even attempt to describe within the scope of these chapters. The types shown in Figs. 82 to 85 inclusive are types that have been used quite recently and therefore may be said to be of interest as indicating present-day ideas. The size of the ship, as well as the sizes of each of the keelson strakes employed in each type, are set down, so that the reader may be better able to follow the slight relation which does exist between the different types and the sizes of the vessels in which they have been used.

Type No. I, Fig. 82, it will be noted, consists of a main keelson with two strakes of rider keelsons above it, and one sister keelson on each side. Type II, Fig. 83, consists of a main keelson with five strakes of sister keelsons on each side of it. Type No. III, Fig. 84, consists of a main keelson with one rider, and a sister keelson on each side, each sister keelson having one rider making a six-strake keelson set. Included in this system are the girder keelsons, some distance out each side of the centerline keelsons. Each girder keelson consists of a lower strake locked over the floors and two lighter riders.

Inasmuch as the keelsons in this figure are used in large vessels as are also the ones shown in the figure following, which are very much lighter, it has been deemed best to show at this point, the keel, and planking arrangement next to it, for each of the types so that a more comprehensive idea of the actual relative centerline strength may be had. As a matter of interest, note that the limbers in Fig. 84 are cut along the center of the second garboard strake, and not in the frames. This arrangement, up to the time of its use in these vessels, was not a common one except in yachts and smaller vessels. However it is a good one, wherever it can be used, as it avoids cutting and weakening the floor at this point. Obviously this style of limber could not be used in Fig. 85.

Figure 83. Keelson Arrangements.

Figure 84. Keelson And Garboard Arrangement.

In Type IV, Fig. 85, it will be noted that there are but three strakes of keelsons. The outside planking is laid over two courses of thinner diagonal planking. These courses of diagonal planking cover the entire frame of the vessel. The lower ends, it will be seen in the figure, butt against the keel, the chocks marked "B" being fitted in the frame bays to receive the end fastening at those points.

In Fig. 84 there is no diagonal planking. In its place there is what is known as diagonal strapping, that is iron straps extending from the upper deck line down around the bilge to the floor heads, all arranged in both directions diagonally. This will be more fully described in the following chapters.

Essentially the arrangement shown in Fig. 84 belongs to the heavy scantling class of vessel, while that shown in Fig. 85 belongs to the light scantling class. This accounts for the principal differences in the two arrangements although some allowance may have possibly been made for the fact that diagonal planking is by many authorities considered more efficient than the strapping.

The fastening plans for each of these styles of keelsons are shown at the bottom of the plates and are self-explanatory. In both figures all clinched bolts driven in the main keelson, or its rider, are put through the keel and headed up over rings below. In Fig. 84 the sister keelson clinched bolts pass through the floors only while in Fig. 85 they pass through the first garboard and are headed up over rings below. In both systems the sister keelsons are edge bolted, it being generally customary to drive the bolts through and clinch them. Their number and arrangement may vary somewhat in different vessels, as also may the other fastening. In all cases detail plans are furnished, showing the exact arrangement of the fastening, and should be carefully followed.

Figure 85. Keelson And Garboard Arrangements.