Inspection during Construction.-All boats which form a part of the statutory equipment of a vessel, must be constructed under the supervision of a ship surveyor from the Marine Department of the Board of Trade.

The Admiralty have a special staff to undertake the oversight of all types of pulling and motor boats, building for the Naval Service. The Overseers devote their whole time to this particular work; they have a very detailed specification to follow, and know exactly what they want. The supervision and the construction therefore proceed along satisfactory lines.

The inspection must be carried out systematically, and the visits arranged to prevent any delay to the construction. This can only be done by the appointment of inspectors who have had some experience in the profession and are permitted to devote a reasonable amount of time for the necessary supervision.

There should be at least four separate visits for inspecting particular portions of the boat during construction, which are as follows:

1. When the frame is complete, i.e. the keel, stem, sternpost, aprons, deadwoods, and hog-piece, have been trimmed, secured, and ready for painting or varnishing. An identification number is then cut in the keel, which follows the boat throughout its life on board any vessel.

The quality of the material, particularly the crooks, together with the fastenings, can thus be examined before the planking is commenced or any paint applied.

2. Inspection of planking before timbering. To enable a good soaking coat of white-lead paint to be worked on the inside surface of the planking, and thus allow the material behind the timbers to be painted, it is necessary to inspect the planking immediately before the timbers are bent into position. Opportunity is taken to reject any defective planks, particular attention being paid to the efficiency of the soleing, the snapeing away at the hood-ends and the faying surface of the apron. Where doublings are required they should be fitted and fastened before timbering.

3. Inspection of internal fittings, final inspection of planking and fastenings before painting. It is necessary to carefully examine all securities at the rising, stringers, thwart knees, thwart ends, mast hasp, mast step, gangboard, lifting-hooks, etc., and watch for butted timbers at the hog-piece. Inspect the buoyancy air-cases, measure their capacity, and test them by immersing in a tank of water. Measure the length, breadth,

and depth of the boat; ascertain the capacity by Stirling's Rule if required.

4. Final inspection before delivery. It is necessary to open out the portable floors in lockers, stern and head-sheets, to ascertain that all shavings have been cleared out of the boat. Make sure that the lifting-hook securities are satisfactory. Inspect the various hull fittings. Ship the rudder and ascertain if there is ample clearance. Try the steering oar in the grommet. Make sure there is sufficient seating accommodation for the total number of persons allocated to the boat. Step the mast, spread the sails, watch the traveller to see if there is ample clearance. Try the sheet ropes for length. Secure the shrouds. Examine details of equipment. See that the approved items of equipment are secured to the boat with lanyards. Carefully inspect the plugs. Secure the water breakers with lashings. Look at the life-lines and try all crutches in place. Cut dimensions on the correct side of the stem, and stamp the date of final inspection and initials of the Surveyor.

A few salient features to remember—

Secure the interest and company of the foreman at every visit to the yard.

Be straight and definite in all your demands.

Mark defects on the boat, and give your requirements in writing before leaving the yard.

Don't keep anyone waiting.

Don't ventilate your knowledge. You are "summed up" after ten minutes' conversation with a practical boatbuilder. Be of some assistance, don't keep all the information stowed away in portfolios at the office.

The details associated with lifting-hooks, sails, equipment, etc., are dealt with in their own particular section.

SECTION B.-CONSTRUCTION OF CLASS IB OPEN

LIFEBOATS

THE midship section of a Class Iв open lifeboat is shown in Fig. 2.

The construction is identically the same as that of a lifeboat of Class IA, with the exception that external buoyancy is fitted in addition to the watertight air-cases, and with a slight reduction in capacity of the internal buoyancy.

The total volume of the watertight air-cases in the Class La lifeboat must be at least equal to one-tenth of the cubic capacity of the boat, and in the case of the Class IB lifeboat, the volume f internal buoyancy given by the air-cases must be at least equal 7 per cent. of the cubic capacity of the boat.

When a lifeboat of this class is constructed of metal, an addition should be made to the cubic capacity of the airtight compartments (internal buoyancy), so as to give it buoyancy equal to that of the wooden boat.

If the external buoyancy is made up from cork, its volume, for a wooden boat, should be not less than thirty-three thousandths of the cubic capacity of the boat; if of any material other than cork, its volume and distribution should be such that the buoyancy and stability of the boat are not less than the of a similar boat provided with external buoyancy of cork.

If the internal capacity of a Class IB lifeboat is 500 cub. ft. the capacity of the internal buoyancy tanks will be

71% of 500 7.5 x 537.5 cub. ft.

=

and the volume of cork external buoyancy

500 X

33 1000

16.5 cub. ft.

This gives a total volume of 54 cub. ft., being an addition of 4 cub. ft. to the 50 cub. ft. of watertight air-cases required for a Class IA lifeboat of the same dimensions.

Fig. 113 shows in detail how this outside buoyancy is made up and secured to the structure of the boat.

The same principle of construction is applicable to the Class IIA open lifeboats.

The use of rushes, cork shavings, loose granulated cork, or any other loose granulated substance, and the use of apparatus dependent upon inflation by air, are not permitted for the purpose of external buoyancy.

The quality of the cork must be of the very best and obtained in long continuous slabs, well pinned together and to a wooden backboard not less than in. in thickness.

Its form in section should be such that it will not be liable to be torn away by contact with the ship's side when the boat is being lowered, and its shape maintained by means of wood sectional diaphragms secured to the backboard.

The operation of pinning and securing the cork must be

efficiently done, otherwise the external buoyancy becomes of very little use after the boat is in service.

Fio. 113.-Method of fitting outside buoyancy to lifeboats of Classes IB and IIA.

The cork, backboard, etc., are then covered with a good quality waterproof canvas and well painted.

The cork sections are made in three lengths, on each side of the boat, and secured to the planking in such a position that its lower

edge amidships is a few inches above the load water-line of the boat. They are made portable by fitting upper and lower strips of wood to act as a bearing for securing thereto the external buoyancy. These battens are about 21′′ × 11′′ and secured to the timbers by clenched fastenings; they usually take the run of the plank landings.

Galvanised iron straps about 3" x 3", with strong hinges at the top and bottom, and spaced not more than 2 ft. 6 in., are arranged to support the several lengths of cork combination. In way of the butts the breadth of the straps is slightly increased to provide sufficient bearing for the two ends. The edges of the iron straps are well rounded to prevent damage to the canvas and cork.

The upper and lower battens provide an air space between the planking and the external buoyancy. The hinges attached to the straps are secured to the battens by three screws, care being exercised that they do not pierce the planking. The pins in the hinges should be made of metal.

The two end lengths are slightly tapered; and to prevent damage to the cork when bringing the boat alongside a jetty or accommodation ladder, wooden sliver pieces are secured to the planking, as shown in Fig. 132.

The usual procedure is for the boatbuilder to fit the battens and secure them in position, make the backboard to suit, prepare the diaphragm sections and secure them to the backboard. Wood sections are forwarded to the smith to enable him to prepare the iron straps and hinges. The backboard, etc., is then given to the sailmaker or a maker of life-jackets, who prepares the cork slabs, secures them to the backboard, and covers the whole with the approved type of canvas.

The quality of the cork, etc., should be inspected before it is covered with the canvas.

In cases where the stability of boats has been found to be deficient, and in order to increase the moment of inertia of the water plane, the fitting of cork outside buoyancy has often been resorted to.

It is important to remember in arranging the overhang of the davits that account must be taken of the additional breadth given by the outside buoyancy attached to a Class IB lifeboat. The recognised breadth of the boat is the greatest breadth to outside of planking, and not to the outside of external buoyancy. The diameter of davits carrying this type of boat is, therefore, larger than a davit under which is stowed a lifeboat of Class IA,