2jo NOTES ON DOCKS AND DOCK CONSTRUCTION. 



Mr. Blendy remarks in his paper on dock gates, 1 that when 

 gates are of large size, the weight is greater than can be safely 

 allowed to depend on the attachments at the heel-post, unless 

 means .be adopted to reduce the working weight by the aid 

 of flotation or otherwise, and even then it is advisable to 

 provide against accidents from defective fastenings. 



Although abutments may be constructed of ample strength, 

 the constant vibration caused by heavy gates swinging back- 

 wards and forwards will have some detrimental effect on the 

 masonry, or the mass may give slightly one way or the other 

 without any apparent reason. Anchor-straps, however well 

 adjusted and keyed up, will soon wear slack, or the anchor-bolts 

 may deteriorate through rust. 



A reasonable conclusion appears to be that, with a moderate 

 width of entrance, say not exceeding 60 feet, 2 rollers may be 

 dispensed with entirely ; but that in the case of entrances 

 exceeding 60 feet, 8 while it is desirable to hang the gates 

 as much as possible from the anchor-blocks and heel-pivot, 

 rollers are necessary, attached in such a manner as to relieve 

 the wear and tear on the anchor fastenings and heel-pivot. 

 This applies with additional force when the gates are worked 

 at considerable variations of tide. 



Support to Dock Gates when exposed to Rough Water. 4 Mr. 

 Ramsey, the resident engineer at Ramsgate Harbour, devised 

 the following method of supporting the entrance gates under 

 the very severe strain to which they were subjected when 

 struck by waves when the tide outside was nearly level with 

 the water in the basin. 



The end of a stout beam or stay of greenheart timber was 

 connected, by means of a massive iron movable joint, to the 

 fore part of each gate near the mitre-post on the inner or basin 

 side, and at about high water of equinoctial spring tides. The 

 opposite end of this beam passed through an opening in the 

 masonry of the side walls of the entrance. The inner end 

 of the beam was supported by a small bogie truck running upon 

 a pair of rails laid in a channel underground, the object of 

 this being to support the inner end of the beam and admit of 

 its ready motion in a horizontal plane. 



On the vertical face of the beam nearest the gates was 



1 M.r.I.C.R, vol. Iviii. p. 155. 2 Ibid., vol. lix. p. 14. Ibid., p. 5. 



4 Ibid., vol. xxxi. 



