At 6 a.m. this morning the barometer displayed a drop in pressure which has unfortunately put a temporary halt to all scientific work. In anticipation of an approaching low pressure zone and the bad weather associated with it the CTD surveys were stopped last night in order to allow adequate time for deploying the northwest mooring which consists of sediment traps and current meters amongst various other pieces of equipment. In addition we also needed to use the swath bathymetry system in order to map the topography of the seabed at this site. Data acquired from the swath surveys is required to plan for the subsequent deployment of other equipment - for example the identification of suitable flat areas which can be sampling using the OTSB trawl, so it was important for us to complete as much work as possible before the bad weather hit.
Today’s weather has seen a between gale force 9 and 10 on the Beaufort scale. For those of you wondering the Beaufort scale was introduced in 1806 by Sir Francis Beaufort – an admiral of the British navy, who devised a system of measuring wind speed. The system is still in use today and consists of 12 stages, each one with an associated range of wind speeds in knots and water surface characteristics such as wave height. 0 on the Beaufort scale is classed as calm with wind speed of 0-1 knots (0 miles per hour) and characterized by a flat, mirrored surface, whereas 12 is classed as a hurricane with wind speeds of 64 knots (75 miles per hour) or higher and a wave height of 14m. Today we typically experienced an average wind speed of 40-50 knots and a wave height of 7m – not exactly a hurricane but more than enough to produce some impressive waves and a ban on setting foot on deck!
For the bulk of the scientific staff bad weather means a lot of free time which is generally taken up by reading, catching up on sleep, watching DVDs or having a few drinks in the bar- possibly even working up samples in the lab. What many of us don’t take into consideration is that the crew of the James Cook still have to keep the ship running (not to mention afloat!) in these conditions so I decided to find out how the crew and the ship itself cope with a rough spell.
During bad weather the wind and waves cause the ship to pitch up and down and roll. The side to side rolling is counteracted by the ship’s stability tank which uses displaced water to cushion the effects of the waves. The up and down pitching is controlled by sailing on the most comfortable heading into the oncoming waves at a minimal speed. The downside of this is that the ship is basically riding the bad weather out and may not maintain the correct heading, as we saw during a previous spell of bad weather when we ended up 50 miles off course.
From the crews standpoint a priority is placed on properly securing all equipment and supplies so that won’t come loose, which could lead to serious injury, damage to the ship or to the equipment itself – in short personal safety is the prime consideration. Generally work is undertaken only when absolutely necessary, this could include restarting the engine which may become blocked with water which is normally immiscible in the fuel but may temporarily mix due to the rolling of the ship. The galley staff still have to prepare meals- fried food is obviously not an option and I can’t imagine its all that easy to cook with your ingredients rolling around. All in all its a pretty incredible feat and not one I would like undertake as I certainly don’t possess the required balance let alone patience, so well done and thank you to all the crew of the James Cook!
NOC, Southampton, UK