MicroTransat

[AYRSwebadmin]

AYRS has received the following letter, which I'm posting here and inviting the sender to join the forum. Comments are welcome.
Admin
______________________________________________________________________
Your advice about a crazy idea.

I'm sending this email, as owing to a mistake on my part, I was planning to come to the London Area
meeting on Saturday to seek advice about a project I’d like to investigate. As it’s on Sunday
and I have a prior commitment I won’t be able to come along.

I’m contemplating making an entry in the Microtransat, autonomous division/ sailing vessel class.
http://www.microtransat.org

I first came across your society after being given a set of books by a former member of my Yacht Club.
The subject of the book is self-steering and I couldn’t help but investigate it’s origin as it is a most unusual book.
I particularly like this kind of work as I’m a Yachtmaster and interested in technology.

My purpose in approaching your society is to seek your opinion as to whether you consider the idea
of building a vessel (max length 4m) propelled by wind power only and to send it on a mission to traverse the Atlantic
completely autonomously is feasible.

The response I am hoping to get is along the lines of
a) You’re completely mad
or
b) That’s a most intriguing idea, let’s talk!

I anticipate that it will require the following:

• Custom:
  Hull(s),
  Mast(s),
  Rigging,
  Sail(s),
  Steering and Rig control,
  Power generation and management,
  Navigation, Communications and Collision avoidance systems (my area of interest as I’m an IT consultant)

There isn’t much I can think of that can be obtained off-the-shelf so it calls for some
innovative thinking from people who like a challenge and can come up with novel solutions.

There are a number of reasons why I am contemplating this project.
1) My granny taught me that ‘nothing is impossible if you put your mind to it’
2) No-one has succeeded so far, and quite a few have tried.
3) I want to do this before the French do!
oh yes, and my wife says I should follow my dream!

I hope that you might pass this email onto members of your society who may be interested
or at least willing to offer their feedback on this subject.

kind regards
Richard Walker
PS I work in Southwark but live in Bracknell.

[Robert Biegler]

My purpose in approaching your society is to seek your opinion as to whether you consider the idea
of building a vessel (max length 4m) propelled by wind power only and to send it on a mission to traverse the Atlantic completely autonomously is feasible.

I know it’s feasible for a moderately-sized team of professionals, because Saildrone (http://www.saildrone.com) went from California to Hawaii, and they report a total of 60000nm sailed so far. I have no idea whether technology has progressed to the point where a smaller team of amateurs, with a presumably far smaller budget, can achieve the same thing.

The response I am hoping to get is along the lines of
a) You’re completely mad
or
b) That’s a most intriguing idea, let’s talk!

How about c) are you mad enough to talk to me?
It occurred to me a while ago that a sailing tethered airship (an aerostat) would make a very nice ROV for offshore research. Stephane Rousson has put this into practice: http://proafile.com/multihull-boats/art ... ed-airship. I have two designs for paravanes that I think would be more reliable than the Costes design that Rousseau uses, but I don’t have comparative empirical data. I think Bernard Smith’s variation on the scheme, with a wing stuck on the belly of the aerostat, would be stable in altitude at least when analysing the static case. Even for that, though, I know just enough maths to realise that I can’t work out a closed form equation describing the feedback. I might have to take the brute force and ignorance approach and write a programme to model it, but doing that for a dynamic model is well beyond me. and I have an idea for another design that would need less modification of the aerostat, thus cutting down costs.

I did look into buying a small aerostat, with a payload of about 1kg, to test the platform with plain old radio control, but gave up when I found out how much the helium would cost. And when I searched for hydrogen, I only found stuff on hybrid cars, not on hydrogen suppliers.

If you were interested in that approach, there would be quite a lot of up front development. I doubt it could be done for this year, and I estimate costs in the range from £5000 to £20000. Control systems would come on top of that. My plan was to contact a company that makes aerostats to carry radar systems, mostly for the military, and see whether they are interested in branching out into something rather more civilian.

One advantage of this configuration, which is what makes it so interesting for research, is that you can put your sensor package 50m above the surface. Radar reflectors, AIS receivers and senders, cameras and so on would not be obscured by waves. So that, at least, would help in implementing collision avoidance as you would at least have a clear view.

Also, I have absolutely nothing to offer on the robotics side.

Regards

Robert Biegler

[Fredthecharlie]

Microtransat some thoughts from the Thorpe Meeting
This subject was discussed at the meeting, but better preparation by providing delegates with the rules I think would have produced more ideas.
It was generally considered not to be a one man project because of the wide range of skills needed to complete the design, construction, testing and getting to the start line in a reasonable time, however as an arm chair exercise offering plenty of scope for thought and maybe searching for a like minded team and some sponsorship (maybe a Howard Fund application).
Last years competition seems to have lost competitors due to lack of communication; the rules requiring regular updates of position, at least one competitor was wrecked shortly after being released and another was caught by a fishing boat.
Reasons for communication failure include lack of power, poor aerials and electronic failure which could be due to mechanical or electrolytic damage.
Power needs to be generated and stored for when generation is reduced by prevailing conditions; PV only works during daylight and wind or movement systems when there is wind or waves.
One member of the audience suggested an all metal monohull including the sail, with a deep ballast keel on the grounds that it would withstand the prevailing conditions in the Atlantic and survive. Would it mask radio signals?
Generating electricity was discussed, PV cells, wind generation and using electrolysis (would the anode erode or the cathode foul?) were mentioned and since the meeting some form of pendulum mechanism comes to mind.
Propulsion using the wind was discussed and self tending wingsails mentioned, like most sailing rigs tacking to windward would make the algorithm for navigation more difficult but a rotor (windmill) rig would simplify things . More information on both these subjects can be found on an AYRS members personal web site www.sailwings.net
Keeping the Electronics dry absolutely essential as salt water corrodes and will cause short circuits so sealing of access hatches is essential as is sealing exposed wire where connections are made, some form of flexible diaphragm might protect sealed compartments from pressure fluctuations that might draw water in.
I wondered if a trimaran with a water filled ballast keel to allow recovery from knockdown using several wind mills to generate electricity and others to provide propulsion might be an option; several small ones keeping the centre of effort lower to reduce capsizing forces; or if the rules permit all to generate electricity and surplus electricity to drive propellers.
FCB

[Robert Biegler]

I wondered if a trimaran with a water filled ballast keel to allow recovery from knockdown

Why water ballast? For a given weight, lead would give you a lower centre of gravity. The advantage of water ballast is the ability to dump it or take in more. That seems an unnecessary complication while underway, and the boats are small enough that it shouldn't be an issue for transport. Even if roof-topping, being able to take the keel off and keep it inside the car would seem an adequate solution.

[Fredthecharlie]

My thought was that it would not increase the displacement but would provide a righting moment when the ballast bulb came out of the water, ie at about 80 degrees heel, it would increase imersed surface area however.
F

[Robert Biegler]

It would increase displacement, though. It doesn't matter to displacement whether you carry the weight in the form of water or something else. If you start thinking of a hull, then mentally add a water-filled keel, you don't need to make other alterations to the hull, and that can give the impression that you don't add displacement. But if you imagine adding a keel of the same shape and weight, filled with a small volume of lead and a larger volume of air, the lead feels more like added weight, yet the effect on displacement is the same. Only, you can get the weight lower down, and you have more freedom to distribute that displacement as you like, because you don't need much volume low down.

[Fredthecharlie]

Thank you for your interpretation, I agree that the boat mass will be increased but hopefully its weight carrying ability shouldn't be affected; I think that having considered your thoughts a high density bulb and an enlarged volume of the immersed hull might be better it should certainly produce a smoother stability curve although my water ballast might produce a hump giving a manned boat a better chance of recovering
FCB

[mikehoward]

Yes, I think you might be classed as mad BUT what an intriguing idea! The members of AYRS may well be classed as 'amateurs' but within the Society we hold a wealth of knowledge gained during our years of gainful employment. More importantly, most of this knowledge has been accumulated during the practical application of our chosen professions.

I am a retired Professional Design Engineer. During my career I have helped develop projects ranging from a Helideck for an Oil Production Platform to sophisticated equipment for the remediation of hydrocarbon contaminated products within an Oil Refinery setting. I have also a wealth of knowledge about marine equipment, composite materials and adapting standard equipment for bespoke operations.

SO - COUNT ME IN!

Initially, we need a meeting of all interested parties to draw up a Design Specification based on the current or projected Rules of the Microtransat Competition.

Mike Howard

[AlexQ23]

I think that if you think to build a metal hull it's mainly to increase the impact resistance, isn't it? For you information there is a coating available called Line-X that can bring any object almost unbreakable. And this is not propaganda! It works for real. And there is some representative in UK. Try to found the video and how they treat an egg...It could be useful for your project.

[mikehoward]

Richard Walker, the originator of this blog, and myself, Mike Howard, have decided to mount a challenge in 2018.

Initially we are going to undertake a Feasibility Study in order to establish the design parameters for our vessel and its equipment.
I will be the Project Manager. I have already had brief discussions with several members in order to form a project team of 'experts' in the various fields outlined in Richard's original letter to the Society. Fellow members of the Society are welcome to participate by contacting me via this blog or by telephone or e-mail.

Once I have completed my 'hit list' of subjects worthy of investigation I will e-mail it to all interested parties. It will not appear in this blog as it is too public!

We hope to apply for a grant from the Howard Fund in the foreseeable future.

This is a splendid opportunity for us all to pool our resources and achieve the goal of being the first organisation to sail an autonomous vessel across the Atlantic Ocean.

Mike Howard.

[Robert Biegler]

If the sailing airship is one of the options you will consider, email me.

[AlexQ23]

Good decision! If I could help I will be more than happy to joint the team. Suggestion: when you get all size and dimension of the frame, why not propose to members a kind of design contest as a first draft or so? And after that you can decide where to go?

[mikehoward]

Hello Robert,

I do not envisage attempting to be too radical in our approach to designing a Microtransat Challenger, but I appreciate your response and offer. If you wish to see the initial brief I would be happy to send you a copy in due course. I am sure you experience would add greatly to our knowledge base.

Hello Alex,
Thank you for your offer to participate. I want to form a solid Project Team with as much diversity in the relevant areas under investigation as possible. I do not believe there is anything magical about designing and building a Microtransat Challenger other than paying minute attention to every aspect of the vessel's hull and equipment. In my opinion, previous challengers may well have been well equipped to perform autonomously only to be let down by the lack of forethought in preparing the hull and its appendages for the ravages of the open ocean.

Interested parties wishing to receive a copy of the Feasibility Study brief should contact me directly by e-mail at ecotraction@aol.com.

Mike Howard

[fishwics]

See also announcement of RIN meeting on autonomous boats here http://www.ayrs.org/phpbb/viewtopic.php ... 2496#p2666

[John Perry]

I attended the AYRS meeting at Thorpe (Surrey UK) on Saturday and at this meeting Richard Walker gave an excellent presentation of the team's approach to meeting this challenge - they have definitely put a lot of thought into this and should very soon be ready to start basic testing of prototypes, albeit without the full systems for autonomy on board. The program seems ambitious for the proposed time scale but they have assembled a well organised team with a lot of relevant expertise.

Whenever I hear of something like this I cannot help thinking about how I might go about such a project, even though I have no intention to actually implement any ideas that pass through my mind - I am already busy with dinghy cruising, our new rowing boat and other boating matters.

So, purely as a 'coffee time' thought experiment, I was wondering what would be the simplest possible craft to meet this challenge - by this I mean the design with the fewest moving parts, the fewest actuators and the simplest software requirements. It might not be the best solution and would certainly not be the fastest craft one could envisage, just the simplest craft to do the job. Here is one suggestion, I would be interested to hear what others think about it and particularly to see if others can think of an even simpler solution.

My thought was a basic monohull with a fixed skeg (not a turning rudder) and a fixed wing sail set for a downwind course, i.e. a wingsail rigidly attached to the hull, no sheeting adjustment. The skeg would have a well raked leading edge to minimise the risk of entanglement with discarded fishing gear or the like and the skeg would be large enough that the craft sails on a downwind course without being steered in any way. There would be a cavity at the top of the wingsail and means to pump seawater in or out of this cavity. When the cavity is empty the craft floats with the wing more or less upright and the craft is ballasted so as to then be self righting. When the cavity is filled the craft capsizes to at least 90degrees and the wing goes at least partly into the water whereupon it offers considerable hydrodynamic drag so that the craft moves only slowly downwind. Solar cells would provide the pumping power and would need to be positioned for generation with the craft capsized or not capsized. Remember that the course is such that there is a favourable ocean current and most of the time a favourable wind direction, but certainly not always a favourable wind direction. Every few hours an on-board microprocessor interfaced to a GPS sensor detects whether the craft is making Velocity Made Good (VMG) towards the targeted destination. If there is positive VMG the craft continues briskly on its course. If there is negative VMG the pumping system is used to capsize the craft and it then moves only slowly downwind until the time comes for the next VMG check. Between VMG checks the only electrical equipment energised would be a timing device that requires minimal power.

A study of the winds and ocean currents would be needed to determine whether this approach would work. If the craft overshoots the target it would have to wait for an abnormal wind direction to get back and maybe the current could have taken it too far from the target in the meantime so that the craft is either wrecked on a shoreline or unable to get back before the wind changes again? Well, maybe, maybe not, I have no idea. Maybe a steerable rudder would be a necessary addition? A steerable rudder adjusted only at the time of each gps check would allow cross wind courses as well as direct downwind courses. That should greatly improve the chances of hitting the target first time while still allowing the simplicity of a fixed wing sail and avoiding many of the complications of a 'proper' sailing boat.

Any more ideas?

[John Perry]

The Saildrone people now seem to have a whole fleet of autonomous model yachts roaming the oceans. Here are a couple of links:

http://saildrone.com/
https://newatlas.com/saildrones-csiro/53117/ - this one also has a mention of the clever 'Waveglyder' wave powered autonomous vessel.
John

[mikehoward]

Well, John,it's nice to see that Richard provoked at least one member to 'think outside the box'. I'm a project team member and I can assure you that we have explored all of the conventional and a few of the unconventional avenues to arrive at our chosen hull form and sail configuration. In fact we spent three months completing a ninety page Feasibility Study before arriving at our outline specification.

Two major factors became very apparent. The need for reliable and long lasting electrical power and the effect that has on the final displacement of the craft. To minimise the weight of an external ballast keel we have opted for a lightly ballasted narrow centre hull supported by outrigger floats. This combination provides self righting with adequate form stability under normal sailing conditions. The craft is propelled by a rigid wing sail controlled by a rear mounted trim tab. The wing sail is fully buoyant and helps self righting in the case of a knock down or total inversion.

If the wind should prove unfavourable in direction, then the craft will tack into the wind. There will be no loss of speed under these conditions. The wing sail is capable of reducing its angle of attack and therefore its power as the wind increases in strength. In the event the wind exceeds the speed at which the craft can perform, then the wing sail is feathered, producing no power.

We had looked at a rig which could be lowered during storm conditions. It was quickly ruled out due to the power consumption necessary to raise and lower the rig. Your water pump would consume even more power and therefore it would just not be viable.

Your idea of the craft self steering is an option we intend to employ. The hull and rig will be balanced, allowing the craft to sail in a straight line without the aid of the rudder. The latter will only be deployed to change course. This methodology will also mean that the GPS/Navigation system can also be shut down for long periods. The saving in electric al power will be enormous. This, we believe, is were previous challengers failed to grasp the drain on batteries by constantly updating GPS positioning and course changing for little advantage. The Atlantic Ocean is vast. It matters little which course the craft takes provided in the last few hundred miles it can be coaxed into the finishing circle. It is this final 'run for the line' which will consume the most power.

Thank you John for your comments. I hope other members will throw in their 'two pennies worth'. There is always room to change our minds if someone comes up with a more convincing argument. After all, this is an AYRS sponsored project!

[John Perry]

Hi Mike
Best wishes for your project, its good to hear that you have thought everything out really thouroghly.

Just a quick comment on your comment that a water pump would just not be viable because of its power consumption. A very quick google search turned up this small pump, but there may well be other pumps that would be equally suitable, or more suitable.
https://www.anself.com/p-h16867.html

This little pump pumps 240litres per hour to a head of a little under 3m with a power consumption of 4.8W at 12V, ie. 400mA. It has a brushless motor (good). No life expectancy is given for this particular pump but a life in excess of 30,000hrs is claimed for a similar pump from the same supplier. So, for the sake of argument (not that two AYRS members would ever argue of course!) suppose the pump is required to pump 2 litres of water on average twice every 24hrs, (no idea, but you have to start somewhere). That's a time averaged current of 400*2*2/(240*24) = 2.8mA at 12V (34mW). I have a 5W nominal output solar cell that measures about 200mm x 170mm. Suppose the actual output averaged over 24 hours to be say 5% of claimed nominal output (the sun is not always shining, the orientation is often far from ideal etc.) the pump would require only a fraction of the output of that solar cell. Indeed, on that basis a simple calculation would suggest that a solar panel of about 7cm square would be sufficient. Of course you would need a battery and there would be some losses in the charging circuit and energy storage and you would also need to briefly energise a gps receiver and a microprocessor circuit every few hours, but even so the power requirements of the whole system would appear to be well within the likely output of an array of solar cells that could be mounted all over a hull of perhaps 2m in length.

[mikehoward]

Hello John,

I take your point with regards the pump. Yes, it seems very economical, durable, etc.
However, I am not prepared to divulge our strategy on the electrical power consumption/battery capacity/solar charging system here on an open forum.
If you would like to know more please e-mail me and I will be happy to explain our philosophy.

[John Perry]

Hi Mike, I expect that the AYRS membership would be interested to hear more about your design and your progress through this Forum and/or through AYRS publications so I hope that at some stage you will feel able to tell us more.

[John Perry]

A nice one at this link: http://www.bbc.co.uk/news/uk-scotland-n ... d-43838985
Doing quite well considering!
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[Dikshavarma]

The Microtransat Challenge is a competition to design and build an autonomous sailboat under 4 meters in length, which is capable of crossing the Atlantic Ocean without human interaction.

The challenge was originally conceived in 2005 by Mark Neal of Aberystwyth University and Yves Briere of ISAE. The first attempt was made on September 11, 2010, by Pinta from Aberystwyth University.

The challenge requires entries to use one of two predefined sets of end points. The first is to sail between a start line off the coast of Great Britain and a finish between the Bahamas and Florida, whilst the second is from a start line off the east coast of North America and a finish line on the west coast of Ireland.