Norrbin 



on the ship in motion parallel to a wall is essentially inversely pro- 

 portional to the separating distance, i.e. Y(u,t)J = i Y^^ 5 • u^tIj, 

 and that the effects of two walls may be approxinnated by super- 

 position. Thus for Y(u,T|g,T|p) 



iY..._u2Tl, + iY,,„,u^, = iY,,,uS (10.5) 



Ip ~ 2 -^UUTJ^ 



where Y^J^^y|- Yyy^g- Yyy^p, 



As the ship nnoves closer to one of the walls, or as the walls 

 are closer, this expression shall be completed by terms in rjg and 

 HpHp* or alternatively, in r]r[. 



The effect of_a limited bottona depth is included by additional 

 terms in T|t, and titi^. The forces due to steady sway and yaw are 

 assumed to be increased in proportion to uvt) and urT|, and to uvt)^ 

 and \irr\t, respectively. The dependence of^ added inertias on the^_ 

 confinements are represented by terms in v^ and vr|%,rt, and rT| ^ , 

 all so far evaluated from the results published by Fujino, [ 5] . 



XI. MODEL TESTS 



Test Program and Model 



Five years ago an experiment program was designed for a 

 tanker model with a view to put to test the analytical model set up 

 as well as to obtain basic simulator data for a first canal transit study. 

 Full scale measurements should subsequently be made with the 

 98 000 tdw prototype in the Suez Canal, but these plans could not be 

 fullfilled, of course. 



In Novenaber 1965 a first series of three component force 

 measurements were ordered to be run with a 1:70 scale model at the 

 VBD Laboratories in Duisburg. The test program included straight- 

 line oblique towing of the propelled model in "deep" and shallow water 

 in the large Shallow Water Tank and rotating arm tests at same depths 

 in the Manoeuvring Tank, It also included straight-line oblique towing 

 of the same propelled model in two Suez -Canal- type sections with a 

 water depth equal to that of the shallow water tests. Most of these 

 tests were run at self-propulsion point of model, determined from 

 straight course speed runs in the waterways studied. All tests were 

 performed at maximum "Suez draught. " Resistance and propulsion 

 tests had earlier been completed at SSPA with a 1:35 scale model on 

 several draughts, and ship speed trials were aneilyzed to support the 

 prediction of full scale screw loadings and control derivatives on 

 model test draught. (Cf. Section VII.) 



880 



