B L O 



607 



B L O 



Block, blocks ; and lift and top-sail sheets blocks, strapped 

 v together. 



To the boicsprit. The bee block, bolted to the 

 bowsprit at the outer end under the bees ; fore bow- 

 line blocks, lashed on each side the fore stay collar ; 

 fore top-sail bowline block lashed to an eye bolt in 

 the bowsprit cap. 



Fish block, is hung in a notch at the end of the 

 davit, and serves to haul up the flukes of the anchor 

 to the ship's bow. 



Girt-line blocks, in rigging the fore mast and 

 main and mizen masts, are lashed round the mast- 

 head, above the top of the cap ; one to hang on each 

 side. The girt lines that reeve through them, lead 

 down upon deck for hoisting the rigging, tops, and 

 cross-tree, and the persons employed to place the 

 rigging over the mast head. 



Cat block, is employed to draw the anchor up at 

 the cat head. (j. f.) 



Block. 



BLOCK MACHINERY. 



Block Ma- I HE immense number of blocks employed in the 

 chin ery. nay y t an J the great importance of having them accu- 

 " rately and substantially made, in order to insure their 



ready performance in every unfavourable situation 

 which the tackling of a ship is exposed to in bad 

 weather, render the manufacture of these articles of 

 far more importance than the generality of our read- 

 ers would imagine, from the appearance of so simple 

 an implement. Cases constantly occur at sea, in tem- 

 pestuous weather, where the failure of a single block 

 may put the vessel in imminent danger, by prevent- 

 ing the setting of her sails, or other important ope- 

 rations. At all times, the saving of labour on board a 

 ship will be very great, from having the numerous 

 blocks of her rigging well made ; for it is well known 

 to mechanics, that, in any system of pullies, a consi- 

 derable portion of the purchase they would otherwise 

 exert, is lost in the friction of the sheaves upon their 

 pins, and against the inside of the shell of the block, 

 as well as in overcoming the rigidity of the ropes ; 

 for these, if tight laid, that is hard twisted, will not 

 readily bend over small sheaves, but will take a con- 

 siderable power to force them into the sudden curva- 

 ture. Hence it follows, that blocks, with small pins 

 made of iron, the sheaves large, and coated or bushed 

 with metal, and all points of contact of the sheaves 

 and shell made accurately, and using slack made ropes, 

 will be the best means of diminishing the friction, 

 and, at the same time, rendering the apparatus durable, 

 a circumstance of equal importance to the seaman. 



These, and other circumstances, induced govern- 

 ment in 1802, on the recommendation of General 

 Bentham, to attend to the suggestion of Mr Mark 

 Isambard Brunei, a gentleman who had at that time 

 invented and taken out a patent for a complete set of 

 machines for the manufacture of every part of ship 

 blocks. He consequently employed Mr Maudslay 

 of London to erect from his designs an extensive 

 suite of machinery in the arsenal at Portsmouth, for 

 the fabrication of these articles. 



These machines were set to work in 1801, and 

 have been in constant use ever since. They consist 

 of 44 machines, forming in the whole the most com- 

 plete and perfect system of manufacture by machine- 

 ry, of any establishment which is to be met with in 

 this kingdom, or perhaps in the whole world, at least 

 of an article which has so many different parts to be 

 formed in hard materials, and has such a great variety 

 of sorts and sizes to be made by the same machines, 



not less than 200 kinds of blocks being manufactured Block Ma- 

 at these works. The mechanical contrivance, as well chinery. 

 as the elegant construction of the block machines, is 



at least equal, if not superior, to any examples of prac- 

 tical machinery, which we have at present contempla- 

 ted for the succeeding volumes of our work. Under 

 these circumstances, we do not think our readers will 

 require from us any apology for extending this ar- 

 ticle beyond the bounds which the manufacture of a 

 ship's block alone would deserve. To our mechani- 

 cal readers, this article, and its accompanying Plates, 

 will be highly acceptable, as presenting them with 

 a number of curious machines, which may in their 

 hands, at the expiration of the patent, be rendered 

 applicable to a great variety of other similar opera- 

 tions in the mechanical arts, which are now perform, 

 ed by manual labour. 



Before proceeding to the detailed description of 

 the drawings of the most striking of these machines, 

 we shall give a general outline of the operations 

 which a block and its sheave, or shiver, are subjected 

 to, that the connection of one machine with another 

 may be more clearly understood. The machines are 

 put in motion by a capital steam-engine of 32 horses' 

 power, erected by Messrs Boulton and Watt. The 

 whole establishment contains 44 machines, as before 

 stated, which form three sets, that is, three blocks 

 of different sizes may be proceeding in all their stages 

 at the same time, though in some of these stages one 

 machine operates at the same time upon two, or even 

 ten blocks. The building or block mill is of great 

 length, having the steam-engine in the centre, which 

 therefore divides the house into three lengths : the 

 centre, which is a large and tall house, for the engine f 

 and two wings for the mills. One of these wings is 

 devoted to the machinery for sawing and converting 

 the timber into scantling, that is parallelopipedons, of 

 the proper size to form the different blocks ; this de- 

 partment contains seven large sawing machines. On 

 the opposite side of the building are the machines 

 which form the blocks and their sheaves : These are 

 smiller and more delicate engines, being V>7 in num- 

 ber. It is to. these we shall chiefly turn our atten- 

 tion in this article, because they are the real block 

 machinery ; the other seven, though no less deserving 

 of notice from their ingenuity, and perhaps superior 

 from their general utility, are only Mwing-machineSy 

 and equally applicable to sawing wood for any other 

 purpose besides block making : We shall therefore 

 6 



