xii CONTENTS. 



CHAPTER X. 



FISHERY HARBOURS. 



PAGE 



Difficulty of designing small harbours Injury inflicted upon boats by 

 " range " Inner basins and spending-beaches " Booms " Entrances 

 Risks incurred in entering tidal or barred harbours Fish deteriorate by 

 delayed delivery Berthage Quay space Water areaLoss incurred for 

 want of proper harbour accommodation Dimensions and equipment of 

 herring fishing-boats 1G5 



CHAPTER XL 



VARIOUS TYPES OF BREAKWATERS. 



Classification of breakwaters Vertical types Moundjy_pes Action of waves 

 against vertical faces Timber-framed breakwaters Breakwaters with 

 side walls of masonry andT hearting of loose^rubble Kilrush pier Wick 

 breakwater Danger of loose rubble hearting Advantages of using largo 

 blocks in constructing breakwaters Breakwaters formed of concrete 

 blocks laid in horizontal courses Defects of system Batter undesirable 

 Stone_focing Breakwaters formed of blocks resting on base of mass- 

 concrete Monolithic system of construction Methods of depositing con- 

 crete under water Causes of failure Concrete bag-work Fraserburgh 

 breakwater Wave-breaker Breakwaters of blocks laid in sloping courses 

 Advantages of system Colombo, Mormugao, and Manora (Kurrachee) 

 breakwaters Large blocks used at Reunion Mound breakwaters-- 

 Angles of slopes indicative of extent of exposure Plymouth, Kingstown, 

 Table Bay, and Portland breakwaters Pitched slopes Disturbance of 

 rubble by wave-action Holyhead breakwater Madras breakwater 

 Sorting rubble for breakwater mounds Cause of trouble at Plymouth 

 breakwater Alderney breakwater Causes of failure Mounds of pell- 

 mell blocks on rubble bases Mounds of rubble, faced and capped with 

 pell-mell blocks Mounds of pell-mell blocks, backed with rubble 

 Mounds of pell-mell blocks with superstructures Rubble mound with 

 pell-mell block facing and superstructure Economy and advantages of 

 using large blocks General observations on rubble and concrete block 

 nipunds Failures of pell-mell block breakwaters Particulars relating 

 to various pell-mell block LreaTswaters Rubble mound breakwaters, 

 faced and capped with stepped blocks in courses Particulars of cost, rate 

 of progress, maintenance, etc., of various existing breakwaters . , . 172 



CHAPTER XII. 



PIER-HEADS. 



Necessity for strengthening the ends of piers Range along harbour side of 



piers Various types of pier-heads Pier-head lights and fittings . . 222 



CHAPTER XIII. 



WAVE-SCREENS AND FLOATING BREAKWATERS. 



Designs for wave-screens and floating breakwaters based upon wrong hypo- 

 thesesDescription of wave-screens proposed by Hays, Scott, and Calver 

 Floating breakwaters Examples of, in nature Icebergs Weed-fields 

 Size of effective floating breakwater Behaviour of vessels riding at 

 anchor Impossibility of mooring floating breakwaters Inefficiency of 

 floating breakwaters Booms at harbour mouths Floating- weed type of 

 breakwater The mooring of lightships 225 



