Thursday, December 4, 2014

Ensenada and Turtle Bay

Having spent a wonderful 6 weeks in San Diego, catching up with old friends, meeting new friends, completing most of my long term boat projects and enjoying the swimming pool and hot tub it was time for us to head south to Mexico before our roots take hold. 


Following the completion of some last minute chores, checking out of the US and saying our goodbyes we cast off our lines from the dock and made our way over to an anchorage that would enable us to easily slip out of San Diego in the middle of the night so we would arrive in Ensenada in the day light. Once the anchor was secure we lit the BBQ, slapped on a couple of steaks and cracked open some beers. Even though it is only 1/2 a mile from the dock it's nice to be back on the anchor. 


We had agreed to buddy boat with Mike and Jan on Rapture (www.svrapture40.com) and we both pulled up the hook at around 2:30am and motored out of the channel in darkness. Once out we raised the sails and were making a great 7.5 knots until the wind died. On came the motor. The sun rose and with it the wind picked up so out came the sails again and we had one of the best days sailing we have had for a long time. Beam reach and flat seas so we were making 8.5knots at times. Pure joy. 


We arrived in Ensenada with the wind blowing 20-25knots, weaved our way through the myriad of crab and lobster pots on the approaches to the marina. I swear these are put there as some sort of obstacle course: most have floats too small for the pot and are submerged most of the time and then they paint them dark blue or black, not exactly the most obtrusive things. 


We entered the marina squeezed into a slip that was 5 feet too small and went to check in at the office.  We were too late to do the formal clearance into customs and immigration so that would have to wait until tomorrow so we went and checked out the marina facilities: two outdoor pools, one indoor heated pool and three hot tubs, one of which is outdoors. Also it has a steam room, gym and sauna along with a bar and restaurant. Coral Marina is not the cheapest place to stay in Ensenada, especially short term, where they fleece you of everything, but a month's deal is about half the price of a slip in San Diego with better facilities. True, the marina is out of town but only a $0.70, 5 min bus ride away and is quieter than the downtown marinas. 


The formal customs clearance was simple, thanks to the service Juan gave is in completing the paperwork. We stood around, signed the various documents and handed over cash. There was a slight hiccup in the proceedings when they requested my registration papers for the dinghy which we don't have, so with a quick trip back to the boat I rustled up a "copy" of the bill of sale. All good in the end. 


Over the next few days we checked out the town, sampled various Mexican foods and started to practice our spanish, which definitely needs a lot of work. We purchased a Mexican SIM card with data plan and of course spent lots of time in the pool. 
Marina Coral and Hotel


We are pleasantly surprised by the quality of the supermarkets. Most foodstuffs can be purchased here and the prices are slightly lower than in the US. Naturally the selection is not as great but it was a lot better than I had expected. 


Katya seems to be growing fast and seems to be heading to the teenager years a bit too fast for my liking! She is doing well with her homeschooling and continues to draw and paint. There does however seem to be a dearth of people her own age to spend time with. Hopefully that will change later. 


James and Sara on SV Tatau came into town and we caught up with them along with Richard and Gerri and Jake and Danielle on SV 'Ohana. Always good to see familiar faces and swap stories. 


We decided to stay to watch the start of the famous Baja 1000 off-road race which starts in Ensenada and goes 1300 miles to La Paz. This endurance race has been run for 47 years and is quite the sporting event. Some of the vehicles were staying a the marina hotel so we got to see the cars and trucks close up and chat to the teams. These vehicles are quite amazing, not just your average 4WD but with 800 hp engines and cost many hundreds of thousands. I watched the start of the race at a vantage point where the vehicles got some airtime. They sounded amazing when they went past. 






After much more lounging in the hot tub and pool we decide that it was time to make tracks south so we planned to leave on Monday the 24th. The night before we went and said our good byes to James and Sara on SV Tatau and Michael on SV Comanche came over for dinner. We woke the next morning but Jude had acquired her first cold in two years and felt awful, so we decided to delay our departure another day and give Jude a chance to recover a little bit. 


So the morning of the 25th came and we slipped our lines and headed south to yet warmer waters of the Sea of Cortez, a journey that should take us about 10-14 days. 


Since we left Washington state, ever day we journey south, I think of how wonderful it was up there and how hard it is to get back in a boat. It's known as a bash. So the further we go south the longer the bash would be to head back. We could always sail back via Hawaii which is a very long passage. Some people do this journey and either sell their boat in Mexico, carry on south, west or east or put it on a truck back home so as to avoid "the bash". 


The wind of course died to less than 10 knots as soon as we put the sails up. Not sure what the sailors equivalent to Murphy's law is but there must be one. We motored and then desperate to sail as much of the way as possible I decided it was time for the symmetrical spinnaker to go up. It was the end of last season that we las had it up because it's a bit of a palaver to set up short handed. We got it up and Murphy stuck again after 45 mins and the winds shifted to the beam so we took it down and motored again until the winds picked up strength and we could sail at last but that was a few hours away. 


We sailed the rest of the way to Turtle bay with winds on the beam mostly but with some from behind and some in front. The seas thankfully were pretty small and therefore not rolly. Always welcome especially on your first couple of nights after being on the dock for a while. 
Mahi Mahi


We enjoyed looking at the stars at night, seeing them rise in the east and disappear on the west horizon. We sat and watched a meteor shower, one of which was particularly spectacular, made an unusually slow entry lasting five or six seconds and then disappearing after a bright and large explosion of white light. Katya and I watched dolphins weave their path across the bow in the darkness leaving an amazing line of bright phosphorescence. It did take a bit of persuasion to get her to come and look as  Katya has been glued to the Twilight series of books finishing the first two books in 4 days.  One more book to go I believe. 


The first leg of our journey was 284 nautical miles and we covered it in 44 hours, 25 of which were motoring. Just before we entered Turtle bay the winds picked up from nothing to 25knots on the beam with gust to just under 40 knots. We sailed into the bay at 4:30am and were pleased to drop the anchor and get some un interrupted sleep. 


We awoke to a bright and warm sunny day and to a strange looking landscape. It's about as arid as it could possibly get. Not a tree in sight. Martian looking place. We took our dinghy to shore to check out the local town with its dusty dirt streets and ram shackled houses and shops. We tried to find some local food but everything was shut. 







Sailing off the Rhumb line


Whenever I plot our course on the chart to our next destination I always plot the most direct route which I perceive to be the quickest. Those of us who sail know that firstly you cannot always sail a direct route as the winds might be dead ahead, on the nose as I like to say, in which case you have to decide if you want to sail at 45 degrees to the most direct route and beat your way to your destination or motor. That is quite a simple decision: do I or don't I want to sail. But it gets more complicated if you want to sail but the sailing course is off the rhumb line particularly when you are not on a close hauled course. 


A sailing boat is more efficient in terms of boat speed or velocity made good (VMG) on different angles to the wind and these efficiencies are plotted in what are known as polar diagrams. Most manufacturers publish these polar diagrams. Typically a boat is more efficient when the wind angle is on or forward of the beam and least efficient when sailing dead down wind (wind angle 180 degrees from the bow) and a progression of efficiency between the two angles of approx 45 degrees and 180 degrees.  For instance this means that if I have the wind behind me at 180 degrees I will sail faster if I change course so that the wind angle moves forward, I.e. an angle less than 180 degrees and higher than 45 degrees. But this means that I am heading off course and will have to sail a longer course in terms of miles. So the question is if I sail a longer course but a faster one will I get there quicker? Maths and physics were never my strong subjects at school but at least they had some everyday practical applications I could relate to, unlike chemistry which completely confused me (easily done some people say).  So I got to thinking how can I work out the answer to the question : if I sail faster but longer will the journey be quicker. 


I remember something about triangles, angles, and trigonometry but very little so I spent some time relearning things I had long since forgotten, or never remembered, in particular trigonometry. I wanted to be able to get the answer to the question quickly when sailing so I did not want pieces of paper and calculators rattling around the cockpit whenever the question pops up so I decided to write a spreadsheet to answer my questions, so next time when I am sailing downwind I could answer the question: is it better to change course off the rhumb line?  It actually turned out to be quite simple to create with only one trigonometry equation used to calculate the length of the sides of a triangle.

I won't bore you with the other calculations in the spreadsheet but I created a spreadsheet that enables me to enter my current rhumb line course distance, my current downwind sailing angle and enter a course adjustment in degrees and it will tell me how much longer the course will be. Now by entering the data from my boat's polar chart the spreadsheet automatically calculates the adjusted boat speed for original and adjusted wind angle of sailing and presents the projected time taken for both the original course and adjusted course. This means I can see if the revised course is more efficient. 


It is not a perfect piece of work by any means but it demonstrated to me that you don't have to pick up much additional boat speed to make a course change worthwhile and that, for my boat, I am better off sailing at about 140-155 degrees than 180 degrees for wind speeds of less than 15 knots. That is to say my velocity made good , VMG, to my destination is better than on a dead down wind course. 


Now theory is a wonderful thing. Create a pretty spreadsheet with numbers and colors and diagrams and it all looks great. Putting it into practice is a completely different thing. Firstly I have to make a conscious decision NOT to head in the direction I want to go. No matter how I try to justify the decision to alter the course it's a hard one especially on a course that is hundreds of miles long as if the "theory" does not work it could cost me hours or even days of extra time. The theory is all well and good if the parameters entered stay the same, which is rarely the case when you are dealing with nature. Wind and wind speeds are always changing and then you have to take I to account currents and effects of different land masses if there are any. So, I thought that I would test the theory on our latest passage from Ensenada to Turtle bay in Mexico, some 280 nautical miles.  On much of the journey, the winds were too light to sail, less than 6 knots, so it was not a perfect test run but when we were sailing downwind I made the difficult decision to alter course to gain speed and was pleasantly surprised how much time you can save by a few degrees in course change. I must admit that I could not bring myself to change course by 35 degrees, which the spreadsheet suggested was the optimum course change as I was rightly nervous about wind changes that would leave me many miles off course. I decided for a more conservative approach altering by about 15-20 degrees. I ended up sailing an extra 5 miles from the plotted course and believe I saved about 1 hour and 29 minutes. Next time might be a little more adventurous and try the 30 degree course change. 


There are a couple of additional benefits of altering course from dead downwind, those being that firstly you can sail more when winds are light. By altering course the apparent wind increases so for instance sailing 6 knots dead down wind for me is way too slow and I don't do it but alter course and it becomes possible. Secondly the quality of the ride is much improved. My boat hardens up and does not roll as much and the crew are happier as well. Sails do not flop about in lighter air. I don't have to use a pole, I knew that before but never wanted to sacrifice time in order to stop those effects. Now I know I actually benefit on the time front and spend less time motoring. 


One flaw to the spreadsheet is the polar diagram data, which predicts the boat speed based on wind speed and wind angle. I found that I could not match the manufacturers figures for speed at a given angle. This could be that I am not that great at sail trimming, or that my boat is laden to the gunnels or that I am not always using a spinnaker or sea conditions are not the same as the manufacturers test conditions, therefore I was always slower than the predicted speed. I have started to note down my boat speed for any given sailing angle. Over time I hope to have enough data to accurately predict boat speed. In the meantime I will downgrade the speed data in the polar chart. 


It's been a fun and rewarding g exercise and if any body is interested email me and I will send you the spreadsheet. If you are not keen on using a spreadsheet I have created this simple chart  that tells you what speed you must achieve for a given course change to achieve the same VMG as the original course and speed. Any additional speed will mean that your altered course will be quicker. 





3 comments:

  1. David's salivating over here so, yes, please email one to us!

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  2. Okay, please send one to me when you have a chance :-) One question though - I assume your chart plotter calculates VMG (if not, please disregard) so why can't you just use VMG? That is how I decide the best angle of sail. Or am I just being too simple minded (happens a lot to me).

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  3. As far as your comment about the VMG on the chart plotter is concerned. You are right in saying you could just alter your course until you achieve the best VMG and that does work but on my chart plotter it only calculates the VMG on the tack/gybe you are on to the next waypoint at the time and does not calculate the total VMG based on both tacks/gybe. And therefore you would have to sail both angels first, record the VMG for each calculate and the total VMG based on the distance of both sailing angles. (I have a Garmin 4212) your chart plotter might be more intelligent and be able to calculate and predict the VMG for both tacks/gybes to the next waypoint but not sure how it could unless it bases it on a projected speed for the next tack/gybe. What do you think?

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