Seacocks Specialists Explain How to Get Through Those Low Pressure Situations

Your Seacocks Professionals Make Those Difficult Sailing Conditions Look Much Easier With These Tips 

Raritan Engineering Company your seacocks analysts would like to share with you these topics we thought would be of interest to you this month regarding how to get through those low pressure situations.

Your seacocks experts know that in conditions which are typical of the leading edge of a fast moving South Atlantic low, it is the ability to regulate speed and the level of attack which is being tested for the skippers at the top of the Vendee Globe fleet this morning.

Winds are reported to be from just east of north at 25kts, with relatively flat water. The speedo on board Alex Thomson's race leading Hugo Boss has been hovering around 24-25kts for a 30 minute period and the British skipper is 112 miles ahead of second placed Armel Le Cléac'h on the early morning ranking.

On seas, which are still relatively calm, the monohulls have ideal conditions to threaten the 24-hour record set by François Gabart in 2012 (534.48 miles). They need to achieve an average speed of 23 knots to sail 550 miles in one day and the skipper of Hugo Boss has been at those speeds since early last night and looks set to maintain that pace for the next couple of days…

Heading towards Tristan da Cunha

This foiling folly should indeed last two or three days as they ride on the back of the low sliding down very rapidly towards the Roaring Forties. 

It is therefore practically certain that Yann Éliès (Quéguiner-Leucémie Espoir) will be left waiting almost 600 miles back at the station for the next train off Cape Frio. 

I stood there, facing the seated crowd of sailors and asked,  “How many of you have a basic minimum or less understanding of how to read a weather map?” At least 70% of the group raised their hands. 

Visit http://raritaneng.com/product-category/trudesign/seacocks/ to find more information as well as get assistance on seacocks at Raritan Engineering.

“What could it possibly have to do with me or my sailing?” they may have asked themselves at earlier points in their sailing lives. But here they were, committing a day to learn how to decipher the lines and make sense of the squiggles in order to make informed decisions going forward. 

That still doesn't explain all of those seemingly random swirling lines that surround the highs and the lows. On a surface pressure map, those lines are “isobars”-iso referring to “same” or “equal” and bar referring to barometric pressure. Those lines will tell us how quickly the pressure changes over a horizontal distance. 

Isobars not only imply wind speeds, they also imply wind direction. You may be aware that wind circulates around a Northern Hemisphere high-pressure system in a clockwise direction. 

Wind doesn't travel concentrically along the isobars, though. The wind will tend to want to get away from the high-pressure area and be drawn in toward the low-pressure area. Hence, at the surface of the planet over water, wind around a high-pressure area will toe out from the isobars at about 15 to 20 degrees and toe in towards the low-pressure system by the same amount. 

Of course there are other lines on that weather map. Some of them, indicating frontal boundaries, have little icons located along their length. The ones with triangles represent cold fronts. The ones with semicircles represent warm fronts.

Cold air is denser than warm air. When it tries to move towards a warm air mass it's like a bus trying to move a stack of pillows out of the way. It can do it pretty quickly. So, when a cold front comes through an area, the temperature in that area can change pretty quickly. 

Occluded fronts result from cold fronts overrunning warm fronts and the air masses mixing with each other. As those air masses mix, there tends to be less temperature differential and less wind along an occluded front than even along a warm front.

Learn more at Raritan Engineering regarding seacocks and other marine products.

via Vendee Globe – Riding the area of low pressure

via The Dark Art of Weather Analysis