GPS Guided Trans-Atlantic Robot Boat

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Blog6 Analysis Page ( from Snoopy's "Blog6" page )
- the Atlantic Attempt in October 2016 until now.

"I always wanted to be an engineer, and now I are one !"

Created 1045 Z/GMT/UT (1145 BST) Thursday 6th July 2017 UK time
( Old material moved from Blog6 to make that smaller )

See Snoopy's October 2016 Atlantic Attempt, Snoopy, or the Design of Snoopy Sloop page for background.
Each "blog" page describes detailed work preparing for the next Atlantic Attempt. i.e. covering a period in the region of a year: less if more than one attempt is made. The Blog pages were started after the first 2012 Attempt, where Snoopy's boat was lost. All later attempts were with the same boat, sometimes after major repairs. The blogs provide online "Engineering Notebooks", providing a day-by-day account of repairs, changes, and testing: mostly testing.

Origin of wheels for Snoopy's trolley click here for more on the Horse who snatched Snoopy These blog pages are mostly about numerous repairs to the boat, results from "BRAY LAKE TEsts", or 24/7 reliability testing on Bray Lake. i.s. Snoopy sailing back and forth over a 24/7 waypoint in "Snoopy Corner". This is typically for several weeks, in all weather, including gale force winds. Sometimes, a few things happened which resulted in amusing pictures or stories, such as countering human-intervention, or testing the wheels for Snoopy's trolly. Click on the pictures either side for larger versions, or visit earlier blogs above. BlogX, the "blog of experiments", shows ideas and products, some of which may appear in future boats.

Analysis of the 2016 Attempt, before Boat 11 is prepared and tested on Bray Lake ...

We start with analysis of what we think went wrong with the boat on the October 2016 Attempt. It makes sense to get as much information as possible from each attempt, before making the next boat. As it happens, Boat 11 has been "waiting in the wings" for years. We did not expect to keep getting Boat 10 back ! :-)

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Thursday 6th October: The Launch and first 24 hours of the Atlantic Attempt ...

You can read the full story in pictures and video on Snoopy's October 2016 Atlantic Attempt.

GPS Guided Trans-Atlantic Robot Boat GPS Guided Trans-Atlantic Robot Boat

Snoopy's drift In short: Snoopy made fast progress, but with a steering error to the right, that got worse, before his last SPOT report, just before he is assumed to have hit rocks on the east coast of Portland. Analysis of wind and tidal current indicates that he was probably then swept out to sea. The following information has been moved from that "October 2016 Attempt" page above.

Peter's KML map, based on SPOT data, etc. Last SPOT position was 1004 BST Friday 7th October. Google Earth will display RBAA16A.KML.

Snoopy's 2016 Trans-Atlantic Attempt

It should not be a problem, but it is certainly not what was expected. It seems that, through an "accident of good fortune", of wind and tide directions, and geometry, Snoopy managed to "cut the corner", skipping the "Channel" Waypoint, to make faster progress. It seems Snoopy may be steering to the right, probably due to the rudder not being exactly centered. He made little progress on Thursday night, because the wind was not strong enough to fight the eastward tide. Now Snoopy has the tide and wind behind him, until the tide turns eastward again at about 0800 BST Friday. Let us hope Snoopy does not get too close to Portland Bill - he's done that before ! :-)

Snoopy's 2016 Trans-Atlantic Attempt

Friday 7th October: Dick searches for Snoopy on Portland's east coast ...

Snoopy was last seen on his SPOT tracker at 1004 BST, heading towards Church Ope Cove. A sighting or photo would be good !

Email received from Dick at 1805 Friday, before he headed back home from Portland: Hi Robin, Well no luck I'm afraid. I've walked the very rocky shoreline from the car park north for about 2-3 miles and examined the shoreline south of the car park for about a mile. Pity we didn't get one more transmission just before he came a shore, or better still just after so a identify the spot... etc "

Everyone: no taking risks please. I'm sure Snoopy will turn up one day, and at least it means we can switch to his much lighter Boat 11, waiting in the wings for years ! :-)

Snoopy's 2016 Trans-Atlantic Attempt

Portland from the East, using Dick's AA16PATH.KML on Google Earth. Later Wind & Tide analysis shows Snoopy may have travelled south, to left, towards Portland Bill.

Snoopy's 2016 Trans-Atlantic Attempt

Cheyne House The rocky coastline is difficult to reach from land, to the south, as Dick discovered. You can use Dick's KML file with Google Earth, to explore the area, or google images such as "east portland coast". I found this one of Cheyne House, near Freshwater Bay, that looks a nice place to stay. Click on the image to enlarge it.

However, a search for Snoopy along that strip of coast, would be done much easier in a suitable boat in suitable weather and tide conditions. Remember that the "shambles" is a notoriously dangerous area of strong tidal currents. More importantly, you could be wasting your time: Robin's best bet is that Snoopy was carried out to sea. See the information below, on wind and tidal current.

Snoopy's 2016 Trans-Atlantic Attempt

What went wrong and why ? Steering errors to the right ? Rudder not exactly centred ?

Snoopy's 2016 Trans-Atlantic Attempt Google Earth analysis of Peter's KML file confirms that after launch, Snoopy was steering 17 degrees to the right, but by next morning, this was nearer to 90 degrees. The last autopilot software change was 15th February 2015, to add the "Weymouth" Waypoint. Details of software testing, including with Peter's software rig, are in Blog4. e.g. When east of "Weymouth", Snoopy should be aiming almost directly south for that waypoint, but this switches to "Prawle", to the South-West. This "Blog4" also includes detail about Snoopy's rudder servo linkage: look at the work in January 2015. That servo "lever arm" should be held by an allen screw, clamped tightly against a flat, filed onto the rudder shaft. The whole lot should have been fixed with Locktite, AFTER making sure the rudder is exactly centred, by testing on Bray Lake !

Snoopy's 18 February 2015 Bray Lake Test

No Bray Lake Tests of Boat 10 since before the 2015 Atlantic Attempt !!!

I was horrified to discover, after looking at Blog5, that Snoopy's boat had not been tested on Bray Lake since the lastAtlantic Attempt in March 2015 ! It's hardly surprising that the rudder may have been a bit off-centre ! Looking further back in time, in Blog4, shows weeks of 24/7 reliability testing on Bray Lake, in February and March 2015. Click on that picture to enlarge it. The last "Bray Lake Tests" were in February 2015, and show tendency to steer to the right. It seems it was never corrected !

My "Blog" pages are my "Engineering Notebooks", akin to what I was taught to use as a young engineering apprentice, working in a laboratory for the first time, in the early 1960s. The difference of doing it online is that lots of people can look over your shoulder and see where you made mistakes ! :-) white strip

Where is Snoopy now ? We need a visual sighting, or even a photo ! :-)

Snoopy's 2016 Trans-Atlantic Attempt Snoopy's 2016 Trans-Atlantic Attempt

France is only 100 nautical miles downwind ! :-)

While we wait for any really useful information, such as a visual sighting of Snoopy, we can speculate on where he might go in the days ahead....

The picture on the right is from Robin's old DRIFT model, originally used on GPS Bottles projects, years ago, and last used on the American Toy Boat page in March 2016. It needed the right tidal current and wind data plugged into it. e.g. tidal current maximums between 1.2 and 1.5 knots. e.g. Winds 15mph from North East rising to 25mph from East-South-East by Wednesday. Wind predictions are taken roughly from Ventusky This gives a rough guess on where Snoopy might reach by Wednesday 12th October, or earlier.

The white track is of a bottle, half submerged, drifting with the tide and surface water at about 3% of wind speed. The blue track is at 5% - something catching the wind a little. The green is 10% - perhaps Snoopy with sails up,but with rudder hard over, drifting in circles. Yellow and purple are 15% and 20% - sails up but with rudder central - running with the wind.

There are LOTS of assumptions here. e.g. that Snoopy managed to get free of rocks. e.g. that Snoopy drifts downwind, with his sails still up, and no steering by his autopilot, and the rudder to one side. We think they have broken by now anyway. If they were working at all, his path would be more westward. But speculation is no substitute for observations ! :-)

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What would we do differently next time ? ... Next year's Boat 11 ...

The following is taken directly from the Design page, where it has been for some time. Perhaps I should add "5) do Bray Lake Tests to check the rudder is central" ! :-)

There is a lot I would not change in next year's Boat. e.g. 1.2 metre long Marblehead hull with IOM #3 Storm sails; GPS-Only Autopilot, based on Picaxe computer and Globalsat BR355 GPS. I may experiment with new ideas, such as power switching, compass steering, and wind direction sensors - but they are only adopted after many months, or even years, of prototyping then thorough testing. However, I've added this section, so you don't miss important future changes, mostly based on the discovery of better products. In short they are: 1) Use of SPOT Trace, instead of a modified SPOT Messenger; 2) Use of the Picaxe 28X2 Computer, instead of the Picaxe 08M2: more memory and comes assembled; 3) Use of the Globalsat BR355-S2 GPS, including applying a firmware patch, and configuring it with Static Navigation off, and only $GPRMC sentences; 4) Fewer but better solar panels. You will see these products discussed in more detail, later on this "Design" page and linked pages. The pictures should help you find the relevant sections.

next year's boat

The story continues in Blog6 :-)

© 1991-2017 Robin Lovelock. Please credit if you use material from any of these pages. Thankyou.