A page of general info on passage-making from the Skylax blog, old articles and new musings.

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'Crossing an ocean in a small yacht is a bit like living your life backwards. At the beginning you die, then you get fitter and younger, and then when you arrive you have an orgasmic celebration and the idea that life is just beginning.'

It used to be the conventional wisdom that for offshore cruising a windvane self-steering gear was the first choice with autopilots the choice for inshore cruising. In recent years numbers of cruising boats have been setting out for distant shores and places with just an autopilot as the self-steering gear of choice so on my recent cruise to southeast Asia and back I dispensed with a wind vane gear and went down the autopilot route.

Actually my wind vane gear dispensed with itself a number of years ago. At the beginning of the season I had stowed the detached wind vane on the side-deck and tied to the shrouds which was fine until the jib sheet got caught around it and upon tacking flicked it 30 feet into the air and so to the sea bottom. Later on I was motoring up a channel that was being dredged where you had to wait until the dredger dropped the cable anchoring it to the opposite bank. In the windy conditions the operator panicked and tightened the cable a fraction too soon. It managed to catch the trim tab and in an instant I lost the bottom half of the wind vane gear. When it came to my refit for the Indian Ocean trip I plumped not too install another vane gear on Tetra and to carry just the existing autopilot and a back-up.

Reasons for and against

In the past the reasons for choosing a wind vane gear went something along these lines.

·         Wind vane gears are mechanical systems and can be repaired in most parts of the world where there are simple engineering workshops.

·         Mechanical systems are more reliable than electrical autopilots.

·         The gear doesn’t consume amps and therefore you don’t need to feed it by running the engine or a generator.

·         The gear steers a course relative to the wind which means you set up the sails and away you go on trade wind routes.

The first three reasons are no longer entirely true.

While it may be possible to have some parts of a mechanical self steering gear repaired using basic engineering skills, the parts that usually go wrong are often specialised castings (often in alloy) or specific items that must be replaced by the manufacturer. I have come across cruising yachts in all sorts of locations waiting for a replacement item to arrive so that a wind vane gear can be repaired. For some home-made trim tab gears it is possible to make running repairs in most parts of the world, but these are few and far between these days and most yachts have relatively sophisticated gear which incorporate cast alloy or injection moulded plastic components.

Lu installing the Type 2 drive in Skylax's lazarette

Mechanical systems are more reliable than electrical systems when all that salt water is flying around, but electrical autopilots have come a long way since the early days and they can take a lot of abuse before they expire. In most circumstances electrical autopilots cope well these days and if you think about the conditions the autopilots on the boats in the Vendee Global and the BOC round-the-world-races encounter, then autopilots are getting pretty thorough testing in extreme conditions. There is also the question of cost which I will come to later.

While it is true that a wind vane uses nothing but the wind itself for the energy to steer a boat, modern autopilots are now relatively economical in their power consumption. A lot of other items on board are going to be using a lot more amps to run. An Autohelm ST4000 (now the S1 + Grand Prix for tiller steered yachts up to 16,500lbs/7,500Kg) uses around 0.8 amps at 25% duty cycle. An Autohelm 8000 with a Type 2 drive (mechanical wheel steered

yachts up to 33,000lbd/15,000Kg)) uses 4-6 amps. The 8000 with a Type 1 drive (up to 22,000lbs/10,000Kg) uses 1½-3 amps.  Over a 24 hour period the ST4000 will use around 19 amp hours and the Type 2 linear mechanical drive around 120 amp hours. The latter figure is an average and most well set up yachts will use a lot less – probably around half that figure by my estimate. A refrigeration unit running for 6 hours (at 6 amps) will use around 36 amp hours, a 25 watt tricolour on for 10 hours will use around 21 amp hours, and an SSB transmission over 15 minutes will use around 6 amp hours. With modern charging units, wind generators and solar panels it is not too difficult to find the amps to feed an autopilot.

While a wind vane gear steers a course relative to the wind, an autopilot copes just as well when the wind direction is relatively constant over long distances such as in the trade wind belts. When the wind angle changes or a squall comes through, both gears need to be reset and in this there is no advantage for either except that it is comparatively easy to reset an autopilot with the auto-

course button. Some wind vane gears can be extremely difficult to re-adjust when the weather is rough and can involve balancing precariously on the aft deck to reset the vane. Others can be reset via control lines from the cockpit.

There are some reasons that go against the wind vane choice.

·         The initial cost of a wind vane gear is high with a lower end gear starting at around £1100 for a 10 metre boat and going up to £3,500 for some high end gears.

·         There are some yachts which just will not self-steer with a wind vane gear. A friend of mine with a moderately designed 37 foot yacht and a well known wind vane gear just cannot get it to work. He has tens of thousands of sea miles under his belt and is the pedantic sort who doesn’t like to let a problem remain unsolved. Despite advice from others and a lot of trying it just does not work. He is not alone and there are others who have difficulty, especially in downwind situations where the apparent wind is decreased just when the maximum effort is needed.

·         The gear clutters up the stern of a yacht which these days is cluttered up enough anyway with aerials, a swimming ladder, barbecue, life-saving devices and quite likely some fenders and ropes.

Making a choice

I think the old axiom of ‘if you can afford it, get both’ still stands. Most people have got so used to not steering a yacht on long or short passages that whatever works is good news. If you cannot stretch to both a wind vane gear and an autopilot, then the choice is more difficult.

On the trip from the Mediterranean to Malaysia and back in 1996-97 on Tetranora (31ft long keel around 7 tons) I took my trusty Autohelm 2000, now the ST4000 with added ingredients, which was already 7 years old and had a lot of miles under its belt. As backup I took an Autohelm 2000 all-in-one unit. The old 2000 lasted until the return trip back across to Sri Lanka when its motor packed up. There was a minor problem on the way when I cracked the end casing trying to remove it from the bracket on the aft deck, pure clumsiness on my part. Frank my crew mended this in Aden with a moulded epoxy casing he made up – he even bought a can of black spray paint so it looked a neat job. The new 2000 lasted until the Red Sea when it to expired and on inspection it was found that sea water had got inside and corroded the electronics making it impossible to repair.

You might surmise from this that the electric autopilot option was not the right choice. In fact I still believe it was and had I bought a new ST4000 instead of the ST2000, there would have been no problem. The new ST2000+ has also been beefed up with new silicon compression seals on the pushrod and most importantly a Gortex patch on the ‘breather’ under the body of the case. I suspect it was the latter that allowed water in as on the all-in-one 2000 I used there was no Gortex patch. Incidentally the old 2000 (now the 4000) was repaired in Turkey by the simple substitution of a new motor (cost around £40) and is again doing sterling work. Over 15,000 rugged miles a wind vane gear may have broken down.

On above decks systems one item that always gives trouble is the deck plug and socket. A good plug such as the dri-plug is adequate when there is just a bit of spray, but with any solid water coming on board all deck plugs just curl up and die. I had to replace the cockpit deck socket four times on this trip alone, although to be fair there was a lot of water coming on board for the first half of the trip.

To provide the amps for the autopilot I installed two solar panels on the bimini and at no time was I ever short of battery power. Mind you Tetra is an energy efficient boat to run without a refrigerator consuming all those amps, and in the Tropics I’m talking about a lot of amp hours if you want cold drinks. Other yachts I’ve talked to running autopilots only have often used both solar panels and a wind generator and have not experienced any lack of amps. On one Atlantic crossing a 45 foot yacht with an old American ‘windbugger’ could not get near the locking mechanism to stop it producing amps and had to resort to turning everything electrical on, the stereo, all the lights, anything that consumed power, until the gale died down a bit. It must have been an eerie sight in mid-Atlantic to see a yacht all lit up like a Christmas tree blaring out loud music in a gale. Newer models have a different mechanism so that this problem doesn’t arise.

There is also the question of cost. At today’s prices two ST 4000 gears would cost around £1200. Other comparable autopilots are around the same sort of price. The cheapest wind vane gear on the market would cost around the same as two of these autopilots and there is no backup if it breaks down. Moreover you will have to helm when motoring if you buy just the wind vane gear. You can set up a small autopilot to work the trim-tab ‘back the front’ as it were, when motoring, but this involves an additional cost buying a small autopilot.

On a small wheel steered yacht it occurs to me that there is no good reason why you couldn’t mount something like the ST4000 or similar down below on a small tiller bracket out from the rudder stock and have a small access hatch somewhere to engage or disengage it. This keeps the autopilot out of the elements with the only disadvantage being that it might be difficult to disengage in an emergency. On some yachts there may not be sufficient room to mount the autopilot at the distance specified from the rudder stock.

Whatever you get, make sure it works. On seven tenths we had two ST 4000+ units which were not up to the job of steering her downwind in the trades. On Sylax we have an 8000 unit with a Type 2 linear drive that after 18,000 odd miles is going well.

I can remember all too well what it was like to helm night after night on long passages in seven tenths. There are some who still do it, but they look shattered when they arrive. Self-steering of whatever type allows you more time to check your navigation, trim sails, keep a good watch and make lots of cups of tea. One thing that is important with an autopilot is not to trim sails too precisely when on passage. If the sail trim is a bit sloppy it allows the autopilot to get back on course without too much effort spent fighting the force of the wind in the sails when off course. When downwind if there is a lot of wind around I will often put a reef or two in the main which makes it easier for the autopilot to cope and in cruising mode doesn’t knock the average speed too much. And it is easier on the nerves if you are already prepared for any increase in the wind and easy enough to shake out if it all goes quiet.

2007 slightly adapted from an original draft from 1997.

 Fixing the 4000ST+ on seven tenths - yet again.

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Before leaving Lu makes up passage maps that we can use to plot weather, other boat positions off a radio net, dangers to navigation. We use Virtual Passage Planner to work up the scale of map we need and then put a VPP track on it for Skylax, but you can use whatever map you can get hold of as long as its got lat and longs on it. We then print off half a dozen or so on A4 sheets to use on passage. It saves drawing over charts, lots of rubbing out, and you can just use a new map when you need it.

For this trip we chose the area for the SW Pacific and printed them off (in B&W).

Passage map for SW Pacific

For more on Weather go to Weather

For more on Getting Weather at Sea go to Lu's Radio Page

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From Skylax blog 25-03-09

Passage Weather

Can't think why I've left this out of useful weather web sites as we use it all the time when we have a broadband connection. So go to

www.passageweather.com for what it says it does: PASSAGE WEATHER

For more on Weather go HERE

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Don't eat these fish

All At Sea, the free monthly sailing magazine in the Caribbean, had this informative guide on ciguatera in it's January 08 issue. If you can get hold of a copy it's worth holding onto for reference.

For fish recipes for edible fish see Gourmets and Gormands

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From the Skylax blog 15-04-09

El Nino, La Nina and ENSO 2009

The following is from Ocean Passages & Landfalls setting out briefly what El Nino, La Nina & ENSO are:

El Niño and La Niña

El Niño refers to an above average warming of equatorial Pacific waters and conversely La Niña to a cooling of these waters. El Niño is the name Peruvian fisherman long ago gave to these events and means the 'little boy' or 'Christ child' because an El Niño usually occurs around Christmas. La Niña means the 'little girl'.  A La Niña usually follows an El Niño, but not always. The warming of the waters produces high cloud activity which affects the jet stream high in the earth’s atmosphere and this leads to dramatic weather events as far away as the western Pacific coastline, the Indian Ocean and northern Atlantic. In recent years El Niño events have increased.

El Niño is important to yachtsmen because it disrupts normal weather patterns. In the South Pacific the trades are weakened during an El Niño year. In an El Niño year the North Atlantic is believed to experience fewer hurricanes while the eastern Pacific has an increased number. A La Niña year is believed to give rise to more hurricanes in the Atlantic. Tropical rainfall patterns are disrupted by an El Niño year and there can be droughts in areas like Indonesia and Australia and increased rainfall in normally dry areas like Peru. These changes in tropical rainfall patterns affect wind patterns and can lead to the late arrival of monsoons and to the trades decreasing in strength.

Although the exact relationship between El Niño and La Niña events and world weather are not fully understood, it is only prudent for yachtsmen to monitor whether or not an El Niño event is going to happen and look at possible predictions for out of the ordinary weather events. In a very simplistic sense an El Niño can point to the possibility of fewer early or late season hurricanes in the North Atlantic and light tradewinds in the South Pacific.

ENSO

El Niño and La Niña events lead to a see-saw oscillation of sea level pressure in the western and eastern Pacific. This is called the Southern Oscillation (SO). The SO is usually measured between Tahiti and Darwin. Because the SO is related to an El Niño event, the two terms are often combined to give ENSO. Many climatologists agree that the usage of all these names can be confusing and I mention ENSO here because it has become fashionable to use the term to describe what everyone else has been referring to as El Niño and La Niña events.

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2009

At present we are in a La Nina tending to ENSO neutral phase. Sea temperatures along the equator are still around half a degree Celcius colder than normal but have been tending to normal. (Source NOAA.) In a La Nina year there is an increase in the number of hurricanes in the Atlantic and in the number of Tropical Storms and cyclones affecting the east coast of Australia as well as the South Pacific basin generally.

So what is going to happen in the Atlantic?

The predictions for 2009 are for a normal year or a slight increase in the number of Tropical Storms and hurricanes for the 2009 season. The predictions are for 12 named Tropical Storms, 6 of those becoming Hurricanes and 2 of those Hurricanes becoming Major Hurricanes of around Cat 3 or more. (Source Colorado University – NOAA does not make predictions.)

And the Pacific?

With ENSO neutral or La Nina light the predictions are for increased rainfall in the western Pacific over Queensland, Indonesia and SE Asia. And tradewinds will be about normal or maybe a little less than normal.

This means we will be in for some lighter tradewinds, not a bad thing going into Cairns and up the coast and around to Darwin where the trades can blow more strongly than in the eastern and central Pacific. And it will be wet!

Predictions

These are all predictions. Some agencies are even predicting that in 2009 we will tip into an El Nino event in which case all these predictions can be tipped into the bin and we start all over again.

From the Skylax blog 15-04-09

Skin Cancer

Aussies and Kiwis know a thing or two about skin cancer. That ozone hole over the Antartica extends over Australia and New Zealand and they have had high rates of skin cancer for years. Extensive publicity in both countries has worked to some extent and visiting yachts headed down from the Tropics should take note. In Australia and NZ you are more at risk than in the Tropics and often you can literally feel those rays biting into your skin. Some of the below is adapted from my RYA Mediterranean Cruising but applies even more so to the Antipodes.

Skin cancer has increased dramatically in recent years, mostly because of the fashion for sunbathing and returning from a two week holiday in the sun with a tan. On a yacht you are at an increased risk of skin cancer because ultraviolet radiation is reflected off the water. Ultraviolet rays in sunlight affect our skin causing it to produce a pigment called melanin which gives the skin it’s colour. Sunbathing increases melanin temporarily but also damages the skin and can lead to skin cancer.

There are three types of UV radiation, UVC, UVB and UVA, but it is mostly UVA that we have to worry about. UVA is largely unaffected by the ozone layer and penetrates deeper into the skin than UVB.

The main risk factors for skin cancer are over-exposure to UVA and skin colour. Individuals with fair or freckled skin burn easily. Dark skins are at lower risk although they are still at danger from skin cancer.

There are a number of things you can do to decrease the risk of skin cancer. The Australian slogan ‘slip, slop, slap’ encapsulates the best advice which is

·         Slip on a shirt. It is important to know that a lot of fabrics like white cotton do not stop all the UVA hitting you. Darker fabrics and some specially designed shirts will cut out a higher percentage of UVA.

·         Slop on sun-block or sun-tan cream. Depending on your skin colour this should be a high SPF cream. For areas commonly exposed like the face and hands use total sun-block.

·         Slap on a hat. Wearing a good sun hat with a wide brim should become second nature. There are plenty of hats around with a good brim and a strap to hold on it on when there is some wind. Baseball type caps give some protection but not as much as a proper brimmed hat.

In addition to this advice think about the following.

·         On a boat a bimini keeps a lot of UVA from directly getting to you although some is still reflected off the water. A permanent bimini will radically decrease the UVA getting to you compared to getting grilled in the cockpit all day.

·         In harbour or at anchor an awning again cuts down on UVA exposure.

·         If you are snorkelling wear a T-shirt and waterproof sun-block or your back and the backs of your legs will be grilled. With the water lapping over you and cooling your body as you swim along the surface it is easy to underestimate how burnt you are getting.

·         Stay out of the sun over midday. This is the period when UVA  radiation is highest. If you are going ashore try to time it for after 1500.

Some UVA gets through cloud so even on cloudy days there is a risk of UVA exposure and you should ‘slip, slop, slap’.

Lu and Trina on Songline in the Hauraki Gulf in 06. Note hats and long sleeves. That sun really does bite.

AND MORE...

Skylax blog 28-04-09

Skin cancer and protecting yourself

These has been a good thread running on scuttlebutt about skin cancer and protecting yourself from the dreaded UV. I know a bit about this from an early scare when I was 23 and from recent biopsies and having suspicious bits cut out of me. The scuttlenutt thread is well worth a visit. There are three articles on recent scuttlebutts (24th,25th & 26th April) and some good forum posts on recommending types of sun block. Go HERE for the forum

The following is from my Adlard Coles Book of Mediterranean Sailing

Skin cancer has increased dramatically in recent years, mostly because of the fashion for sunbathing on holiday and returning home with a tan. On a yacht you are at an increased risk of skin cancer because ultraviolet radiation is reflected off the water. Ultraviolet rays in sunlight increase the production of a protective pigment called melanin which gives the skin its brown colour. However, even with the temporary increase of melanin, the tan does not prevent penetration of the skin by UV rays which can be extremely damaging.

There are three types of UV radiation: UVC, UVB and UVA, but it is mostly UVA that we have to worry about. UVA is largely unaffected by the ozone layer and penetrates deeper into the skin than UVB.

The main risk factors for skin cancer are over-exposure to UVA and skin colour. Individuals with fair or freckled skin burn easily. Dark skins are at lower risk although they are still in danger from skin cancer.

There are a number of things you can do to decrease the risk of skin cancer. The Australian slogan 'Slip, Slop, Slap' encapsulates the best advice:

•            Slip on a shirt. It is important to know that a lot of fabrics like white cotton do not stop all the UVA hitting you. Darker fabrics and some specially designed shirts will cut out a higher percentage of  UVA.

•            Slop on sun-block or sun-tan cream. Depending on your skin colour this should be a high factor SPF cream (at least factor 30 and preferably higher). For areas commonly exposed like the face and hands, use total sun-block.

•            Slap on a hat. Wearing a good sun hat with a wide brim should become second nature. There are plenty of hats around with a good brim and a strap to hold it on when there is some wind. Baseball-type caps give some protection but not as much as a proper brimmed hat.

In addition to this advice think about the following:

•           On a boat, a bimini protects you from a lot of UVA although some is still reflected off the water. A permanent bimini will radically decrease exposure to UVA in the cockpit.

•           In harbour or at anchor an awning cuts down on UVA exposure.

•           If you are snorkelling, wear a T-shirt and waterproof sun-block, or your back and the backs of your legs will be grilled. With the water lapping over you and cooling your body as you swim along the surface, it is easy to underestimate how burnt you are getting.

•           Stay out of the sun between midday and mid-afternoon. This is the period when UVA radiation is highest. If you are going ashore try to time it for after 1500.

•          Some UVA penetrates cloud so even on overcast days there is a risk of UVA exposure and you should 'Slip,Slop,Slap'. 

 Get a good bimini that can be left up when you are sailing as well as in harbour.