Sorry, my quip on "under the dodger" was not in any way directed at you. It arose from discussions years ago that left me very disappointed in my fellow cruisers. Again, I'm sorry, I shouldn't have mentioned it. I'll delete it.
DIY Sailing Instrument
- Thread starter brett_howard
- Start date
Kinda seem to have some cutouts in the sides finally designed in that I don't hate but I've not yet tried printing them to prove they'll print well. I think they should be supportable.
But I've also got the pixel ring working, the compass working, temp read out (that is way high due to self heating I believe). Barometric pressure seems good and GPS working SD card logging is working. I'm not sure if I'll get to integrating the wind instrument over LoRa until the summer but that should be relatively quick and easy considering how well the initial bring up has been going...
I plan to bring over the functionality into this one from the last instrument where it can have a "home" slip location where it will start and end a trip... Then when you come home and enter into Logbook mode it will tell you statistics about your trip. Things like the date and start time and end time. Then on page 2 it currently shows average wind speed, average wind true wind direction, and max wind speed. Then a 3rd log book screen currently shows Barometric pressure, Max Heel Angle, and Average Boat speed over ground. These 3 pages are cycled through at 6 second intervals (as that makes it easier for me to write them down).
I've also gotten the case designed and the electronics together for an NMEA datalogger that I'll be working up hopefully soon too.
I think I've also got some thoughts about a way to be able to read the engine RPM off the Balmar Tach signal and transmit that onto the NMEA bus.... Then once I've got that I think another NMEA2000 unit that reads from the tank and from the RPM and gives range estimates like a new car could be fun. Granted I'm constantly doing this math in my head. But it sure would be nice to have another gizmo there to argue with on who was right?
Anyway I'm having fun... Hopefully this is of interest to more than just I.
It certainly looks like you are having fun. Now don't take anything I say in a negative way, I'm genuinely curious. I guess I have to say that I must be what one would call an "old time" sailor. I tend to look at all systems on a boat from a "need to have" perspective. I also look at any system coming onto my boat with an eye to how long will it last and how much work will it take me to keep it functional. I'm a firm believer in the K.I.S.S. principal, especially on a boat. Well, at least as much as reasonable....
That said, from my perspective, anything that is electronic needs to be seriously considered as electronics and sea water have a very active mutual hate. I have opened up so called marine grade electronics and found them to be really lacking in internal construction.
I don't understand the reasons why folks want so many electronics on a sailboat. What is the real purpose? I understand there is a "cool" factor. But what real function(s) are they providing? My number 1 sailing aid is my Windex that sits on top of my mast. 0 electronics - flawless execution.
My number 1 weather prediction is Star Link giving me broadband Internet and all that that provides. I also have traditional barometer, hygrometer, thermometer gauges.
A major concern I have with all these "gadgets" is the long term viability. The constant changes occurring in the electronics world means these become obsolete at a rate that I personally won't tolerate. You even alluded to this when taking about the change in libraries...
I'm not opposed to electronics but only when I feel sufficient need. I do run RADAR, AIS, communications equipment and navigation equipment. And the above stated Starlink and required equipment.
But I'm at somewhat of a loss to see a real need for the equipment you are working on. Now that said, I will add that I could see using this type of equipment for 2 purposes. 1) if you are tied into a group like Sea Keepers that is doing a lot of work on ocean sustainability. 2) to keep track of miles for documentation purposes for Coast Guard licensing and the like.
I feel if you seriously want to have a market for what you are building, you need to establish need. Then build to address that need.
Some random thoughts based on what I've read.
In your first post you said you use brass inserts in your box. I'd recommend you move to monel. Brass will corrode far to quickly. Monel would be much better. There are other materials that could work better than brass.
How are you sealing your internal electronics to keep them from corroding? I think this is one of the most overlooked aspects of marine grade electronics that I've observed.
dj
I like having the data from the “black box” I built and I’ve used it for a few things. For one thing after a race I can go back and look at things like my lines and tack angles to see what I could’ve done better. I’ve also used it to compare my tack angles and polar speeds between original sails when new, to 10 years old, to the replacement sails being bought. Comparing the original performance to 10 years old factored into our decision making on when they were worth replacing, and seeing the old performance come back with new sails was rewarding. I could do that by “feel” too but it was nice to have some data to back it up. I’ve also used it to look back at depth data going through unfamiliar channels to confirm I could get back through them at a lower tide (or figure out what I did wrong if I bumped once).
As far as the “cool” factor - yeah, I look at it for that too. I’ll go back and see “what was my highest heel angle”, “how windy were the gusts in that storm”, and those types of things.
I think this is a one-off build for his own enjoyment. While he might freely share the information and files needed to build one, I didn't get the impression he was aiming for commercial production. He also stated many times that the functions he put into it were highly personalized for his desires. In addition, I think he said this instrument was for his little boat that didn't have any other instruments, and that his larger boat had commercial stuff.
I'd disagree that commercial electronics become obsolete at a rate that is unacceptable. Obsolete means they can't be used anymore, not that the manufacturer no longer makes them. How many 20yr old Raymarine ST60 systems are still being used just fine? Our Vesper AIS, which stopped being produced many years ago, still does what it was designed to do.
Electronics are a personal thing. There are many people who argue one only needs a windex or piece of yarn on a shroud to get all the wind data they need, but mostly they don't do multiday passages or don't find value in an autopilot steering to a wind angle. Can one forgo radar? Sure, but I wouldn't because we are often in shipping lanes, places with lots of small fishing vessels without AIS, and poorly charted areas where radar helps define the land masses.
If you have wind, depth, speed, GPS, navigation, radar, ais, it sounds like you have a lot of electronics already. At least much more than many who rail against electronics. I've found in general that people complaining about others have too much electronics is because they have more electronics than them. It is a sliding scale!
Things like data loggers and the like might seem like electronics for the point of electronics, but they can actually make one a better sailor, a better navigator, and a better weatherman. Reviewing continuous trip data in context of decisions made or how the boat was sailed is exactly what professional sailors do to better themselves. Using these types of systems to automatically build real-life polars for the boat in various weather and sea conditions and various sailplans will make passages faster and safer.
Mark
This is a good point that I forgot to mention in my reply. In addition to wanting the data I built my recorder because I like to tinker with technology, and I was able to learn some new things with it. I wrote the code originally in Java but after a couple years I saw a big trend toward Python so I reimplemented it there as a way to learn a new language. This winter I’ve been playing around with refactoring the code with Gemini AI mostly as a way to learn AI best practices and what it’s good for.
Not unlike sailing, sometimes the destination isn’t the goal, but the process of getting there is.
I've been following this with much interest! For the record, my electronics currently consist of a depth sounder, a sometimes-functional knotmeter, and an iPhone. I sailed just fine this past year without even a windex (the yard lost it....grrr).
But I really want a good data logger and am moving toward adding electronics for such. I've had several recent trips where I thought, "man, it was really blowing out there." I wonder if that was 25 kt? 30? I have no frame of reference. Local weather reports are terrible at predicting actual winds on the bay so they're useless. I also want to know how well my boat and I are doing under certain conditions, and I'm a data junkie who wants it all in my trip logs. It would help me track my progress as a sailor and help me with future trip planning. Most of all, it's fun and interesting! I am separately working on a way to capture N2K data with a python script and a $25 USB-CAN adapter that I hope to be able to share in the near future.
Furthermore, when I'm on the water, I just want to be sailing. There's enough to do without keeping a meticulous log, and I'm especially bad at remembering to do those sorts of tasks. I'm accustomed to technology being able to automate that for me and want my boat to do it too. It's a quality of life thing.
But I really want a good data logger and am moving toward adding electronics for such. I've had several recent trips where I thought, "man, it was really blowing out there." I wonder if that was 25 kt? 30? I have no frame of reference. Local weather reports are terrible at predicting actual winds on the bay so they're useless. I also want to know how well my boat and I are doing under certain conditions, and I'm a data junkie who wants it all in my trip logs. It would help me track my progress as a sailor and help me with future trip planning. Most of all, it's fun and interesting! I am separately working on a way to capture N2K data with a python script and a $25 USB-CAN adapter that I hope to be able to share in the near future.
Furthermore, when I'm on the water, I just want to be sailing. There's enough to do without keeping a meticulous log, and I'm especially bad at remembering to do those sorts of tasks. I'm accustomed to technology being able to automate that for me and want my boat to do it too. It's a quality of life thing.
Sounds like the thing your making is very similar to the datalogger I'm working on. The Can adapter I'm using is 20 bucks from Adafruit but its probably only 3-5 dollars worth of parts... Then 10 bucks for the Adalogger I added which really I only needed for the SD card slot. If someone made a commercial one you could probably get it under 10 bucks.
I'm totally with you on the was that 25 knots or 30 knots... or wow we really got a heck of a puff on that spin set what level of heel do you think we got to? I'd also be interested to monitor fuel over time which is also why I'd like to get RPM added in when/if I get a chance.
I've also added a USB hole to the datalogger I put together and wrote quick function that will dump all NMEA traffic out the serial port so one can just monitor traffic on the network. Then with Python there one could easily filter to just one particular device or message type... I hope to get over to the big boat soon so I can connect this up and get it going. But with Python and using Gemini for help writing things I think I should have it writing GPX files with all my network data in a couple days once I'm on the boat.
Interesting idea... Once the wind instrument gets stable I could probably start working on a polar calculator.... How does one usually do that just keep the maximum speed for each angle? But then it seems you'd get different polars for different wind speeds... Not sure if they are things that should be built up by averages over a longer period or if they are more conditional... I think that playing with trying to build that could be a really good way to learn more about them.
I originally built this instrument written in C++ 5 or 6 years ago and that instrument is still working just fine. The only piece that broke was the anemometer connection broke and that happened because something fell on the connection. Its on a smaller boat on fresh water and it's stored inside and it's not sealed at all.
I used brass inserts because they're what I have and they work great. If they corrode in 5+ years time I'll just 3D print a new case and move the electronics over.
But really I see this as an opportunity to learn sailing better and to learn electronics and software design better. I see the idea of electronics and code that I need to debug giving me a reason to go sailing as a high quality problem.
If you want to make something commercial and if you're trying to sell something then you have to deal with customers who are always going to come up with something to complain about. I'm just looking for other like minded sailors who maybe aren't as good as I am in one are but are better in other areas and wants to play with some of these bits.
I'm not looking to get anything from anyone I'm only playing around and giving away the efforts.
You get it its very custom to what I want it to do... The first one is much more fixed in its implementation where this second one is less custom and more built for others to tweak it and make it do many other things... I really like the idea of learning how to get it to output polar plots for a boat and sail combination.... I just don't know if polars are a thing that one does in a trip or in a month of trips... But that is how we learn! Ask questions you don't know the answer to and figure it out.I think this is a one-off build for his own enjoyment. While he might freely share the information and files needed to build one, I didn't get the impression he was aiming for commercial production. He also stated many times that the functions he put into it were highly personalized for his desires. In addition, I think he said this instrument was for his little boat that didn't have any other instruments, and that his larger boat had commercial stuff.
I'd disagree that commercial electronics become obsolete at a rate that is unacceptable. Obsolete means they can't be used anymore, not that the manufacturer no longer makes them. How many 20yr old Raymarine ST60 systems are still being used just fine? Our Vesper AIS, which stopped being produced many years ago, still does what it was designed to do.
Electronics are a personal thing. There are many people who argue one only needs a windex or piece of yarn on a shroud to get all the wind data they need, but mostly they don't do multiday passages or don't find value in an autopilot steering to a wind angle. Can one forgo radar? Sure, but I wouldn't because we are often in shipping lanes, places with lots of small fishing vessels without AIS, and poorly charted areas where radar helps define the land masses.
If you have wind, depth, speed, GPS, navigation, radar, ais, it sounds like you have a lot of electronics already. At least much more than many who rail against electronics. I've found in general that people complaining about others have too much electronics is because they have more electronics than them. It is a sliding scale!
Things like data loggers and the like might seem like electronics for the point of electronics, but they can actually make one a better sailor, a better navigator, and a better weatherman. Reviewing continuous trip data in context of decisions made or how the boat was sailed is exactly what professional sailors do to better themselves. Using these types of systems to automatically build real-life polars for the boat in various weather and sea conditions and various sailplans will make passages faster and safer.
Mark
I'd fully agree with you that its impressive how well working some really old marine electronics can get especially when treated well. I love the B&G display and chart plotter on the big boat they really are handy and I'd not want to get caught in the nasty fog trying to cross the bar with just a GPS and hoping that some big ship isn't coming out that I can't see. Granted a big ship would be on AIS. But I've seen a ton of fishing boats doing 20+ knots over ground running in fog so thick I could barely see my bow roller.
And yes the little boat only has this wind instrument and I try and put all the functionality I can into it because its the only thing on there. Other than a cheap Hawkeye depth sounder I guess...
Yes indeed! The challenge is that sail trim isn't captured by your logger, but I think your maximums approach is probably a good way to extract "best trim" numbers. Just make sure you filter it so that surfing down a wave doesn't mess with your data.
It'll take some careful signal processing to correlate the maximum speeds to wind speeds. I recommend using moving-average or "finite impulse response" type filters; if you use the same window size for all signals, they'll stay synchronized in time. Then you can use interpolation or curve fitting to find boat speed as a function of angle and wind speed.
Don't forget to factor in currents if you have those in your area! You can probably pull them from a tide database somewhere.
I'm already doing moving averages even in the first instrument otherwise numbers tend to jump around too much... And the not having trim I was figuring could be made up for by having a longer term collection to work on finding max achievable. But ya the more averaging would make the numbers a bit lower but I think it would be more realistic/reachable... The wind instrument is just on my lil boat on the lake so current not much of an issue... On the big boat I've got GPS and STW so I can get some inferred currents from that potentially. So many ways to play with these things... I guess we'll see how quickly I get the base instrument functional and what strikes the fancy next.
Basically yes, the maximum wind speed for each angle, with some filtering to remove anomalies. I did some extra filtering to remove measurements when wind angle is changing, or when rudder angle is more than +-5, and for a few seconds after that, to drop measurements from when I'm turning. Then plot boat speed vs true wind angle. Group the wind speeds in, say, 3 knot increments to get the plot in each wind range.
Take a look at the Polar plugin for OpenCPN. It is open source and the source code is published.
Polars are wind speed on one axis and boat speed on the other, each wind speed plotted separately, so they take into account different wind speeds.
They can be built from averages, or maximum, or just plot points at different angles and different wind speeds, and use your data logger to look at the data and determine which you should use.
Mark
Probably a great place to go digging... I've seen quite a few plots just not seen much information on how they get all the information and how long of a session one usually takes to get it... But the wind instrument should have boat speed over ground and wind angle and speeds so I should over time be able to keep collecting values and feeding them into a CSV file on the SD card for plotting in Excel... But it just feels like a true polar plot isn't going to be fully populated from 1 day of sailing.... Unless its a LONG day with lots of wind options and lots of trying to optimize all the angles as best one can...
Something also tells me there is a lot more variability in the graphs than most think.... But with a large set of averages over a longer period of time I'd think it would really start to coalesce around a more consistent and believable set of values...
Yea I totally see a Polar option becoming something this thing can do... Probably just a thing it can do in the background and just keeps populating and refining it over time. Very fun! Very much appreciate the ideas!
Yes, a set of polars won't be generated in a day. Even over a few days with different wind conditions would require one to go out and sail around in all directions for hours paying attention to trim to generate them.
But you are correct that just letting the software collect the data over time is a great way to end up with practical polars. Particularly if you have a sub program that does nothing but associate wind speed and direction with boat speed so you don't have to filter or pick out the data - like the OCPN polar plugin I mentioned.
Most people have a feel for how their boat sails in different winds at different angles, and sailing to polars isn't as important cruising like it is for racing. But polars add another layer of detail to passage planning and weather routing. Many of the weather routing programs can incorporate polars, and this greatly increases the accuracy of the results.
Mark
But you are correct that just letting the software collect the data over time is a great way to end up with practical polars. Particularly if you have a sub program that does nothing but associate wind speed and direction with boat speed so you don't have to filter or pick out the data - like the OCPN polar plugin I mentioned.
Most people have a feel for how their boat sails in different winds at different angles, and sailing to polars isn't as important cruising like it is for racing. But polars add another layer of detail to passage planning and weather routing. Many of the weather routing programs can incorporate polars, and this greatly increases the accuracy of the results.
Mark
Yea I'd seen apps that take in polars and I'd seen published polars for boats but I was always but this isn't my boat... I've got a pretty good feel for how my boat sails and I'm not much of a racer but I've spent a few years as crew racing on the boats of others so I've learned a bit of it... But I think if I sent everything through a somewhat sizable moving average filter which would kill off a lot of the fliers then I could collect maximum's from that and could populate a CSV that could create the plots... I'd think I could get something functional that would start collecting data in a couple weeks. Mostly because it'll take a while to potentially find all the corner cases... But yea that is totally a thing that I need to build into this... Mostly cause it gives much more reason to go sailing to generate the data. hehe
I first used a set of polars from a Valiant 40 thinking it would likely be quite similar to my boat as I have an uncommon boat and could find the polars for this boat. Turns out it was pretty close although it seemed as though either I was a really good sailor to windward or my boat simply sails better than the Valiant to windward. (Guess which it is - coming)....
Then I had a crew member who is a professional racer - big boats, big races. He found the polars for my exact boat - I have no idea where. Running those polars showed that my boat points better than the Valiant 40... LOL....
I'd suggest you find a good set of Polaris for your boat and then use those to run your calculations against. I'd think it would make a cool tool to use as a baseline.
dj
Then I had a crew member who is a professional racer - big boats, big races. He found the polars for my exact boat - I have no idea where. Running those polars showed that my boat points better than the Valiant 40... LOL....
I'd suggest you find a good set of Polaris for your boat and then use those to run your calculations against. I'd think it would make a cool tool to use as a baseline.
dj