SIZE, TYPE, AND SPEED OF SHIPS IN THE FUTURE 
J. D. van Manen 
Netherlands Ship Model Basin 
INTRODUCTION 
Owners and builders of merchant ships generally view radical new ship designs with a 
certain amount of cautious reservation. These people frequently realize from past experi- 
ence the expenses which accompany the development and application of new ideas in the 
field of naval architecture. 
In serving naval interests, however, the situation is different. Military considerations 
and economic and psychological factors all play important roles. The seemingly uneconomi- 
cal increases in the speed and power of tankers, and the development of nuclear propelled 
submarines, hydrofoil boats, and hovercraft are all projects which have been strongly stimu- 
lated by naval interests. 
A speed increase of 18 to 20 knots is no longer being considered by the designers of 
high speed boats such as hovercraft. Indeed, speeds of 40, 60 and even 100 knots are now 
being discussed. Designers of these new and progressive ship types are being confronted 
with questions such as: How can we develop a 100-knot ship for operation on, beneath, or 
immediately above the surface of the water? or What is the maximum shaft power which we 
can install on one shaft? One might perhaps just as easily ask: What is the maximum 
length of a ship? The answer to this last question could, of course, be given as all the way 
from New York to Amsterdam, since optimum performance at sea has here been assured and 
guaranteed. 
In all seriousness, however, the author hopes to convey that it can be nothing short of 
refreshing for the shipbuilder who is firmly established in mercantile construction to take 
an active part in and even take the very necessary initiative in the field of naval 
development. 
If we but look carefully at the developments of the past 20 years, the following facts 
become unmistakably clear: 
* The design of ships, which has heretofore been primarily empirical in character, is 
clearly becoming more and more scientific and fundamental in nature. Increases in ship 
speeds and ship dimensions and the development of new and different types of propulsion 
systems have required ever more theoretical treatment. 
Prior to 1940, the maximum shaft power which could be installed per shaft in merchant 
ships was in the order of 10,000 metric horsepower. At the present moment 16,000 shaft 
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