Jökull - 01.12.1969, Page 112

Fig. 2. Icing of a ship, handrails.
ot' data has now been collected. Walden (1967)
has summarized the effective icing factors from
sea water spray (Table 1).
The íirst item, meteorological and oceano-
graphic conditions, includes primary conditions
for the formation of icing. In order to produce
icing from sea spray, the spray has to collide
at least on parts of the ship, and sea and air
temperatures have to be such, that part of the
sea spray freezes on the ship. Icing will accu-
mulate in shorter period of tirne and will be
more severe, if sea spray is constant and the
temperature of sea and air low. However, if
the air temperature is below — 18° C, the
spray freezes in the air before touching the
ship, and therefore does not produce icing. It
TABLE 1
Factors which influence
1. Meteorological and oceanographic
conditions
2. The ship
3. Movement of the ship
4. Place of measurement on board
icing from sea water spray
air temperature
water temperature
wincl force
state of sea: height, steepness, number of wave
patterns, foam in the air, salinity
size
design
load (freeboard)
course relative to wind and sea
speed
height above water
position in relation to ship’s super-structure
and liull.
108 JÖKULL 19. ÁR