94 



BOATS, COLLAPSABLE. 



comes a boat, but baving as yet only one skin, 

 it would only float so long as that skin is not 

 pierced. But now let us suppose another skin 

 to be applied to tbe inner edges of these len- 

 ticular segments and made water-tight, not 

 merely is there a boat within a boat, but the 

 spaces between the segments, being all sepa- 

 rate and distinct, an injury to one does not 

 affect the rest." 



In fact the structure forms a true life-boat 

 amply provided with water-tight compart- 

 ments, and capable of anything that an ordi- 

 nary boat can do, except that its canvas skin is 

 more easily pierced than the wood or iron of 

 which boats are usually constructed. So long 

 as the Berthon boat is properly handled and 

 kept in open water, she is 

 as safe as any other boat of 

 her size. 



Fig. 1 is a sectional view 

 of a boat folded and open 

 as explained in the con- 

 text. Fig. 2 shows a fully 

 equipped boat at the davits 

 with the temporary canvas 

 covering partly removed to 

 show the profile of the 



lenticular segments heretofore described) which 

 are hinged to the stem and stern posts. When 

 collapsed these timbers fall down on either side 

 of the keelson in vertical and parallel planes, 

 and when opened they assume such positions 

 as to form the skeleton of the boat, extending 

 the two canvas skins as described. 



Experiments were at first made with India- 

 rubber, but while it served admirably when 

 new it was found that it would not stand 

 exposure to changes of climate, and this 

 failure led the British Admiralty to condemn 

 the boat as a failure. Years elapsed before 

 they could be induced to reconsider their 

 availability when covered with canvas. The 

 canvas as now prepared is saturated with 

 boiled oil and litharge, and 

 in every ten pounds is dis- 

 solved one pound of yellow 

 soap. This keeps the fab- 

 ric soft and pliable, and 

 at the same time increases 

 its strength. Boats thus con- 

 structed have been in use 

 for from four to eight years, 

 and are to all appearance as 

 serviceable as they ever were. 



FIG. 2. BERTHON FOLDING-BOAT. SHEER PLAN. 



folded boat. One very important feature of 

 these boats is that they open themselves au- 

 tomatically as soon as the weight comes on 

 the falls. There is therefore nothing to be 

 done but to swing the boat clear of the chain- 

 wale and lower away. Of course the same 

 difficulties in taking the water are present as 

 in the case of ordinary boats. 



The materials used in construction are mainly 

 wood and canvas. The longitudinal timbers 

 are preferably strips of American elm, steamed 

 and bent in a mold, and riveted together with 

 copper. The stem and stern posts are attached 

 to the keelson, and on each side are four longi- 

 tudinally curved timbers (A A A, Fig. 1) (the 



In practical service these boats collapse into 

 about one fifth of the space occupied by an 

 ordinary boat. They may be laid one on top 

 of another, stowed below decks, or, which is 

 by far the best plan, lashed along outside the 

 bulwarks as shown in Fig. 2. It is said that 

 the frames are strong enough to sustain the 

 full complement of passengers at the davits, 

 but lowering a crowded boat into the water is 

 extremely dangerous and, as with all boats, it 

 is best to allow the crew only on board. 



The Berthon boats are built of all sizes, 

 from the light, single-handed canoe, easily 

 folded and carried under the arm, to the large 

 life-boat, 40 feet long by 13 feet beam. Boats 



