Saturday, 22 February 2014

Trans Atlantic log

I have transformed my trans-Atlantic log into a kml file viewable in Google Earth.

Saturday, 15 February 2014


I've already dealt with the toilet here. Switching to a 'composting' toilet has allowed me to remove a lot of pipes, valves, through hull fittings and a large storage tank. It's working well. Sawdust, pine needles or dry sea grass, as found along the high tide line of many beaches, all serve well as substrates. There's some satisfaction to be had by managing to simplify things without loss of function.

On the intake side, loading water has sometimes been awkward due to the unreliability of my engines - making maneuvering in close quarters hazardous. My preference to anchor for free in a river or bay as opposed to paying for a marina berth also limits my options. There aren't many anchorages with a fresh water tap available.

Many people have water makers these days. Salt water to fresh sounds ideal - there's no shortage of salt water out here. However, water makers are expensive, require a lot of power to run, need operating regularly or their workings become gummed up, and can only be used where the salt water is clean - which isn't the case at every anchorage (not everyone uses a composting toilet or holding tanks).

So, I have been relying on my rain-water cating system, which I described installing here.

Of course, crossing the Atlantic, I couldn't rely on rain water. It might well have been dry all the way across. As it happened it probably rained every day after the first week, and often in such quantities I could have refilled my tanks many times over. I simply had to carry enough water to get me across, plus a contingency. (I actually carried far too much for too long - mistake!). But even here, having a supply of rain water available to supplement my basic supply would have allowed me to have plenty of showers and do all the laundry I wanted - if I hadn't been preoccupied with more pressing needs at the time.

Since arriving in the Caribbean a month ago, I haven't needed to find a tap anywhere, and my tanks are currently half full. It rains often enough to supply all we need. And we swim every day, and shower afterwards. We're pretty good at using small quantities for washing up, and use a pressure cooker a lot - which needs very little water.

I'm set up so that I can fill containers from a tap - one in each hull - when it rains. A decent downpour can give me 100 litres - I have 4 x 25l containers, and so far haven't felt the need to go out in the rain to empty the containers into the tank for a refill. I have considered plumbing the taps directly into the tanks, via a filter. It's still quite a bit of work lugging the containers onto the deck to fill the tanks. However, I've sometimes forgotten to turn off the collecting taps when I've gone sailing, and a bit of sea spray is enough to contaminate a tank of water so that you wouldn't want to drink it. So there is some benefit of manually emptying the containers. I get the chance to taste the water if I have any suspicions of contamination. And containers of water are handier for doing the laundry, which we do in a great big bucket on deck.

Seabirds don't seem to be in the habit of sitting on boats around here, which eliminates a major source of contamination. However, my decks aren't perfectly clean, and rain picks up dirt in the air, so I add a little thin bleach to each tank - diy chlorination.

Friday, 7 February 2014

Boat electricity

I'll post some more about our sailing experiences later,  but I said I'd go through the boat system by system, and let you know what worked out and what didn't. So here's how it has worked out with electricity on board.

I was invited to dinner on a doctor's boat. A clever man. The engine was running when I arrived and the wind generator was clattering around making quite a racket, disturbing until alcohol soothed the nerves and lubricated the conversation. I asked why the engine was running (after an hour or so) and was told it was to charge the batteries. Ah, so the wind generator is broken then? No, the rattling noise is just the hub in the middle, a little loose. Something he hadn't got round to repairing. He'd got used to the noise. The wind generator was beside the solar panel array. The engine ran on. He ran it he said 2-3 hours a day like that, faster than tickover. I suggested that if the batteries needed that much charging, perhaps his batteries were dud. No, he replied - as soon as the engine was running, the battery voltage went up to 14V.

So, a clever man with an array of solar panels and a windmill, in the Caribbean with all its sun and wind, needed to run his engine up to 3 hours a day. For what? His LED lights, a fridge and his iPad. The clever man knows very little about batteries and charging, and I've found this very common indeed amongst yachties. The subject is dull and technical and it isn't sailing, and very few people know what you need to know to live comfortably off-grid. If you'll tolerate a little technicality, and I'll try to be as brief as possible, I'll tell you all you need to know.

HandyBob's blog taught me a lot! Got me on the right track. I recommend you reading it sometime, but it is verbose. Here is a summary:

  • Every time a battery goes through a discharge/charge cycle without being fully charged, it loses some of its storage capacity.
  • You cannot tell a battery's condition by measuring the voltage.
  • A lead/acid battery can only accept charge at a certain rate - a rate which diminishes as the battery becomes fuller. When the battery is nearly full, it still needs to be filled further, but you can only do this by feeding it in slowly.
  • If a battery loses some of its storage capacity, this is caused by the plates becoming sulphated. The plates are designed to be porous, but if a battery isn't charged fully after each discharge, the plates become sulphated - that is, a hard less porous crust forms around the plates. You'll still measure a high voltage on the battery after charging, but you won't be able to draw current for long. The battery's capacity to hold charge is diminished by the crusted plates.
  • A battery that has lost its capacity to some extent can be repaired by deliberate and careful overcharging (equalisation). Equalisation can be harmful in excess, and in vented lead/acid batteries, water is lost in the process and needs topping up afterwards. A battery that has been kept undercharged for too long is knackered.
  • And, voltage drops caused by using undersized wires between the power source, controller and batteries can reduce the voltage getting to the batteries by enough to ensure that the batteries are never fully charged, and their useful life will be greatly shortened. 

I have a friend who was literally born on a boat and has always lived on boats. He is often short of electricity and simply replaces his batteries every year, at great expense. What a waste!

Batteries need charging in stages: bulk, absorption, float and equalisation. The voltage supplied to the batteries by the charge source is different for each of these stages. Different brands need different voltages applied to them for the various stages. I use Trojan T-125 6v batteries, two in series to give me 12v. For whatever batteries you have, you need to know these voltages (the manufacturers usually publish the specifications of their batteries on a website) but they'll be similar to mine, so I'll use their voltage recommendations in the following description.

Bulk charging is used when the battery is depleted. The battery can accept all the charge you can throw at it, up to a maximum current capacity which is limited by the size of the battery - rule of thumb, the current should be no more than 20% of the battery's amp-hour capacity, that is 20 amps max for a 100 Ah battery.

As you charge a battery, the voltage across the terminals increases. When it reaches the absorption voltage, it needs limiting to that. You don't want the voltage getting above that or you'll damage the battery. With my battery setup, that voltage is 14.7 volts. That voltage needs maintaining till the battery is fully charged. Lots of chargers - engine alternators in particular - don't reach this voltage, and so running an engine to charge your batteries isn't good enough. As the battery fills, it takes less and less current. When the current is small enough, down to an amp or so, the batteries are full, and it is time to switch to the float voltage.

On my batteries, the float voltage is 13.2 volts. The battery won't lose charge if it is held at this voltage, and won't use water either.

Equalisation needs doing occasionally, and there is a good description of that here. No need for me to repeat what is written there.


Naturally, you want to spend as little time as possible watching voltages so you can do something more interesting, like watch paint dry. So you need a controller between your powers source (solar panels, windmill, whatever) and your batteries. A good controller will deal with feeding the batteries the right voltages for the right amount of time. A good controller will limit the current supplied to a battery using pulse width modulation (PWM). Others just dissipate the unused power as heat. PWM is what you want - you get less sulphation with PWM. What you also need is a controller that allows you to set the correct voltages for the batteries you have now or may switch to later. A controller that doesn't allow you to set these voltages (setpoints) is a waste of money.

I bought the cheapest controller I could find that used PWM and allowed me to set the voltages - a SunSaver Duo controller. I've got it set up and running fine, but it certainly isn't ideal. For one thing, you can't choose when to equalise the batteries with this controller. It is preset to equalise once a month. If I've had a run of cloudy days and used a lot of power, I want to equalise again when the sun comes out, not when the controller says a month is up since the last equalisation. And if there has been plenty of sunshine, and I haven't used much power, I don't want to equalise at all. And if I am out sailing and I have all my instruments running and the VHF and AIS and so on, I don't want the controller to start equalising, because the voltage will go up to close to 16v, which might well damage some of my electronics. When I equalise the batteries, I need to do it when it needs doing and when I don't have any sensitive equipment switched on. And besides this, the recommended equalisation charge for my Trojan batteries is 15.48v. When I set up the controller to use this voltage, I got an 'over-voltage' error. On contacting the manufacturer, I was told that although the SunSaver Duo can be set to this voltage, the protection circuit which is nominally set at 15.5 volts will cut the power somewhat sooner. So it simply can't supply the required voltage.

Setting up the correct setpoints for my batteries is possible using a meterbus from Morningstar, which is a thing that connects the controller to your laptop. Here you can set the voltages stages, and you can also see what state the batteries are in.

How I get round the equalisation problem is to connect a solar panel directly to the battery when I need to equalise it, and regulate the voltage myself by tweaking angle of the panel to the sun, or partially covering it up. It's a pain, but I don't need to do it very often, and I can usually manage to do it when I have other jobs to do around the boat.

Perhaps I should have simply bought the more expensive Morningstar Tristar 45 Handy Bob recommends, but here's another issue.

When a battery reaches the absorption stage, some of the available power is being dumped by the controller. My solar panels have a maximum output of around 12 amps at 13 or so volts. But usually, there is 4 or less amps going into a battery. Much of the available power of my panels isn't being used. So I now have two battery banks - previously I'd ignored the Sunsaver Duo's capacity to manage two battery banks. Every day I switch my battery selection switch to give each battery bank every other day off duty. This allows the controller to pour most of the available power into the battery currently in use and at the same time, top up with other battery with the small current needed to fully charge it. This is how I manage to ensure my batteries reach full capacity and I don't waste too much of the power available from my panels.

By the way, this is how I found a friend's batteries were badly sulphated. My friend has a similar boat, and like me, a couple of solar panels but with a higher power output. He told me one day he was pleased with the panels as they were currently giving him 5 amps. He asked how much mine were giving. I looked at my gauge, and it told me 12 amps. He found this difficult to believe. His batteries showed the same voltage as mine. What was going on? His batteries were sulphated, so they couldn't absorb much current. He badly needed to do an equalisation to restore his battery capacity.

Power sources.
A boat engine mechanic told me that he reckoned most of his jobs were the result of people running their engines to charge their batteries. He reckoned running a diesel engine without a load (the load of an alternator is tiny compared to the load when an engine is powering a boat through the water) was the quickest way to wreck it. The engine runs cold, and the fuel doesn't burn as completely as when it runs hot, and the deposition of carbon and other substances gave the mechanic plenty to fix. Another problem with using an engine alternator to charge the batteries is that often the output voltage is limited to 13.5 - 14 volts or so - enough to put a useful amount of power into a depleted battery, but not enough to fully charge it, no matter how long you run the engine.

Windmills. A very long time ago, I was the first yachtie to install a Rutland wind charger on a boat. At the time, it supplied far more power than all the others around at the time, which were mostly trickle chargers that could top up a battery in a gale. I was a fan. However, the blades can be noisy (some you can hear right across an anchorage!) and when the bearings start to go, they are noisy too. I used to change the bearings a lot on my old Rutland. I believe their design has improved since then, but still, moving parts, noise, wear and tear. Solar panels have become far more efficient than they used to be and far cheaper. So now, it is just solar panels for me.

Solar panels.

Just great, so long as you have some sunshine. And an unshaded place to put the panels. The doctor had his panels on a frame at the back of his boat. The wind generator was mounted on one side of frame. On the other side of the frame were various antennas. So there was almost never a time when the solar panels were in full sun. It's handy to have a couple of ammeters on your electrical panel which shows how much current is going in and how much current going out. If you haven't tried this already, you'll be amazed I think to shade a solar panel just a little and see how much that reduces the current going in to the batteries. The shadow of a rigging wire across one of my panels is enough to reduce the power output to nearly half. And to get full power from the panels, they need to ideally face the sun, or at least be orientated to within 30 degrees of directly facing the sun. Most solar panels on most boats spend a significant time shaded. If you insist on having mounted panels, you need to take account of this, and buy more panels to make up for the loss of power.

When I bought my boat, I intended to build a raised area at the back for a couple of solar panels. But I found out about the size of the shadow effect, and I also wondered how I could arrange things so that I could tilt the panels. I imagined my Atlantic crossing, with an array of horizontal panels. They wouldn't give full power till mid-late morning. Then they'd be shaded by the sails, and they'd give almost nothing. There's nowhere on a sail boat that doesn't have a shadow over it at some time. In the end, I decided to keep my panels mobile, and though sometimes it is a hassle moving them about I don't regret that decision.

I can put my panels anywhere on the boat. They have long leads that connect via MC4 sockets and plugs. I have a pair of sockets at the back of the boat and a pair inside an anchor locker that has a notch in it to accommodate the leads. The leads are very thick - the copper needs to have a cross-sectional area of 4 square millimetres. Otherwise too much power is lost as it is transmitted along the leads. Crossing the Atlantic, I tied my panels outside the guardrail on the port side, so that soon after sunrise, they were in full sun. Mid morning, I usually moved them onto a part of my roof that faced S-SW on that route. That was often enough exposure, which is good, because from mid-afternoon onwards almost all of the boat way in the shadow of the sails (in light wind anyway). I did have a spell of particularly cloudy weather mid-Atlantic, where try as I might, I didn't manage to fill my batteries each day. On those days, I went to extremes, and tied one panel to the outside of a pulpit on the port hull, and the other, well...

Currently I spend most of my days at anchor in the trade winds, and so never have to move my panels. They are both tied to a part of the starboard coachroof that isn't affected by any shadow till late afternoon, and then it is only a rigging wire a few feet away. I don't need a noisy generator, to run a diesel engine or have a noisy wind generator. True, I don't use much electricity. I can generate and store much more than I currently use. I'm considering using that spare capacity to run a fridge.

Another useful aspect of keeping my panels mobile is that I can store them indoors (against the bathroom wall, held in place by a towel rail) when the weather is rough, when I don't need them and they might get in the way or when I am in an area where they might be stolen.

So, I seem to have the electricity issue pretty much sorted out - bar the hassle of having to monitor my battery state and equalise them manually now and again - but I wouldn't recommend you do what I've done!

If I was to start over, I'd switch to lithium batteries. They're much more expensive, but much lighter - weight per Ah capacity, and they can accept charge much faster than lead/acid batteries, which means that if you have your solar panels charging and run the engine too, the lithium battery can just keep on absorbing pretty much all the power you can throw as it until it is full - no need to taper the current as the battery fills. This means that to some extent, the extra you spend on batteries you can save in have fewer solar panels. The panels you have will always run at close to 100% efficiency until the battery is full. This better ability to accept charge also allows you to either fit a much bigger alternator to your engine, or install a separate generator driven off the engine. The engine will then run under some load, and so won't run cold if you just use it for charging, and you will need to run it for much shorter periods. Anyway, here is a more fully formed opinion on the matter, from a fellow who has installed lithium batteries on his boat.

Monday, 3 February 2014

Las Palmas to St Lucia

2800 miles in 21 days. I was single-handed, so some nights when the wind dropped, I left just a small amount of sail up and didn't bother myself with speed. The main issue I had to deal with was slowing the boat down in big waves, without going too slow in the troughs.

The wind was from dead astern all the way (I set off with a good forecast, unlike the ARC people who set off two weeks earlier and had a week of no wind and contrary wind on setting off). The first 1000 miles was fine with fairly light winds, up to max F5-6.

Around 1000 miles out, I saw a signal from a boat that was doing just 2-3 knots on my laptop. Thinking it might be a dismasted yacht, I changed course to meet it. It turned out to be a man in a rowing boat. The closer I got, the more anxious he became that I might run him down (it was night) and I realised at last that though I could hear his radio fine, he couldn't hear mine. So I turned away again to let him sleep. A man in a 7m rowing boat out there! Most likely he is still there, still rowing. I remembered him fondly whenever fear inclined towards self-pity (those dark and stormy nights).

Jib and Genoa poled out.

I found twin headsails to be just the job. I used my spinnaker and the mainsail on just one day - on all other days, the main was left under cover. What would have been nice is roller furling with twin luff grooves and a pair of genoas, but, well, I don't have that extra complexity, expense, weight, windage and convenience. My sails just hank on, but I found a neat way of dealing with it.

I numbered the hanks on each sail with coloured marker pens so that I could attach any two sails to the forestay, interspersing the hanks without them fouling. I attached a block to the jib halyard, and attached the heads of the two foresails with a short strop that lead through the block. This allows the tension from the halyard to be divided evenly between the two sail luffs. That worked well.

1000 miles of this.

I caught a few dorado - stopping the boat, or slowing it to 2-3 knots anyway - was just a matter of opening the halyard clutch and both sails would drop in a moment onto the net.

A Dorado lying beside a really huge green funnel.

The fish are much more easily reeled in with the sails dropped. Hoisting the sails back up again was straight-forward too. Most of the way I could pull both sails back up by hand, needing a winch only for the final tensioning. I didn't have to mess with the sheets at all. However, despite the pleasant and favourable winds, I remained anxious about what to do in the stronger winds, which is what I had for the next 1700 miles...

Surfing was scary. I don't know what speeds I had. At the fastest speeds, I certainly wasn't looking at the laptop. I've previously seen 18 knots with no sail up, and that was just in a F7. Squalls were dramatic, and most days I had some, sometimes maybe 6-8 a day! In one, on a moonless night, I dropped all sail and was doing a very steady 11-12 knots with no sail up and no surfing - the wind was so fast and so localised, it didn't really build any waves. It was more like driving over corrugated water. That lasted half an hour. Another time a wave got the boat surfing to my great surprise - because I'd hardly surfed at all in the previous few hours - and it went so fast it ended in a nose-dive, with a lot of green water over the roof. That was the scariest bit. I think there was quite a bit of cross-swell at the time, and lumps of water would appear where the swells coincided. I guess one of those lumps appeared in my path while the boat was surfing.

Anyway, to cut a very long story shortish, the answer to my excessive speed was not simply to reduce sail. In strong winds the boat could still easily start surfing with little or no sail up if the waves were big and steep enough, and it would just go too slowly in the troughs. The answer is the Abbot drogue. Dave Abbot wrote about this on his website, but I hadn't appreciated how useful this drogue would be with sail up. I had assumed Dave was writing about just slowing the boat down after he'd taken all sail down. Sail up AND drogue out - that was the answer!

I already had a pair of steel plates at the stern for attaching a Jordan series drogue. I used these to attach an Abbot drogue instead, with a slight variation on Dave's scheme. I attached one end of a long rope to one of the plates, and led the rope through a block attached to the plate on the other side and then up to a sheet winch. 10 metres of chain was attached to a length of plastic pipe that went over the rope. I put a knot in the rope a few metres from the end, so that when I winched the rope in, the knot would snag the pipe and the last bit of rope and chain could be pulled right up to the block, making retrieval easier.

One end of the Abbot drogue attached to my drogue plate.

A short bight of rope. At the end of the bight is a bit of water pipe that slides over the rope, and 10 metres of chain tied to that. Even this length of drogue significantly reduced my maximum surfing speeds without reducing my average speed that much. More rope was let out as the waves got bigger.

On the other side of the boat, the bight of rope is passed through a block attached to the drogue plate...

...and to the sheet winch - which made it easy to retrieve,

I found that it was pretty easy to find just the right length of rope that would take the top off the maximum speeds, but not slow the boat significantly in the troughs. The self-steering did a much better job with more stable speeds. With a set up like this, I'd average 6 knots, varying between 4 and 8-10. That was actually pretty comfortable, and with no rolling of course. My speed was now easily adjustable, and surfing was controlled. Quite often there'd be cross-swell, and the seas would be very uneven, so I would sail quite slowly through those periods. When the seas were more even, I could pull in some of the drogue or put a bit more sail up to allow a little surfing - but it never got out of control again.

1700 miles of this.

The degree of control that the drogue allowed was a revelation. The drag that the drogue produces is of course relative to the speed that it goes through the water, but a doubling of speed should quadruple the drag (I think that's how it goes - that's certainly how it seemed). So the drag is quite low at low speeds, and rapidly increases at higher speeds - meaning that by adjusting the amount of sail and the length of the drogue, very even and reasonable speeds could be achieved.

Still, despite my easy sail handling and adjustable drogue, the winds were ridiculously variable in speed for that last long stretch, and I was never able to predict whether they'd get stronger or weaker. So I did spend a lot of time some days doing sail change after sail change.

Squalls were very frequent for about 10 days of the trip.

At first, I'd just drop all sail till it blew over, but this seemed a waste of wind, and sometimes if there were big waves, the boat could be knocked side-on to the waves and the self-steering was then unable to get the boat back on course. This required me to go outside in the howling wind and rain and raise sail, drop a dagger-board and get the boat back on course, the drop the sail and raise the board again.

A better solution for dealing with squalls was to put up the storm jib on the inner forestay, and leave it there, no matter what other combination of jibs I had on the forestay. When a squall hit, all I had to do was open the clutch to drop the jibs on the forestay and leave the storm jib to provide good steerage way through the squalls. After the squall, I just raised the pair of jibs again. Quite often, a squall would pass in this way and no speed was lost at all. The storm jib would keep me going at 6-7 knots, and when the wind started to diminish it was a simple matter of raising the jibs on the forestay again.

I moved all the chain and anchors from the bridgedeck anchor lockers to the floor of the bathroom. That improved the ride quite a bit. And I dumped a lot of the water I was carrying. I had far too much, especially as once I was being hit by squalls, I could very easily catch as much water as I wanted from the guttering I'd put round the coachroof. I set off with 350 litres. I reckon I only used 50 or so, so that was 300kg of useless weight! I rather stupidly carried that for almost 1000 miles!

That was it really. There's a big emptiness out there! I was accompanied by Minke whales for a couple of days, but apart from the occasional bird and dorado and later the flying fish I saw no other wildlife and had no human contact either. 25 miles out of St Lucia, a man said hello me and nearly caused a heart attack. I was busy sail changing, sitting on the net at the time, and I hadn't looked around. There were  a couple of blokes on a very colourful little open boat close by, fully dressed in waterproofs and balaclavas. I was sweating in a pair of shorts.

I used an AIS transceiver and a Merveille radar alarm. I never saw another boat that one system or another hadn't previously alerted me to. It's just the little fishing boats you've go to keep an eye out for I guess!