66 IMPROVED FISHERY HARBOUR ACCOMMODATION 



The diminishing of the power of the waves by their 

 breaking in a race outside may benefit a harbour, and 

 enable the engineer to construct his works at a less cost 

 in dimensions of materials, and in the extent of piers in 

 length and contents. 



Mr. Stevenson observes if a harbour work were placed in 

 a rapid tide the masonry would be exposed to the action 

 of a very trying and dangerous high-cresting sea, and he 

 gives as an example the harbour of Port Patrick in Wigton- 

 shire, where the violence of the waves is to a great extent 

 due to the rapidity of the tides ; if, on the other hand, the 

 race, or roost, runs in such a direction as to be entirely out- 

 side of the harbour and at some distance off, it will, while it 

 lasts, have a decided tendency to shelter the works, and to 

 act as a breakwater. 



THE TIDES ALWAYS INCREASE THE SURF ON THE 



SHORE. 



Mr. Stevenson says sometimes this is the case, but the 

 writer's experience is decidedly to the effect that the dis- 

 turbance in strong winds always increases with the speed 

 of the current and height of the water, and that, as Mr. S. 

 says, the most damage is done from one to two hours 

 before and after high water. It is easy to understand this, 

 for the incoming tide brings the swell with it, because the 

 various rocks outside, or banks, are gradually becoming more 

 covered, each of which is a small breakwater of itself, and 

 the whole combined have a very decided effect, when un- 

 covered, in smoothening the waves. Mr. S. particularly men- 

 tions in another place, that very much less sea breaks on the 

 Skerryvore Lighthouse as the offlying rocks become un- 

 covered. As regarding the effects at or near high water, he 

 mentions " that a large body of water was thrown on the 



