SEA STATE — EFFECTS AND PROBLEMS 
by LEE M. HUNT, Technical Assistant 
Committee on Undersea Warfare 
National Academy of Sciences 
Washington, D.C. 
ABSTRACT 
Sea state exerts a greater overall effect 
on the Navy and merchant marines than any 
other single environmental factor, This paper, 
in order to emphasize this point, discusses the 
effect of wave height on background noise and 
surface reverberation which imposes limita-~ 
tions on sonar and radar effectiveness, and 
its effect on ship speed and ship damage, Wave 
forecasting, wave height observations, and the 
sea state code are also discussed from the 
standpoint of present practice and needed im- 
provements, 
INTRODUCTION 
Since man first went down to the sea in 
ships, or canoes for that matter, his worst 
enemy has been heavy seas, What astronom- 
ical value figure could we attach to the vessels 
lost and damaged by this age old enemy -- how 
many thousands of lives have been lost to its 
whim? We will never know, but some insight 
is gained by considering the fact that during 
the latter phases of World War II this enemy 
did more damage to our Pacific Fleet than did 
the Japanese, In one encounter off the 
Philippines in December 1944, 3 destroyers 
(HULL, SPENCE, MONAGHAN), 200 aircraft, 
and 790 men were lost. Twenty-eight ships 
were damaged, and 9 so badly that they re- 
quired major overhauls, Admiral Nemitz 
called this, ''The greatest loss that we have 
taken in the Pacific without compensatory re- 
turn since the First Battle of Savo."' 
The ''battle of the interface", however, 
has not been entirely one-sided. Man has 
made some progress beginning with Maury's 
sailing charts which, among other things, re- 
duced the average sailing time between London 
and San Francisco by 47 days. Sverdrup and 
Munk developed the wave and surf forecasting 
technique by which countless lives were saved 
during the amphibious landings of World War 
II. More recently, Pierson, Neumann, and 
James formulated the Wave Spectrum Method 
of wave forecasting used in the Navy's Ship 
Routing Program through which the average 
sailing time for Atlantic crossings has been 
reduced by 1 day and that of the Pacific by 5 
days. In addition, it has resulted in a drastic 
reduction in ship and cargo damage due to 
heavy seas. Backing up wave forecasting has 
been the indispensable progress in meteorology 
which provides the basic imputs to the wave 
forecasting machinery, 
The interface battle, however, is no 
longer concerned only with the loss of ships 
and lives in the direct sense, The battle be- 
came multifronted with the introduction of the 
submarine as an efficient and highly effective 
weapon during World War I. Its performance 
in sinking nearly 5 percent of the total British 
shipping during a single month (April 1917), and 
accounting for 69 percent of the 21, 000, 000 
gross tons of Allied peed ae lost to enemy 
action during World War II ° has clearly made 
it a weapon to be countered, But countering 
must be preceded by detection, and for this we 
"Superior numbers refer to similarly numbered references at the end of this paper." 
