now used in Portsmouth Harbour. 193 



much exceed the expense of making and fixing a claw, which is 

 hable to injurv, by vessels grounding on, or hooking fast to it, 

 nor is its durabjlitv beyond iO or 50 years, even where it remains 

 undisturbed, whereas the cast-iron blocks will last for many cen- 

 turies. 



I am likewise informed that the blocks may be cast at tlie 

 foundry, in the yard, if your Honourable Board tJiould approve 

 of a furnace being erected for that purpose, which would mate- 

 rially lessen the expense. 



1 have hereunto annexed a description of the trials, a))d have 

 forwarded i)y this night's coach, two, drawings. 



No. 1, showing the present method of securing the ground 

 chain. 



No. 2, showi'.jg the manner in which the mooring block was 

 tried. 



And by Clark's waggon, a model of the block. 



I an?, sir, &c. 



J. Park. 



Descripiinn of the Trials made with the Cast Iron Monrivg 

 Block, invented hi me, and now humbly s?ibmitted Jor the 

 consideration of the Honourable Nary Board. 

 Fir=;t, The cast-iron mooring block, weighing 1'-I2 cwt. was 

 placed on the shore some distance from lov/ water mark, and an 

 anchor of 85 cwt. (exclusive of the stock, which weighed about 

 35 cwt.) was also placed the same distance from low water mark, 

 and (15 fathoms from each other, on ground of the same quality; 

 15 fathoms of mooring chain were attached to each, and to the 

 end of each chain four treble blocks of 22 inches; four three- 

 fold purchases of new G-inch hawser rove, and two mooring 

 lighters, with 40 men in each, grounded, one abreast of the cast- 

 iron block, and the other abreast of the anchor ; the falls were 

 brought to the capstans and windlasses and the strain applied to 

 heave the mooring block and anchor towards each other. 



Both drew ; the former oiie inch to one foot of the latter, until 

 the mooring block had drawn about the distance of its own base, 

 when having conijjletelv buried itself, it became stationary, but 

 the anchor continued to consc home (notwithstan<ling it was 

 buried to the upper flook) until every one present was satisfied 

 that any further trial with an anchor of that weight was use- 

 less. 



Second, being willing to make further trial, I causecl an an- 

 dior of 95 cwt. (namely, the Nelson's best bower) to be laid down 

 &» before, and the same jjurchase to be applied ; but the po\rcr 

 not being sufficient to move either the block or anchor, 10 ad- 

 ditional men were sent into each lighter, when the anclior started, 

 . Vol. 56. No. 261). Hept. Ib20. B b and 



