Weather working day (WWD). This is defined in the Charterparty Laytime Definitions 1980 as: “. . . a working day or part of a working day during which it is . . . possible to load/discharge the cargo without interference due to the weather.
If such interference occurs … there shall be excluded from the laytime a period calculated by reference to the ratio which the duration of the interference bears to the time which would have . . . been worked but for the interference.”
Weather working day. This expression means a working day or pan of a working day during which it is possible (if the vessel is loading or discharging) or would be possible (if the vessel is not loading or discharging) to load or discharge the cargo without interference due to the weather. If such interference occurs, or would have occurred if cargo operations had been in progress, there shall be excluded from the laytime a period calculated by reference to the ratio between the duration of the interference and the time, which would have or could have been worked if the interference had not occurred.
This explanation which is similar to that given in the “Charterparty Laytime Definitions 1980” seems to be complex. It can be uncertain to decide if cargo work would or would not have been prevented by bad weather. The uncertainty increases with the difficulty of proving whether or not cargo operations were intended (“ . . . if cargo operations had been in progress . . . “). To reduce the chance of disputes between charterers and owners on the effect of weather on laytime if cargo operations are not being carried out, the patties may use me decision of port authorities on periods which would have interfered with cargo operations. Some port authorities issue circulars declaring that certain days were not “weather working days” because of inclement weather conditions, for example, because a typhoon was passing or nearby.
The ratio of time lost to the working time is significant. For example, in a port it may be customary to work continuously over 24 hours. If rain prevents actual cargo operations for, say, six hours, only six hours is excluded from the laytime used. However, the working hours in the port may be from 00.00 hours to 07.00, 08.00 to 15.00 and 16.00 to 23.00, and rain occurred from 06.30 to 09.30 and again from 14.00 to 18.00. Even if the vessel was not engaged in cargo-handling operations, the time saved for the charterer would be calculated as follows:
Working time = 21 hours
Rain interference = 7 hours
“Lost” = 7/2.1 of a “working” day (or 1/3)
One “day” = 24 hours
Therefore, 1/3 of a day, or eight hours, would not be counted. This means that for that day only 16 hours of laytime are used.
If the laytime clause is further qualified by the addition of the words “of 24 consecutive hours” after “weather working days”, this may operate in favour of the shipowner. In the example given above, the seven hours lost by rain would not be counted; for that day 17 hours of laytime are used.
The period, which allows laytime not to be counted, does not depend on actual loading or discharging operations being carried out. From the owner’s side, it may be better to allow the charterer to exclude bad weather periods only if cargo handling was in progress. For example, a clause dealing with laytime could include:
“Should any time be lost while vessel is in a loading (or discharging) berth owing to work being impossible through rain, snow or storm, the amount of actual time so lost shall be added to the laytime.”
The effect of such a clause would be that the charterer could prove that there was a period in which work was impossible because of bad weather but he would also have to prove that that resulted in loss of time to him because he was ready to use the time. For example, the vessel could be in a loading berth and the cargo is available and alongside but the weather prevents loading. This would be similar to the original understanding of “weather permitting”.
After The Vorras, 1983, decision, “weather permitting” and “weather working days” (without any qualification) have the same effect on laytime.