This document contains information for predicting sea spray icing, including an icing prediction calculator and table matching icing classes and rates. The icing prediction results show moderate icing class and a rate of 0.7-2.0 cm/hr given inputs of 15 m/s wind speed, -5°C air temperature, and 1°C seawater temperature. Notes provide context that icing is unlikely above 7°C seawater temperature and explain adjustments for different water types.

1. 15,0 [m/s] = input
-5,0 [°C] = results
1,0 [°C]
salt T f = freezing point of seawater in °C (**)
26,1 [m°C/s]
Icing class moderate
Icing rate 0,7-2,0 [cm/hr]
PPR < 0 0-22,4 > 22,4-53,3 > 53,3-83,0 > 83,0 [m°C/s]
Icing class None Light Moderate Heavy Exteme
Icing rate 0 < 0,7 0,7-2,0 2,0-4,0 > 4,0 [cm/hr]
Notes:
(*): Overland, J.E., 1990: Prediction of vessel icing for near freezing temperatures
PREDICTION OF SEA SPRAY ICING (*)
V a (T f - T a )
1 + 0,3(T w - T f )
PPR =
Table: Icing class and rate
windspeed V a in m/s =
air temperature T a (°C) =
seawater temparature T w (°C) =
type seawater =
Icing predictor PPR =
These icing rates are only given as a guide. The actual icing rate will depend on the vessel's characerteristics,
heading, speed, exposure to sea spray etc..
Generally, icing is not a problem at sea temperatures greater then 7°C.
The above calculator and tables are based on a freezing seawater temperature T f of -1,8°C. If one wants to
use the calcuator for fresh or brakish water (d = 1,010) then choose one of the options in the drop down menu
"type seawater" ( (**) brakish = density abt 1,010, T f = abt 0,5 °C).
Icing prediction
prepared by: Capt. J. Buysse
buysse@seatec-consult.be