Beaufort Follies

I cannot take credit for this article, it was sent to me by a friend two days ago and I am amazed that I did not realise what he explained in his article, with my qualifications and experience this is something that I should have known about. I welcome any comments on it.

Martin.

I was curious about the way our excellent Kiss wind generator works. At wind speeds less than 15 knots it generates barely one or two amps, at twenty knots it generates a steady five to ten amps, at twenty three knots it generates fifteen amps or more, and at wind speeds much above that it starts to overload and freewheel. A good friend explained that the wind exerts its pressure on an area, so its power does not increase linearly with wind speed but in proportion to the square of the wind speed.
This set me thinking about how our passion for quantification can lead to terrible over-simplification with catastrophic consequences. The Beaufort wind scale provides an example.

Beaufort Force Knots Description

1 .................. 1 – 3 knots Light Air
2 ................. 4 – 6 knots Light Breeze
3 ..................7 – 10 knots Gentle Breeze
4 ................11 – 16 knots Moderate Breeze
5 ................17 – 21 knots Fresh Breeze
6 ................22 – 27 knots Strong Breeze
7 ................28 – 33 knots Near Gale
8 ................34 – 40 knots Gale
9 ................41 – 47 knots Strong Gale
10 ..............48 – 55 knots Storm
11 ..............56 – 63 knots Violent Storm
12 ..............64 or more kts Hurricane

This classification system, though it is in use throughout the nautical world, suggests that the strength of the weather increases more or less linearly with wind speed. But wind presses on an area and its strength increase with the square of its speed. Thus a twenty knot wind is not twice as powerful as a ten knot wind but four times as strong, forty knot winds are not four but sixteen times as strong, and eighty knot winds not eight but sixty-four times more powerful than ten knot winds. Such misperceptions caught out some of the experienced sailors in the 1998 Sydney to Hobart race. Five yachts were lost, fifty-five people were rescued and six people died. The inquest (according to the book “Fatal Storm: The Inside Story of the Tragic Sydney-Hobart Race” by Rob Mundle) found that underestimating the difference in severity of a gale and a storm was a significant factor in the tragedy. Judging by Beaufort numbers alone, the forecast storm (Force 10) would seem to be only 25 per cent more powerful than a gale (Force 8). If judged by wind speed in knots, the storm (48 to 55 knots) would be only 40 per cent more powerful than a gale (34 to 40 knots). But by the correct measure – the square of the wind speed – the storm was twice as violent as a gale.

Ian Kavanagh asks about bow a thruster, trim tabs, air-con & radar.

Martin,

I'm interested in buying my first boat which is a Sealine SC29 with twin 160hp Volvo duo-prop stern drive engines, the boat however does not have a bow thruster! You mention in your video "Buying a boat" that you do need a bow thruster especially with stern drive engines, which can be difficult to manoeuvre in the marina, would this advice also apply to a 29 ft boat or would I be ok without one? Also looking at trim tabs too, are these important on a boat this size? There are other options too, and I'm looking at what's important and what's not such as, air con, heating, auto pilot etc, so I have some reading up and decision making to do.

Thanks, Ian Kavanagh.

Ian,

Thanks for your email. The boat that you are thinking of buying is a very good boat, I have not driven one yet, but have just looked at the Sealine web site (http://www.sealine.com) and it looks very nice.
It will certainly be much better than a lot of other boats of that size that don't have a bow thruster. However berthing stern-to in anything other than a light wind will not be easy, particularly if the wind is blowing your bow away from the pontoon when you go into ahead to stop her. If I was buying one I would certainly ask Sealine for a quote for fitting a bow thruster, both 'Max-Power' (http://www.max-power.com/) and 'Vetus' (http://www.vetus.com/thrusters/bow_thrusters.cfm) are very good, it may not be as expensive as you think.

I am surprised that the SC 29 doesn't have trim tabs as standard, as the boat has stern drives the engines will be right at the back of the boat and the weight therefore in the stern so you will need trim tabs to bring the bows down when you get up on the plane and with a big following sea they will be useful to bring the bows up.

Unless you are going to bring the boat down to Portugal or the Med, I don't think air conditioning is necessary and if you have it you will have to have a generator too. Auto pilot is a nice thing to have if you are going to do any short hande long trips. If you are going to use the boat often in the winter in northern europe and spend time at anchor then 'eberspacher' is probably the best type of heating (http://www.eberspacher.com/marine1.php?section=marine), but if you are only going to stay in marinas then an electric fan heater is fine.
Please email me again if you think I can be of any more help.

Martin.

Thanks for the advice Martin. Have taken your advice about the bow-thruster and I am making enquiries about cost etc. According to Sealine's website trim tabs were under options! It did mention they were electric trim tabs so I don't know if they're different from normal ones, but if what you said about controlling the pitch angle of the boat/bows is right and I'm sure it is then I suppose it must have trim tabs of a sort. I thought trim tabs were to balance the boat longitudinally while under way, you know, if there was too much weight over one side of the boat than the other with people moving around etc.

Now seeing as my cruising area will be the Mersey and Irish Sea and that the SC29 is basically an open boat with a convertible top, useful in our inclement weather I think, then air-con is probably not really needed but the eberspacher may very well be so I will look into it. A generator may also be useful while at anchor. I will also specify a vhf radio and colour gps/chartplotter. It amazes me that a vhf is not standard fit on a boat of this size and price. Not sure about a radar, what do you think?

Thanks, Ian.

Ian,

Yes, you are quite right, trim tabs are for controlling sideways heeling caused by weight distribution or wind or both, but also for fore and aft pitch, in that when they are down they bring the bows down and the stern up placing the boat's hull evenly on the surface of the water to give you more speed and greater economy when planeing on relatively calm water. In bigger seas, particularly with a following sea you may find the boat is often easier to steer and less likely to 'trip over her keel' if you bring the trim tabs up and therefore the bow up.
Regarding the best make to fit, Bennett are by far the best and most reliable (http://www.bennetttrimtabs.com/), get the type that has a visual indicator NOT the automatic version. They are electric and hydraulic in that they have a small electric motor which drives a hydraulic pump on each one.

I completely agree with you re the importance of having VHF and chart plotter. I also think that it is very important to have Radar, whilst it is very usefull in the dark and in fog, it is also a very valuable tool for navigation in good visibility in that gives you a distance off which is so useful for avoiding shoals and rocks, whilst it may not tell you exactly where you are, it does tell you where you are not!! 'Raymarine' (http://www.raymarine.com/raymarine/) make a very good multifunctional chart plotter, radar and fish finder in two different sizes.

All the very best, Martin.

Links that are conspicuous by their absence!

I have added quite a long list of links to this blog. Most of them are builders of good yachts and motor cruisers. There are several very well known boat builders, mainly German and French, who are conspicuous by their absence. This is because in my opinion the boats that they build are complete rubbish and I would not recommend anyone to buy a boat from them.

One new owner of a yacht made by a very well known German boat builder complained so much about the defects on his boat that the local dealer in Portugal persuaded the company to send a representative down here to talk to the owner. After listening to a long list of complaints about the quality of this new boat, the representative from the company replied ‘You have bought the cheapest 50 foot boat on the market, what do you expect?’

Another horrifying story that I heard a few years ago from a delivery skipper was concerning brand new 44 foot yacht made by a very well known French boat builder. The delivery skipper and his crew were taking the yacht from La Rochelle to the Canary Islands. Unfortunately they were caught out in very bad weather (Force 10) for two days off Finistere, the volume production methods of this company involve bulkheads that are not properly bonded into the hull but instead just slot into pre-moulded slots in the hull and as a result of the hull flexing so much in these extreme conditions the bulkheads popped out and by the time the yacht reached the shelter of Vigo it was so badly damaged that it was decided by the boat builder and their insurers that it was a complete ‘right off’.

Needless to say I have not included the two boat builders described above in my list of links on this blog.

Exclusion from my list of links however does not suggest that a boat builder does not produce good boats. There are many I am sure that I have overlooked and also many excellent American yachts and motor cruisers that I don’t know anything about. Please email me and tell all about any good boats that you know of and include the web site, so I can look at their boats and include them in my list of links.

To hear more about my views on various types of boat see my video ‘Buying a boat’ on http://theiberianseaschool.com/content/view/15/26/

Training on your own yacht

I have been coaching people on their own boats for more than twenty years, sometimes for just one day, occasionally for as long as two weeks. (http://theiberianseaschool.com/content/view/19/30/)

Marina boat handling is a particular specialty. In just a day, I can transform your ability from ‘just average’ to ‘deeply impressive’. I thoroughly enjoy this work. It is very satisfying to see my clients now able to handle their own boat with confidence and style - in what previously was a difficult berthing situation. My fees are less than end-of-season gel coat repairs!

I teach people to go cruising. Out at sea, for longer periods, relaxed instruction in all aspects of sailing from sail trim to watch keeping to heavy weather tactics, in real not contrived conditions, builds well-found confidence. Most instructors do an exercise to simulate running out fuel, for example, but three miles from the harbour entrance, a client recently found that there was insufficient fuel for our return to Vilamoura (having assured his wife and me that there was plenty). This gave me an excellent opportunity to demonstrate berthing on the fuel pontoon under sail, and to follow this with instruction on bleeding the engine.

Sea Rage! I have frequently been approached by enlightened owners who aspire to become one of those good, easy-going, but responsible skippers, whose friends want to go cruising with them again and again. The reality is though that there are an amazing number of owners of yachts stuck on their own in marinas because no one wants to sail with them. They don't understand why, but I do, it is because they shout at their crews, because the responsibilities of command somehow turn very pleasant people into petty tyrants the moment they step on board. I call it 'sea rage' as it is a bit like road rage, it shows in nervous emphasis of unimportant things. Sadly, perhaps, we can't press-gang our crew anymore! So it is important to be nice to them and make sure that they enjoy their sailing with us, so that they will crew for us again and again.

My function is to guide owners and skippers into understanding what is important and what is not. Then that one percent of the time, when it matters they can still take firm command; but the other 99 per cent of the time they can behave normally, relax and enjoy themselves. This means sometimes allowing things to be done badly, in their judgement at least as skipper, and not criticising - self-restraint which many people find hard but it is vital if they are going to command absolute attention when it really does matter.

Unhappy partners. One of the most common dampeners of a skipper's pleasure in owning a new yacht is the seeming inability of his/her partner to share their enthusiasm. 'Sea Rage' may have something to do with it. But the competence and confidence of partners has also got a lot to do with it. I therefore pay special attention in encouraging partners to develop their boating skills. Given a chance most women will be as capable in boat handling as their husbands and some, of course, more so. It is no casual requirement that partners should become equally skilled, because there can be occasions at sea where illness or injury to the skipper mean they have to take over.

My role. In addition to formal courses (www.rya.org.uk/), I offer customised and discreet tuition. My role, as coach and mentor, is to help you build well-founded confidence, to gain increasing pleasure and competence as owner and skipper. I can help you learn things that you won't find in books because they are specific to my experience and your temperament.

My goal is to help you to become that marvellous thing, a capable and personable skipper, who manoeuvres a yacht with ease and panache, utterly reliable in a crisis and a pleasure to sail with at all times.

Martin (www.martinnorthey.net)

Martin Northey (Poem)

Dedicated to Martin Northey

It seems that many people
Have a dream to which they cling…
That one day they’ll own a cruiser,
…..‘cept they can’t drive the bloody thing !

So we bought this shiny Cranchi.
With its gleaming chrome and leather.
And we filled it up with diesel ,
And waited for good weather.

So then you seek an expert.
One who knows each trick and rule.
And one name , it kept recurring….
The Iberian Sea School !

He starts you in the classroom.
With a load of stuff to do .
Are tides “neaps” or “springs” you wonder,
And is that compass bearing true?

There are bowlines, there are bowsprings,
There’s a cleat, and clove hitch too.
There are flares and there are fenders,
There are flags of white and blue !

There are buoys and there are black balls.
There is anchor chain and rope.
And there’s how to check position…..
it’s all now within our scope !

And whilst much of it’s important,
And there is merit to each bit ,
With his humour and his patience ,
He makes sense of all of it.

Our first turns amongst the moorings,
Were not in whole devoid of fear !
And we had to learn quite quickly ,
When we’re “in” or “out” of gear !

And I guess like many couples,
I was cocky , she was scared !
But it took her just an hour ,
To do spins I’d not have dared !

And at times we lacked in judgement ,
And got our knickers in a tizz ,
But despite his swift instructions ,
He still claimed the fault was his !

I’m not sure about my colleagues ,
Who say “a bigger boat’s the game”.
‘Cos the diesel pump attendant ,
Already uses my first name !

So now we’re proud and confident ,
To use the expertise he gave .
And we can join the scores of boaters,
Who all greet him with a wave !

John & Julia , Bumbelady , Albufeira , June 2006 .

Fences not Ambulances

Not too long ago, I was asked by an inexperienced sailor for a couple of weeks training prior to an Atlantic crossing. He had already bought his boat on the advice of a friendly yacht broker who claimed that it was ‘just right for him’.It was a typical, modern, 44-foot, very light-displacement yacht.

On the face of it, he had done a good deal. The boat builder claimed in his literature that the yacht was suitable for an ocean crossing and it seemed to be good value for money. It had superb accommodation: eight berths, twin heads and the usual luxurious master cabin with a double-bed that you could walk right round. It had roller reefing on the mainsail and the jib and a complex system to bring the running rigging back to the cockpit. Extensive instrumentation provided a state-of-the-art GPS chart plotter system for navigation, with screens at the chart table, on the coach roof and just in front of the wheel.

He knew the boat that he had bought was quite heavy and that heavy-displacement boats are best in bad weather and that was what he thought he had bought. But he had made the common mistake of confusing a heavy boat with a heavy-displacement boat. Displacement is all to do with hull shape. The length and very wide beam of his boat meant that, despite its weight, most of it floated on top of the water, like a dinghy. Heavy-displacement boats have narrower beams (with the drawback of less-spacious accommodation). Because more of their hull is under water, they are much more stable in rough weather. Either the broker knew no better or, eager to sell the boat, chose not to correct his customer’s misunderstanding.

My heart sank. I knew his boat would bob about like a cork in even moderately heavy weather – a most unpleasant and tiring motion guaranteed to make almost anybody seasick. I knew that the rigging – adequate for short coastal hops – would be severely challenged by the Atlantic. I knew that the electronics would work fine as long as all the instruments functioned perfectly but that the maze of interfaces integrating different equipment meant that a single faulty instrument could cause the whole system to fail in a way that only someone with a PhD in Computer Science could hope to sort out.

How could I contradict a broker and a manufacturer and tell my client that the boat that he had bought was totally unsuitable for an Atlantic crossing when three-quarters of new boats - designed to look great at boat shows and expected to spend most of their life in marinas - suffer similar defects?

After two weeks training I advised him not to attempt the trip unless he left in December and took a minimum of two very experienced people with him as crew. He went ahead. The two people who went with him as ‘experienced crew’ proved to have a quarter of the experience that they had claimed. The crossing was arduous and terrifying, all three of them suffered badly from seasickness and exhaustion, the motion of the boat proved to be very uncomfortable and it’s violent slamming when sailing to windward put enormous stress on both the crew and on the standing rigging. The owner has since told me following his return from the Caribbean (by air) that the boat is now for sale in the Caribbean and if it doesn’t sell there he will get a delivery crew to bring it back, I for one wouldn’t want the job!

Another client spent a great deal of money on a rather lightweight 40-foot motor cruiser with stern drives and no bow thruster, he was told by the dealer that the boat didn’t need a bow thruster. He booked two days training with me, but because he had already had some training with me (on a boat with fixed propeller shafts) he decided to take the boat out prior to his instruction with me. Very sadly the boat was almost impossible to handle in a marina even in a moderate crosswind without a bow thruster and he damaged it quite badly by hitting a pontoon, terrifying himself and his wife, and immediately decided to sell it. (I am pleased to report that on my advice he has had a bow thruster fitted and after two days instruction with me his confidence is now restored, the damage has been repaired and he is now much happier about his purchase, and so is his wife!).

Others, with zero knowledge of boating, buy cruisers as fashion accessories to go with the villa on the golf course and the top-of-the-range Mercedes or BMW. For me to advise people after they have bought a boat is starting in the wrong place. What they need is ‘a fence at the top of the cliff not an ambulance at the bottom’. Thus maximising your boating pleasure must start with finding the right boat – and this means confronting some unpopular truths about many of the boats on sale today. Unpopular because boating is about dreams, and people don’t want their dreams to be shattered.

The truth is that manufacturers, driven by competition, are cutting corners to build to a price. Thus many new boats are not seaworthy in bad weather. And, if you look at the whole-life costs (including running costs, maintenance and depreciation), boats that seem to offer incredibly high specifications may prove a very false economy. For many, buying a new boat is as emotional and subjective a decision as buying a new car. We are influenced by advertising, brands, lines and fashion. But buyers need to beware – especially where their or their family’s safety is at stake. Boat manufacturer’s and brokers may not like to hear me say these things, but I am afraid that they will hurt their own market and therefore do themselves no favours over the long term by selling boats with such a high potential to disappoint.

Manufacturers and brokers have been listening to their customers - but the customers do not always know what is best for them. A cynic might recall the old quip about a certain computer company of whom it was said ‘they believed it was morally wrong not to separate a fool from his money – and they were very moral people’. Ultimately it is up to us, the customers, to do a much better job of understanding our own requirements and making sure they are met.

Nothing happens by accident!

Having put my rubbish in the rubbish container at 8.40 this morning I was walking back to my garage to get my jeep out in order to drive to spend the day instructing from Vilamoura Marina. Failing to notice a bollard that I must have walked past thousands of times, I tripped over it, cut my leg open and blood shot out of the gash like a burst water main!
30 minutes later I was in Albufeira hospital being stitched up. This was my first experience of a Portuguese Hospital, as I walked into the reception area without even breaking my stride (limp) I was ushered down a short passage and into a room where I was asked to lie down on a bed and within a minute my cut was being bathed and pain-killing injections were given followed by the cut being stitched up with about 15 stitches.

Half an hour after my arrival I left the hospital with a dressing on my leg, a prescription for antibiotics and instructions to keep the leg horizontal with an ice pack on it for 7 days! Plus I have to go back everyday to have the dressing changed.

The reality of my situation is that I have cancelled my work for today & tomorrow, but will work after that.

On my arrival at home I installed myself on my sofa with an icepack on my leg, and my lap top across my lap and began to make some changes to my web site (www.martinnorthey.net)
Having made a couple of important changes a great friend telephoned just to say hello, he had sent me details of 'blogging' a couple of weeks ago, but I did not realise what it was all about and had hoped that I would soon have an opportunity to talk to him about it all so I could understand a bit more about blogging and its advantages for me.

So here I am, with nothing to do for the next two days and realise that it is a heaven sent opportunity for me to find out all about blogging. So perhaps even this accident didn't happen by accident!