GPS is worthless for actual boat speed through water. GPS speed is based on change of position over time, which includes current and windage.
On the other hand doppler measurement of passage through the water might be the best choice, but I know nothing about it. Google time!
Thanks for the idea Andrew.
Pete
Pete
Good Morning
I considered a log thrown over the side attached by a cord with knots in it such that the rate of passing of the knots would be a measure of boat speed thru the water.
But that is clearly far fetched, even in a Radical thread!
Can you get all the logic and control and storage batteries into a footy?
Thinking inside the box we have an absolute max of 1/2 cu foot to play with - I think we must allow a middle size rig - or perferably a self-regulating rig with roller reefing - an MacReef?
andrew
I read about a mag flow meter. They are used to calculate the volume of water flowing throught a pipe. Might make a good boat speedo.
I think we have more like 1/12th of a cubic foot. The entire box is 1/2 cubic foot! There are expensive but workable autopilot/GPS’s that are small enough to fit in a footy. The FBI, CIA and Homeland Security probably investigate people who buy them.
The big headache to me is programming something that can decide when to tack, and knows when it is sailing by the lee, etc. That means I have to know the approximate boom position as well as apparent and true wind and all that good stuff that you take for granted when you are in the boat.
The interesting thing would be to see how much gear can be jammed into a footy and still work. I had problems getting all my extra gear to work in one of my RC planes. I had a video camera and transmitter, the camera mounted on a tilt and pan that responded to head tracking gear on the ground. I added an LCD screen in the plane that could report airspeed, altitude and battery condition and that I could look at with the video camera. Basically, an instrument panel. Worked fine on the bench, never got the hatch closed in the field without something quitting.
One of the ongoing threads in the FPV (first person video) forum is about dealing with the rat’s nest of wiring we tend to wind up with.
Pete
This is a link to a very sophisticated 28 gram autopilot.
True it is designed for aircraft, but it can steer and report back to a ground station. What is needed in addition are sensors for boom position and speed through the water and actual compass heading of the boat. Direction through the water might be handy and also apparent wind. True wind can be calculated from apparent wind speed/direction vs GPS heading and speed.
The hardest part will be programing an intelligent controller for the boat. In other words, something that knows how to handle a boat and not try to sail directly into the wind and other stupid things.
The little chip sized computers used in robotics are probably large enough to make the sailing decisions.
Pete
Well, stone the crows*, even radicalism (apart from Pete) has been seemingly hiberrnating.
Pete - your energy is inspiring.
Not sure that being replaced by an electronic dead beetle is very motivating for the drivers. I have to tell you that for much of its life so far my Razor has definately been under some other control rather than mine, but I ascribed this to malign influences and the boat’s rejection of my control suggestions.
In the case of myself and three colleagues there has been frenzied, slightly radical, paddling under the surface while maintaining our outward appearance of normality. Can’t tell you about it now, but results may be visible soon in a pond near you.
Construction techniques are being pushed to, and beyond, the reasonable limits - thus finding where the actual limit lies.
ZBF has been christened , and now awaits only completion. I have found no micro-hydraulic supplies, and will therefore make my own. That leads to the thought of MBF ll with fully mission-adaptive hull using the same hydraulics and flexible and deformable skin.
I can see my Marblehead footy beckoning again!
My aircraft experience (and indeed obsession) still suggests that a fast footy needs to get right out of this cold, clammy liquid. I have therefore contemplated developing the savoniFooty to drive telescopic, powered caterpillar tracks. Slight development challenges are anticipated
andrew
None of the genus Corvidiae* (or stones) were harmed in the writing of this email
I have come to a decision to actually make something that can ease the sheet(s) in a gust.
I bought an embedded controller kit with breadboard to experiment with and I plan to get a robotic tilt sensor. The goal will be to write software that can intercept the servo pulse and measure it, then pass it through to the servo.
In the event that the boat heels more than say thirty degrees, the servo pulse is either lengthened or shortened (as needed to ease the sheet) until the angle of heel is thirty degrees. If the angle is less than thirty degrees the sheet is taken in to where the skipper has set the sail control.
Once I get that working and figure out how to measure boat speed I will have the controller play the sheet looking for an optimum setting. Two way telemetry might be fun at that point.
None of this seems difficult now, but fate and Murphy have a way of pointing out those little things that escape your consideration until the boat is in the water.
Anyway, it sounds like fun to tinker around with my computer and breadboard, and if I get something that looks like it will work I will make a board with sensors and embedded controller and see what happens.
I’d plan to enter the Atlantic crossing race, but by the time a footy at hull speed makes it across it will probably sink under the weight of the accumulated barnacles.
Pete
Pete,
Every silver lining is a black cloud in disguise - if you can get the barnacles to perform differential accretion it may be possible achieve steering or possibly even propulsion! Or you could make the boat hull of tin which they might not adhere to?
I have a computer for gust alleviation - its an analogue model and comes installed in every MacRig. I have never had to reboot (but Gary Sanderson has had to wind up his rubber band again!)
I just Know I shouldn’t ask in the radical arena, but how is your (conventional) footy progressing - I seem to remember it was awaiting a rig.
Given your ocean-spanning imagination have you considered a linear gossamer rig. There are spiders which fly oceanic distances at up to 35000 feet. A few of these hitched to the hull should help with propulsion.
andrew
Pete,
How come you are awake? Are you the token man at the helm while the Americas drowse, with their little faces twitching into smiles and their thumbs re-running the races where they blew NZ america’s cup yachts(full size) into the weeds.
If so all the election pre-ballyhoo must be aimed directly at you.
No wonder you have an aim is perfectly reasonable by comparison.
andrew
My last reply was at around ten o’clock AM New York time. I am at work, it is a holiday (President’s day, celebrating the birthdays of Washington and Lincoln) and things are slow here, so I have time to check the internet.
If I could get the barnacles aligned right they could definetly add to the propulsion. They are filter feeders with a little fan like scoop net. They would be perfect if there were some way to get them all to scoop to the rear, but there are always these rebels who take advantage of the forward motion to scoop the other way and get more filtering done each time.
Maybe I should tank train them with regular feedings of corn meal, all coming from the rear of the boat, then plunge them into the ocean before they figure out what I’ve done. I’d feel like I was treating them like galley slaves.
Anyway there would be no need for sails, but then it would not be a sail boat either!
My conventional footy is going to have to wait for the end of a trade show before I can get back to it, though I may get to work on the programming of the tilt sensor in the evenings.
It was built in a great hurry and I see all the things I want to do differently, but I will finish it just to have a boat. I ordered some very thin mylar and it should get here this week. Five micron or whatever. I have some lighter stuff at home. My thinest is used on indoor models and is thin enough to be sort of apple green/bluish like an oil slick on water. I think that may be too thin for a footy.
Pete
Pete, if this material you plan to use doesn’t stretch then it isn’t too light to use for Footy sails. If it stretches, and won’t hold an airfoil, then it is useless.
Hi Niel,
It’s mylar so it has no, or very little stretch, but I have it in thicknesses almost certainly lighter than most people have ever seen it. The lightest is blue green from refraction, just like the surface of a soap bubble. The thicker stuff is two microns and five microns. Way lighter than Saran Wrap or stuff like that, but moderately strong, as mylar tends to be.
I think the blue green stuff would make a great spinnaker for winds of 1/2 mph or so, but would probably blow out if the boat rocked.
If worst comes to worst I will look for something stronger. I have some double stick tape for tacking on reinforcements and I also have iron on films of the same stuff, but I am afraid of shrinking it unless I can stretch it drum tight while ironing.
Dunno where this is all going, but I am having fun.
I am spending the rest of the week setting up and working at the WRAM show (RC Planes mostly) at the White Plains County Center, so I will not be able to work on any of this until I get home and resettled into my routines again, though I will be on line in the evenings.
Pete
Is this radical enough for anybody?
Rod
I guess a chine barkentine is pretty radical, and I don’t think I’ve seen tumblehome at the bows before.
Pete
Rod,
This is great and really Radical - I can see we need a sort of oscar for the radical footy mob (I was going to say fraternity, but fervently hope that we will be blessed by female creativity tooooo)
The most radical feature of this design is that the gunports DO NOT FOLLOW THE SHEER LINE!
You are a bold innovator, sir, well deserved of the radical label
Pete - I think that view is from the bow, and it seems to me that the tumblehome runs out about an inch from the actual bow.
I can’t see the figurehead clearly, Rod - had you got a name or figure in mind?
Now, when can you have one sailing?
andrew
Rod,
A more careful study of your drawing shows that you have arranged the F&A sails to operate from the square sails (masts), and that you have also adopted bentinck booms.
As I have said before, not only radical but sensible too!
In the model flying fraternity there is the equivalent of a footy - called a Peanut model. This is basically a scale model with 13 inch wingspan. At this size (like a footy) it is VERY sensitive and challenging to fly. If the size had been say 16 inches wingspan the resulting planes would have been relatively easier to fly successfully.
Making Rod’s beauty as a footy will be a real challenge and masterpiece. Doing it about 20 inches or so in the hull would be enormously easier - but not a footy.
andrew
It (she?) is just a concept right now, as I haven’t decided upon a material to construct the hull. Both sides and the bow are to be made from one piece of material bent around and I have not decided what will have sufficient strength and flexibility.
I am also thinking that She would be better designed as a full rigged ship rather than a barque, with square sails on all three masts and just a fore-and-aft spanker without the topsail on the gaff. Neater.
In period, she would be closest to a frigate of the Royal Navy circa 1815. After that ship design tended towards slimmer hulls.
Incidentally, I tried to post the design on the Plans thread but found no means of accessing the upload function. Is there one? I also tried the RCSailing Forum, where some discussion of a possible square rigged Footy could be found, but could not get on at all, after waiting for a half hour (I’m on dial-up). Is this others experience as well?
Rod
I am on dial up when at home and can usually get on any RC Groups forum in seconds, so I don’t know what was going on. Sometimes it pays to look at your connection speed. If I get a slow connection I sometimes hang up and try again.
Right now I am enjoying cable access at a friend’s house.
Pete
Getting back to trans ocean crossings by model yachts.
It occured to me that if I let a model go from here the prevailing winds would take it most likely to North America. A simple free sailing model with a transmitting GPS unit on board. No r/c or any control of the model at all. Just a position transmitted daily.
“Follow online the voyage of my Footy to North America” 
I suppose it’s more exciting thn putting te message IN tjhe bottle. Free blown hull? Maybe you could get sponsorshp from a wine-maker?
A:devil3::devil3::devil3::zbeer:
The kids and I do it every summer in Georgian Ban (minus the GPS) … a scratch build of bits of balsa, kite parts, fishing kit and paint … over the years they’ve got harder to let go but the intent is always to let them go … I’m sure they end up trashed by chop and on the rocks within hours but maybe maybe maybe something cool happens to them …