07/07/2012, 17 miles from Dundas strait
What a difference a day makes.
Yesterday at this time we were sailing along nicely in rolling seas and today we are motoring along in conditions that remind me of "The Rhyme of the Ancient Marriner". You know the one,,"...water water everywhere but not a drop to drink"
Seas are flat, our motoring is making all the wind we are experiencing and we have already started feeling the effects of the tidal currents that flow through Van Diemen's Gulf.
Darwin has a very large tidal range. We expect to see 13-15 foot differences between high and low while we are there. All that water has to flow in and out through some constrained passes and hence the tidal currents we are concerned about.
We have a cruising guide to the Northern Territories and it says that we we are at the entrance to the Dundas straits about 4.5 hours before high tide is Darwin that we have a shot at getting through the gulf in one tide. Unless we slow down a lot more we should be in position for that to happen. Assuming I have the tidal info for Darwin that is correct. Two of the programs we have agree so Im reasonably confident.
These sorts of conditions must have been terrifying for Matthew Flinders and the other early explorers. Having their ship seized by strong tidal flow that crosses shoals and not having any wind to give them some speed through the water to let them steer would have been scary for them. Having a reliable diesel engine makes a big difference.
The diesel is becomming more and more expensive to operate so we tend to wait until we are going less that 1-2 kts before we resort to it. Of course when we are in the middle of an ocean we dont have enough fuel to get us anywhere so we just sit there and wait for wind.
There is not a lot of other news to report today
07/07/2012, Van Diemen Gulf
Ham radio operations have a long tradition of public service and in the past they were very valuable channels of communication during times of natural disasters. Modern cellular phone technology and satellite communications has rendered that role for HAM operators less important but many have found a way to add value by operating stations that let those of us at sea communicate with our friends and families and get critical weather information when we are thousands of miles from land.
Those of you who write to us via our HAM radio link know that our address says @ winklink.org. Winlink is a volunteer organization that writes the software and manages the servers that make all of this possible. In 4 years we have been crossing oceans I can only remember two times when technical difficulties delayed communication and the station I connected to told me what was going on and when it would be fixed.
After my years of participation in home owners' associations and yacht clubs I am quick to say "deliver me from volunteers". Very often the volunteers have an agenda of their own and dont play well together. Winlink and the amateur radio community are the opposite. The volunteers are technically competent people who work well together . If there are times they do battle they keep in out of sight. They build consensus and move the technology forward without a lot of obvious politics. From my perspective the system works extraordinarily well
We passed a milestone in our travels. Yesterday afternoon the nearest winlink station for us to connect with is no longer in Australia. Its in Indonesia.. The program that manages the sending and receiving of our emails over the high frequency radio automatically sorts the available stations based on distance. Early in the day yesterday two station in Australia were the closest ones (Sydney and Melbourne). When I logged on to get our evening weather information that had changed and now there is a station in Indonesia that is closer. It works very well so Im hopeful we will have good communications as we start our crossing of the Indian Ocean.
The stations we connect with are operated by volunteer HAM radio operators who build their stations, at their own expense, and watch over the operation of the station most of the time. Much of the modern equipment is automated and some stations, like the one in Indonesia, are actually located remote from the operator who monitors the operation over the internet.
Most of these stations have tens of thousands of dollars in equipment in them and, even more important, the stations benefit from the expertise of the operators making sure that everything works. Using these station s cost us nothing. These stations manage the high frequency radio communication between our radio on the boat and their shore side equipment and then take our messages and send them on the internet to their intended recipients. The process is so fast that I have sent position reports to winlink over the radio and seen them appear on our tracking page as quickly as the page can load over the internet.
After we get out into the Indian Ocean the the pickings get slimmer. When we crossed the Pacific from Easter Island back to Peru I found that I had to be more disciplined about the times of day when the bands were open. The skip of the signal off the ionosphere is better when the sun is directly overhead about halfway between us and the station we are trying to reach, but there are exceptions that I dont understand. Radio propagation is part physics and part magic.
The software has a propagation tool that pops up when needed and tells me which frequencies are most likely to work for which stations but sometimes that is wrong too. The predictions are based on mathematical algorithms that use the locations of the two stations (us and the one we are trying to reach) along with the time of day and the predicted state of ionization of the atmosphere between the two stations. The software even downloads data about sun spots when I log on. Sunspots are good for high frequency radio communications because they send ionizing particles into our atmosphere that makes the upper layers more reflective.
When the predictions are proven wrong in practice I think the big determining factor is the quality of the antenna at the other end and what direction the operator has it pointed. We use an insulated part of our backstay as an antenna and its a compromise at best. Fortunately the people operating the shore side stations have the space to build much better antenna systems that really help us out.
Other factors that impact our ability to communicate via high frequency radio are sources of radio frequency interference (RFI) on the boat. Our fridge compressor sends very distinctive noise into the radio. I can hear it and know it well. Sometimes I pull the fuse on our fridge to keep the radio working better. Other times the fridge RFI might slow things down but does not make it impossible. Another source of RFI is the charge controllers for our solar panels. They are a real problem sometimes and much harder to disconnect than simply pulling a fuse. Even the GPS receivers put out RFI that can be heard on some frequencies. As our watermaker ages the brushed DC motor on the high pressure pump gets more and more radio noisy.
After a few years of using these stations to send and receive email I have become used to some of their idiosyncrasies. I have a pretty good sense of how long it will take the station I connect with to swing its antenna around and point it at me. The quality of the signal increases as the aim of the antenna gets closer to us and that allows the software to boost the speed at which the data are sent and received.
We use winlink to get high quality weather information, send and receive emails with family and friends, and submit position reports so people know where we are,
Our shipboard computer does all of this via an interface between the computer and our Single Side Band Radio. The program that manages all of this is another piece of free software called airmail. I'll talk about airmail in another blog entry where I can upload screen shots to help with the explanation. Airmail is written and maintained by Jim Corenman and he gives it to the cruising community absolutely free.
07/05/2012, The Arafura Sea
The wind is getting lighter this morning. It also seems to be shifting around to the East so the high is probably moving out of the Great Australian Bight. We are waiting to see if the change is going to stick before we shake the reefs out of the main or pole out the yankee. In the meantime we adjusted our course to keep the yankee happy and will compensate later.
The seas have also calmed down quite a bit.
The tides here in the Arafura Sea seem to run more east and west that those in the Gulf of Carpenteria that ran north and south. Since we are on a westerly course we are helped by the tides and then they are against us for a while.
Our wind sensing instruments at the top of the mast got whacked by a bird in Tasmania. Shawn straightened it out the last time he was up the mast but the calibration loused up. Today I finally got around to getting out the manual and adjusting the calibration as well as I can until we are in flat water and can go through the complete calibration process.
We are 73 miles from the point where we start turning a little more south to head toward Darwin and about 240 miles from our anchorage in Darwin.
Since there is not a lot of news I thought I would use today's blog to tell you about one of the culinary techniques we learned about in Peru.
The Peruvians are as particular about food as the French and have the most beautiful produce we have seen anywhere. Once you have had an avocado in Peru you will be forever unsatisfied by what you find other places.
If you really want to annoy a Frenchman just tell him that Peruvian A la Cena store bought mayonnaise is as good or better than the homemade kind the French make. In my experience, its true.
The only thing the Peruvians have not developed is anything like French cheese but I think that has as much to do with the climate as anything.
One of the techniques that we learned about in Peru has turned out to be very handy on the boat. Our friend Magdala was the first to show us the technique for making a strong coffee extract that can be kept in the fridge for several days and diluted with hot water to make a cup of coffee without getting all the coffee making gear dirty. After we tried it at Magdala and Gonzalo's home we had similar coffee served at small hotels all over the country.
When we are under way cleaning up is usually more of a hassle than making coffee and this technique eliminates the clean up step.
The Peruvians use special coffee makers to do this but we have found that our stainless steel French Press coffee maker works just fine. All you have to do is put 4-5 times as much coffee in the press coffee maker as you would normally use to make strong coffee. You fill the press with hot water that is just below the boiling point and stir the coffee so that it all gets suspended in the water. Wait a few minutes and press the grounds out of the very concentrated coffee extract that you have made. We usually pour it through a tea strainer to get out any bits of ground coffee that make it past the French Press.
When you want a cup of coffee just put a couple of table spoons of the concentrate in a cup and top it up with hot water. The concentrate stays good for several days in the fridge. We have been keeping in it a jar put plan to pick up a ketchup dispenser in Darwin and use that to easily dispense enough coffee. We quickly got good at estimating how much to put in the cup without the need for measuring. The consistency of this technique is as good as eyeballing the beans we put in the grinder.
Shawn also discovered that he could use this concentrate with some sugar and cold milk to make a very good imitation of a Starbuck's Frappachino (sp?). This has the advantage, in the middle of the night, of not having to heat up the kettle and then find a home of half a kettle of hot water when you are done. We are always worried that a kettle of hot water might become airborne in rough seas. As we get closer to the equator again a chilled coffee drink can frequently be more attractive that a hot cup of coffee.
What you get for a cup of coffee is indistinguishable from fresh brewed coffee and orders of magnitude better than instant coffee.. We grind Italian roast whole beans but I imagine this technique would work with whatever kind of coffee you prefer.