XIII Congress of the 
International Society for Photogrammetry 
Helsinki, 1976 
Commission V 
Invited Paper 
IAN NEWTON 
University of Newcastle upon Tyne 
Newcastle upon Tyne, England 
Close-Range Photogrammetry as 
an Aid to Measurement of 
Marine Structures 
Photogrammetry was found to offer an accurate and rapid 
means for making measurements of ships and offshore 
platforms during construction. 
INTRODUCTION 
I INDUSTRY a growing demand has been 
created for the accurate measurement of 
components and assemblies as new manufac- 
turing methods, often based on numerically 
controlled machines, replace those which 
rely on human skill and judgement. In the 
past, where components had to be joined, 
holes and machined surfaces were carefully 
transferred from one part to the next and 
complex surfaces were checked out by using 
some form of prepared template. Nowadays 
the more efficient manufacturing methods 
result in higher productivity of components, 
in a variety of shapes and sizes, but quality 
control checks become vital to the effective 
functioning of an assembly system. 
As a technique for quality control, photo- 
grammetry has much to offer industry. It pro- 
vides a non-contact measuring process which 
is capable both of recording and of measuring 
a condition quickly, if necessary. This paper 
describes work undertaken to assess the 
value of photogrammetry in checking com- 
ponents and assembly of two marine struc- 
tures: fixed-base offshore platforms and 
ships. 
THE NATURE OF MARINE STRUCTURES 
Marine structures have the following 
characteristics: 
PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING, 
Vol. 41, No. 12, December 1975, pp. 1501-1512 
(1) They are assembled from a vast number of 
components. 
(2) They are large when complete—up to 
400m in length. 
(3) They are relatively inaccessible and it is 
impossible or impractical to reach all 
points on them following their assembly. 
(4) They are heavy and may contain up to 
30,000 tons of steel. This, combined with 
their size, makes movement and manoeuv- 
rability a demanding operation. 
(5) They are elastic and deform in accordance 
with their orientation, method of support, 
and wind forces. 
(6) They are affected dimensionally by 
changes in temperature. 
Generally the accuracy of any quality control 
measurements taken on component units 
must be better than + 3 mm. Those taken on 
the structure as a whole should be accurate to 
+ 10mm. 
Fixep-BASE OFFSHORE PLATFORMS 
In June 1975, some five years after the dis- 
covery of oil in British offshore waters, the 
first trickle of oil has come ashore to Britain 
from the Argyll Field. This trickle will gradu- 
ally build up to a flood as other fields come 
on-stream and Britain could become self- 
sufficient in oil by 1982. 
The development of the North Sea oilfields: 
has created an unprecedented demand in 
Europe for fixed-base offshore platforms. 
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