Unusual Two-Propeller Arrangements 



The two systems should be of particular interest for large tankers and bulk- 

 carriers, which usually have a high and very irregular wake, and where the di- 

 ameter of the propeller often is kept small on account of the relatively high 

 number of revolutions of diesel marine engines for large ships. The two pro- 

 pulsion systems were therefore tested on a model of a tanker in the fully loaded 

 condition and in a ballasted condition. The model fitted with interlocking pro- 

 pellers is shown in Fig. 1, with auxiliary propeller in Fig. 2, and with ordinary 

 twin screws in Fig. 3. The principal data of model and ship fully loadi-d and 

 ballasted are stated in Table 1. 



Fig. 1 - Interlocking propeller arrangement 



Fig. 2 - Auxiliary propeller arrangement 



The interlocking propeller arrangement was tested with three different 

 distances between the propeller axes and with the propellers turning both in- 

 wards and outwards. 



1523 



