Have you noticed that some tall ships fly a black flag with a question mark on it, rather like a pirate flag? Here’s why.

Back in 2000, the Parliamentary Assembly of the Council of Europe (PACE) issued recommendation No 1468, which asked European Community governments to:

• Support and encourage private bodies which preserve historic vessels
• Encourage the display of these vessels for the general public
• Encourage further development of a system of mutual acceptability by the maritime authorities of nation states of standards for the safe operation of traditional vessels

In 2000,  most important European seafaring nations reached consensus on the basic rules for the operation of traditional vessels, and agreed to mutually recognise national provisions in this field. They issued a Memorandum of Understanding intended to ensure that traditional vessels and their crews could move freely in and out of European ports and national waters.

However, very little was done. For example, modern fire safety regulations for commercial ships forbid the use of wood below decks: any port that enforces this regulation will refuse access to almost every traditional ship.

In 2008, the Baltic Sail Conference, held in the ancient Hanseatic port of Rostock, issued the Rostock Declaration calling on all responsible persons to:

• Use their influence to solve the problem of the acceptance of national regulations for traditional ships (on international voyages)
• Use their influence to urge governments to work together to establish a European Maritime Policy for traditional ships.

Want to know a bit more? Take a look at the Black Flag flyer

The problem is that fire extinguishers send out a powerful jet. Although the video shows the fire extinguisher killing the fire instantly, it also shows chunks of the pan’s contents being blown all over the galley.

On 11 Feb 2009,  Inmarsat C helped to repel pirates who tried to attack a bulk carrier in the Indian Ocean.

The 53,500 DWT vessel was approximately 100 miles south east of Socotra Island when the attack happened.

Five pirates armed with rocket-propelled grenades and assault guns approached and attempted to board. They fired towards the accommodation section and the ship then alerted naval units in the vicinity via an Inmarsat C distress priority piracy alert.

The pirates broke off the attack because of the response from one of the naval units, and were also deterred by the sea swell and evasive manoeuvring carried out by the vessel.

How Do Inmarsat Piracy Alerts Work?

The International Maritime Bureau (IMB) receives piracy alerts from ships and then broadcasts detailed piracy alerts to all ships in the ocean region using the Inmarsat C SafetyNET system.

Inmarsat’s head of maritime safety services Brian Mullan said: “This shows how effective Inmarsat C can be in not only sending out distress priority alerts from ships but also as a highly effective means of receiving the latest information which will alert the ship’s master to incidents in his area.”

About SafetyNET

The Inmarsat C maritime mobile satellite system has an inherent capability, known as Enhanced Group Call (EGC), which allows broadcast messages to be made to selected groups of ship stations located anywhere within a satellite’s coverage.

Two types of EGC services are available: SafetyNET and FleetNET. FleetNET is a commercial messaging service offered by Inmarsat, and is not recognized by the Global Maritime Distress & Safety System (GMDSS). SafetyNET, along with NAVTEX, is recognized by the GMDSS as the primary means for disseminating maritime safety information. Ships regulated by the Safety of Life at Sea Convention travelling outside areas covered by NAVTEX have been required to carry an Inmarsat C SafetyNET receiver since February 1999.

Rigs have probably been the weakest link in seagoing vessels since the earliest days, and the first two days of Vendée Globe 2008 have been no exception. There’s a good reason for this: if you over-engineer the rig, the increased weight reduces stability, and hence the ability to carry sail. The Ocean 60 class rules take this into account by including a stability test, so the challenge is to produce a tall, strong rig for the minimum possible weight.

The stress analysis challenges are like those for civil engineering structures such as viaducts, only more complex. It’s easy to calculate the static loads, but what really matters in civil engineering structures is the resonances caused either by traffic or by high winds. Victorian engineering is littered with examples of failures caused by not understanding or being able to assess this. The damping effect of having a sail attached to it makes it a far less common concern for a mast, but there is a far more serious problem which viaduct designers don’t have to cope with.

Masts are attached to boats, and when the sea gets rough boats leap half out of the water and come crashing down – sometimes into a wave that is coming up to meet them, and possibly knocking them sideways at the same time. That’s what smashed masts in the Bay of Biscay this year, often after the wind had abated significantly.

Places like Southampton University’s Wolfson Unit are now highly skilled at using tank tests to assess the stresses on hulls, and modelling the way they react to those stresses. I don’t know of any group that has made similar progress in calculating the stresses on masts while attached to a freely moving boat. The number of degrees of freedom involved make for pretty computationally-intensive mathematical modelling, and the problem sounds too chaotic to model physically in a tank. How do you reproduce the kind of sea that builds up when strong winds shift through 90 degrees?

Racing in extreme classes like the Ocean 60 has helped collect the data that has led to class rules and  international standards, for hull construction and materials. I would expect it to contribute to similar standards for rigs at some future date. Certainly examination of the failures that have occurred in recent years will establish what probably caused them, but I don’t know of any boat carrying recording instruments that could give an idea of the actual stresses that occurred in specific incidents.

For instance, does any boat carry an accelerometer? Many years ago, offshore powerboats suffered serious damage without even hitting solid objects in the water.  In one case, a heat exchanger broke off and went through the bottom of the boat when it landed after jumping off a wave, and in another, one crewman finished a race with compression  fractures in both legs.

If there is anyone reading this who can point me in the direction of research being done on stresses on rigs in rough seas, I’ll be very grateful. It’s well beyond my own mathematical and computational skills, but I’d still like to read about it.

]]> http://www.newfreebooters.com/the-ocean-60-rig-pushing-the-limits-of-technology/feed 0 http://www.newfreebooters.com/introducing-a-new-category-the-good-old-days http://www.newfreebooters.com/introducing-a-new-category-the-good-old-days#comments Wed, 08 Oct 2008 12:26:02 +0000 admin http://www.newfreebooters.com/?p=67 Continue reading →]]> I’m getting a bit like my grandfather. I’ve been around long enough now to notice that some things have changed. I want to talk about the differences between then and now, and perhaps comment on where things seem to be going.

Note that I call them the good old days, not the better old days. I’m reminiscing mostly about challenge and excitement, and I don’t think there is any lack of that in today’s world – it’s just that the rules have changed, which stops life from getting boring.

There’s a lot of talk nowadays about over-protective attitudes, coming either from government or (influenced by the culture change) from parents. They certainly exist, but they won’t achieve what the protectors intend. Human beings always make risk judgements and act accordingly. There are well-documented examples of what can happen when you remove an obvious hazard in a road system – because it no longer looks dangerous, people drive faster and concentrate less. Sometimes, the situation gets worse than it was before.

Let’s forget the kind of nonsense that stopped kids from playing conkers and insists that anyone who takes other people’s children for a walk along a beach must have a life-saver certificate, and look at something more serious: clothing for sailing in cold weather in cold seas.

More than 30 years ago, Navy scientists established that no-one drowns in the English Channel. Wearing ordinary clothing, you die of hypothermia in about 30 minutes – even on a warm summer’s day.

I have no trouble believing that. I spent one such summer evening with several friends, searching Chilling beach for signs of a friend in his very early 20s, a strong swimmer, who had fallen out of a sailing dinghy a few hundred yards offshore while taking a novice for a sail. His body washed ashore the next day. He was wearing shorts, a shirt and a buoyancy aid, which was normal practice at the time (late 1950s).

During that period, I was one of several undergrad friends who competed for the fastest round trip from the Hamble River Sailing Club hard to Osborne Bay on the Isle of Wight, picking up a pebble to prove you’d been there, and back. We did it in a 12 foot Firefly dinghy, two up with no other boat around. I think a couple of other university club members knew what we were doing, but no-one waited around to see if we returned safely.

To stand a chance of beating the record, you needed a stiff westerly breeze (making it a planing reach both ways) and a tide stream that would help you in both directions. That made October or even November a good time to try. My best effort was made with John Turpin, a lad of Cornish fisherman stock (his brother wore a gold earring), just as penniless as most of us were. We wore oilskins and buoyancy aids, and did what we could to keep warm. Two thick wool jerseys and a university scarf soaked up a lot of the inevitable streams of cold water that poured down our necks. John’s secret weapon was several copies of the Radio Times stuffed inside his jersey.

Only a few years later, I had my first taste of the Burnham Icicle – a dinghy race held on New Year’s day on the Crouch in Essex. That year was windy as well as cold, and only one boat finished the course – the Jardine twins sailing a Flying Dutchman and wearing wetsuits. The only other boat which looked as if it would survive decided to retire, and the crew were helped back to the warm clubhouse while others pulled their boat up for them. From then on, Icicle rules required contestants to wear wetsuits.

Later, wetsuits became normal wear for dinghy sailing even in summer, and quite right, too. I enjoyed sailing as it was then, but the arrival of modern sailing gear has been a good thing.

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