Sail Drone further thoughts

In my original post on the sail drone, I expressed some pessimism that the thing would work.  In the meantime, the saildrone people put up some more information about their project and their designers.  Seems like they have enough experience to make the sail drone work.  One of the interesting things about the ocean is that the bigger the thing floating on it is, the more vulnerable it is to the forces of storms.  Small things like plastic bottles or coconuts can cross oceans with impunity.  So as long as a drone is small enough, it is probably impervious to damage. 
Still some problems remain for any autonomous drone.  The main one would seem to be collisions with ships and land masses.  Autonomy is one thing, avoiding collisions is another and adds complexity to the design.  The other problem with anything floating on water and containing electronic gear is water proofing.  As anyone who has ever bough a waterproof anything knows, waterproof is an optimistic term.  Water seems to be able to outwit almost any sealing technology so far invented.  Perhaps the most reliable technology is still the cork.  But we will see. I am keeping my eye on the sail drone website.

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Sail Powered Wheelbarrow

Seems like at one time or another, humans have tried putting sails on just about everything including, apparently, wheelbarrows.  The online Low Tech Magazine has a cool article on just such technology.
Apparently some of the sails were quite sophisticated, not just pieces of cloth, but battened junk rigs with control lines running back to the handles of the wheelbarrow.  This allowed the wheelbarrows to sail at an angle to the wind. 

 

The Chinese wheelbarrow differed from the European wheelbarrow not only in the size of the wheel, bigger, but also in its placement.  The load was balanced on the axle of the wheel which meant that on a level surface, the barrow driver only had to overcome friction.  The total weight of the cargo was being carried by the wheel. On a European barrow, the kind that is still being sold here in stores, the weight is centered between the axle of the wheel and the handles, which forces the barrow driver to carry half the weight, limiting the use of the barrow to short trips.

In any case, check out this and other articles in low tech mag.

Which reminds me, every once in a while, you will see articles on wheelbarrow boats in the small boat magazines.

Unfortunately, the wheel is usually on one end of the boat and is small, which limits its use to short distances. With a larger wheel placed in a centerboard trunk, the boat could be transported a good distance.  Of course we are now talking integral boat trailer, something which probably doesnt work as well as a conventional boat trailer and results in a boat which doesnt sail as well as a boat without an integral trailer.  Perhaps I should just quit thinking about this concept.  This sort of one thing does many things poorly design is something best left to the military procurement people.

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Deck Hardware and sail report

July 20, 2015

Sorry for the lack of updates.  But, I wanted to go sailing this summer and decided to put the computer on hold in exchange for a full focus on finishing the boat.

Deck hardware was installed with backing blocks, and polysulphide sealant.  It is amazing how many little screws, washers, lock washers, bolts, and nuts are needed to install the cleats and blocks.  This necessitated no fewer than 5 trips to my local hardware store that has a very good selection of stainless steel hardware (amazingly out of $10 lockwashers).  The only tricky part was the installation of the centerboard downhaul and uphaul, as this was a new type of system I needed to learn as I went along.  In practice, it works well, but necessitated shaving down the aft part of the floorboards that serve as a platform up front so that the lines would run free.

I also needed to move the boat onto the trailer, which meant the 18 workskiff needed to come off.  Using levers and jacks, I was able to lift the 1000lb clamming skiff off the trailer and then slide the Core Sound 17 onto the trailer from the building form using old rugs to protect the finish.  

The CS17 fits perfectly.  

I still need to add the self-bailer, and the docking hardware, and oarlocks, but it was time to get out on the water and see how long it would take to rig and launch.  

30 minutes to step masts and rig.  could be 15 without mistakes. 

As you can see from the photo above, there was very little wind, but the boat moved along even with ghosting conditions.  

photos of the launch. 

https://www.flickr.com/photos/41024536@N02/sets/72157655720562508

July, 21,2015

Went out to Hopkinton State Park.  It was much better with winds 5-12kts.  The boat sails beautifully, and points very well.  I was very pleased with how easy the boat is to control and how well it responds to gusts.  I felt in control at all times throughout.  

Sorry, no photos, I had my hands full.  

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Last big sail of the season

Hindsight being 20/20.  I am so glad I chose this boat as my most recent build.  It sails wonderfully with the changes described before.  I really like the mainsheet on the standup rotating cams. Much simpler.

The mizzen sheet works well as is.

I went out on Narragansett Bay for a 3 hour sail down to Bristol and back from East Providence.  Taking the boat out on a spur of the moment, and beating upwind for a couple of hours before a run home is awesome.

The only issue with sailing these waters is waiting to get space at the ramp.  Almost ran out of gas running in circles waiting my turn.  And, the number of uneducated power boaters putting up huge wakes in narrow channels.

Just off E. Providence

Providence, RI off the stern

Prudence Island in the fore ground.

The forecast is for sub freezing weather, and a change in the weather pattern.  So, this will probably be the last "real" sail of the season.  Motor is off and drained for storage.  We can still hit the lakes, and just paddle back.

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Sail Drone

While driving to work a few days back I noticed some people hoisting a small red airplane looking thing from a trailer.  As the lettering on the wing of the thing indicated, it was a saildrone. When I got home I went to their website http://saildrone.com. There wasnt anything there except a home page, but they have since fleshed it out some.  Anyway, some pictures of the saildrone.

 Here they are unloading the saildrone from its trailer.  At a distance it looks like the tail is at right angles to the main wing but thats an optical illusion.  The horizontal spar that the tail is mounted on is actually at an angle to the horizontal plane and that creates the illusion.

 Thats a lot of crane to unload this small a thing, but the crane was already in place to take the Swedish Americas cup boat in and out of the water.  OK so some overkill is justified.

 The head on view shows the arrangement of the verticals.

And here it is sitting in the water.  Even with a little wind blowing, it heeled way over.  More ballast, I would think.  I also cant picture something this small operating autonomously in the ocean with breaking waves.  Snap that thing in pieces in no time and bend the heck out of any metal.  But I might be wrong.

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Sail Speed Records

New speed records for sail powered water craft are being set constantly. The latest by the Vestas sailrocket is 65.45 knots.  Of course these are records set under ideal conditions.  One should not expect cargo carrying sail boats to reach these kinds of speeds.  Still, regardless of limitations these records are impressive and raise the question, what makes these speeds possible and why werent they achieved in the past? In other words, what has changed?
I suspect the answer to the question is multifaceted.  Perhaps the biggest impediment to new boat designs was tradition.  It took a while to apply airplane technology to sail design.  It also took a while to bring the weight of a sailing craft down enough so a sail could generate enough power to make the sailing craft rise on a hydrofoil.  Speed in a watercraft seems to be limited by friction between the craft and the water and minimizing that makes new records possible.
But in the past, new, faster sail boats evolved from working craft that had to operate under all conditions and not just special race course conditions.  One thing that is apparent from watching the videos of sail records being set is that the wind seems to be off shore with the craft racing alongshore, thereby avoiding waves. 
And there are any number of other things that a useful work boat has to be able to do that a racing craft cannot do.  Still, new ideas are always welcome.  I am looking forward to seeing recreational versions of these craft.  Who knows, perhaps a skin on frame model that does 20 knots would be a fun experiment.  Planing hull, no hydrofoils. 
The little experimenting that I have done with putting sails on skin on frame kayaks has taught me that the inherent flexibility of skin on frame hull limits how much sail one can carry.  The faster the boat is expected to go, the stiffer it needs to be, or in any case, stiffer than a boat that travels at 4 knots.

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Sail report Buzzards Bay day 2

August 21

Took the boat back to Wareham.  It was a glorious day with winds 10-15 kts and crystal clear skies.

We sailed out to the middle of Buzzards Bay and then went back to the sand spit for lunch.

I cant say enough of how well this boat sails and the ease of launch and retrieval.

Lunch on the sand spit.  It doesnt get any better than this.

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