an 
TABLE I 
DISTANCES BETWEEN SOUNDINGS AND RANGES FOR ALL SURVEYS 
Max. Dist. Ave. Dist. Min. Dist. 
Type of Survey Between Between Be tween 
and Ranges and Ranges and Ranges and 
Method Used Soundings __—C Soundings Soundings 
Ranges Sdgs. Ranges sdgs. Ranges  Sdgs. 
Contract 
(Contact) 150 55 100 17 50 5 
Contract 
(Echo Sounder) 1000 100 375 36 100 15 
Gen ° Cove 
(Contact) 200 30 120 ays 25 25 
Gen. Cov. 
(Echo Sounder) 1000 100 400 38 5 20 
A number of suggestions were made by the Districts as 
possible means of improving shallow water survey methods. The 
one most desired is a faster and more reliable method of position- 
ing the boat and locating soundings. The other principal 
suggestions are as follows: 
a. Use the echo sounder method instead of the contact 
method wherever practicable. 
b. Develop an improved type fathometer. 
c. Use some electronic device such as radar for 
location of a "fix." 
d. Limit weight of equipment to one man loads if 
possible. 
e. Use of close range radar equipment in survey 
work. 
Further study of the data is in progress. 
