91热爆

Redcar beach in the fog.

4pm Sunday 05 April 2009

The mixed bag of weather continued, with everything from sunshine to thick fog coming our way over the past 7 days. The fog dropped down overnight, making visibility very poor first thing in the morning.

That created very difficult conditions for the full-time and part-time fishermen who launch their boats from Redcar.

Not many of the fleet have radar fitted to their coble, so making safe passage into and out of the harbour at Redcar needs careful use of the compass. A bearing of 063 degrees from the lifeboat slipway should take a boat straight to the Saltscar Buoy, clear of the treacherous 'scars' which lie in wait off Redcar.

Radar is a relatively new addition to the RNLI's fleet of lifeboats. It was in the 1960's that the first new lifeboats were built with radar equipment installed, while all the existing craft went without until the 1970's. Then, as the equipment reduced in size and increased in reliability, retro-fitting of simple radar devices began. This was not without it's challenges though.

All lifeboats are built to be self-righting. In the event of a capsize in heavy seas, the lifeboat will right itself within seconds. This is usually achieved by having inherent buoyancy built in to the superstructure. Some of the lifeboats of the 1960's and 70's, though, used a complex system of water ballast tanks which shifted seawater from one side of the lifeboat's hull to the other, causing it to flip the right way up.

This meant that adding extra weight to a lifeboat in the shape of a tall radar scanner had to be carefully designed and engineered so and to maintain the self-righting capability of the craft.

Once these issues were overcome, radar proved to be a vital tool in search and rescue operations in fog. Nowadays, the technology is even more advanced and a modern lifeboat carries a VDU display which overlays a radar picture of it's surroundings on a detailed image of the navigation chart of the area, telling the crew where it, and more importantly where a vessel in trouble, is.

It looks like the weather is taking a turn for the worse again next week.

Low pressure systems will swirl anticlockwise over us, bringing wind and rain all week up to the start of the Easter holiday period - traditionally the start of the busy season for RNLI lifeboats right round the coast of the UK and Ireland.

• Next