251 
Problems of Commercial Hydrofoils 
DEL CARIBE 
riefunn 
Fig. 15. The PT 50 hydrofoil boat 
Figure 16 shows the general arrangement. The passenger room is divided into two com- 
partments which are separated from each other by the engine room. The forward cabin con- 
tains a bar, and a little saloon is provided on the upper deck, aft of which there are baggage 
compartments. Two PT 50 vessels which have been delivered to Venezuela are fitted with 
air-conditioning installations. 
Figure 13 also shows the power curve Ne/2 of the PT 50 for comparison with the 
PT 20. It reveals that the power is somewhat higher, especially at increased speeds, which 
must be attributed to the twin shaft and twin rudder arrangement and to the not very favor- 
able location of the propeller chosen in order to give better protection. 
Technical Data for the two types are as follows: 
PTE20 Bie SO 
Length overall 68 feet 89 feet 
Displacement fully loaded 28 tons 60 tons 
Payload 6.8 tons 15.0 tons 
Number of passengers 75 140 
Max. power 1350 hp 2700 hp 
Max. speed 42 knots 40 knots 
Cruising speed 38 knots 36 knots 
Power at cruising speed 920 hp 1000 hp 
Range 300 naut mi 300 naut mi 
Power/ton 48.2 hp/ton 45 hp/ton 
Power at cruising/Payload 135 hp/ton 134 hp/ton 
Power at cruising/Passengers 12.3 hp/pass. 14.3 hp/pass. 
The Supramar company is working on the design of some larger and faster types of 
hydrofoil boats intended for use under heavier, open-sea conditions and over longer dis- 
tances. A 110 multiple-purpose type with a carrying capacity of at least 200 passengers 
will be provided alternatively for Diesel and gas turbine propulsion. With two Mercedes- 
Benz engines of 3000 hp each, a speed of 47 knots is expected, which will be 
