Van Oortmerssen 



Due to the non-linear characteristic of the bowhawser, the significant 

 force is not proportional to V y3 and f w yj , and therefore only results 

 of tests with tankers of comparable size in comparable sea- states 

 were selected. 



From Figure 2 1 it appears, that the results obtained with the 

 tanker moored to a fixed point represent approximately the lower 

 limit of the results of conventional single point mooring systems. 

 The forces occurring in the mooring line when the tanker is moored 

 behind the cylindrical storage tank, are much lower than those for 

 all other considered systems. 



These model tests have shown that it is advantageous to moor 

 a ship immediately behind a large fixed structure, though it should 

 be admitted that a rather simple case was considered, since the 

 additional effect of current or wind from a direction different from 

 the wave direction was not investigated. 



V. CONCLUSIONS 



1 - The wave loads on large structures due to non-breaking 

 waves can be predicted fairly accurately by means of a three-dimen- 

 sional source theory. 



2 - For the study of the anchoring of large structures or the 

 mooring of ships to large structures, an entirely theoretical approach 

 is not feasible and consequently model experiments are required. 



3 - Very large floating structures anchored in exposed areas 

 should preferably be either slender or semi-submersible; large 

 structures with a small length to breadth ratio will require extreme- 

 ly heavy anchoring equipment. 



4 - Mooring a ship on the lee -side of a fixed structure can be 

 of advantage. If the ship is moored to the structure by a single bow- 

 hawser, the force in the latter will be smaller than the force which 

 would occur in a conventional single point mooring system. 



972 



