Captain’s Log 05/30 – 06/05

May 30, 2021

LoCARB Launched. Immediately began to drift south from intended waypoint. Tested for autopilot malfunction with full reboot to pixhawk and arduino but no change. Upon checking the weather, winds from 12-16mph were observed from 2pm to 11pm. I believe strong winds were blowing the boat off course. Several motion events were recorded which leads me to believe LoCARB is in some slightly turbulent waters. I noticed after 11pm, the boat had begun correcting its course. Its course seems strongly correlated with the high wind forecast.

May 31, 2021

LoCARB made it through the night! Power consumption and behavior is identical to testing prior to launch, so I’m pretty excited. I am very used to the boat failing within the first 4 hours, so this is major progress.

Boat has since corrected its strange southerly course. However, I have noticed the motor pod humidity slowly increasing. Could be a very small leak in the motor/battery pod. I have also changed the update interval from 30 minutes to 1 hour between updates. Boat is averaging 1kt/hr. Motor pod humidity is 42% (launch humidity was 40%).

Leak in motor pod is confirmed. Humidity is now 43%.

*UPDATE 5:33pm*

Humidity in the motor pod is now 44%. It seems that its only a matter of time before the submerged pod will flood. How long this will take I have no idea, but ill keep an eye out on the leak sensor for confirmation of the presence of pooling water.

Navigation: I also realize that the boat isn’t quite powerful enough to overcome much wind force. Because of this, I’m going to try and see if I can ride the wind direction and ride it southwest to almost “come to a landing” towards Hawaii. I’m going to bypass the first waypoint and head towards the second waypoint.

Charging: Not quite as high as I would like at just under 16v for a day of charging, but it should suffice.

June 1, 2021 (LoCARB has reached its first waypoint! Hurray! or not…)

So I woke up today around 5am to check on the boat status and found the boat to be behaving in a way which could point to several malfunctions.

2:27 am: the boat begins to lose headway and is drifting backwards. The motor seems like its reporting back correct rpm, and battery voltage is good. Why is it moving backwards while rpm is OK? Unsure.

3:27 am: the motor RPM drops to 980, which is too far below its target rpm when the auto-throttle is on. It should be at 1030 rpm. Has the motor failed?

4:27 am: the rpm is still 980 which shows that the motor seems to be running at some wonky speed. My thought is maybe its windings or something have given out. Voltage is dropping but still normal, this means the motor is spinning and consuming power.

5:27 am: I get an update which shows voltage is 11.8v which is too low. I send a message to the boat to cut power to the motor. It will take 37 minutes for the boat to process this message at the next update interval.

6:27 am: the voltage has dropped quite low since the motor was running for the last 37 minutes (the batteries have hit its tail end of the discharge curve, so voltage drop will come rapidly). I am happy that the wind/current doesn’t seem to be too strong at LoCARB’s location since it’s just kind of drifting around.

7:27 am: The battery pack is completely empty at a voltage this low. 8.4v/4 is 2.1v per 18650 cell. These cells should only be discharged to 2.5v.

8:27 am: The solar panel is charging the battery pack. Ill keep the motor off till voltage recovers and then begin testing the motor.

9:27 am: Some good news, the battery is back at 11.5v. At ~12.5v ill reboot the Arduino which will turn the motor back on, change the update interval to 30 minutes, and use a throttle setting of 2 (1090 rpm target). If the motor is functioning, we should see some heading towards the second waypoint. If it still drifts, the motor is probably kaput and ill switch to the secondary motor.

10:27 am: Battery charged back up to 12.58v (that was fast!), so I sent a message to the boat to reboot the Arduino at next update.

12:07 pm: Motor seems to be functioning but at a slower rpm. Sent throttle setting of 5. Will see what happens.

THIS IS FUN. I feel like I’m experiencing an entire voyage compressed into the timespan of 2 days. LOL

One of the things I like best about my boat is the various sensors integrated into the electronics. For a boat that is built correctly and doesn’t have any problems, the sensor readings would be somewhat useless. For a boat like mine however, I love being able to utilize the data to help troubleshoot the boat before it stops sending updates. It makes for a fun project.

Also, the submerged motor pod is at 48% humidity. Its still slowly taking on water.

2:07 pm: Ok, some testing on the main motor has found that it does actually function…at high throttle. If throttle setting 5 is sent to the motor, I can get directional control of the boat. If throttle setting 2, it seems I do not get enough thrust for the boat to have directional control and it points north or south.

At throttle 5, charging is non-existent and the voltage drops a little. This is either because the panel doesn’t have full sun or the motor is consuming more than 5 amps to get to its target rpm. This would also lead me to believe that the motor is on its last legs.

The RPM reads also lead me to believe the motor is running less optimally, as it is 30 rpm lower than typical…this is within expectations, but its new and consistent behavior compared to what was happening before the drifting.

I’ve sent a command to switch to the backup thruster, so within an hour or so ill know what we have going on. Also, the humidity is only at 47% now (probably because its not sensitive enough but good for my psyche).

4:25 pm: Too many variables and so little hard data. I’ve reset a new waypoint (more southwest), and rebooted both the autopilot and Arduino. Hopefully this will bring us back to a baseline. I’m thinking something is going on with the solar charging system as it hasn’t charged much…maybe moisture is affecting the buck converter that the solar panel is connected to? Either way, the voltage is too low for a fully powered motoring during dark so ill probably test for a few more hours, turn off propulsion, then have the boat drift overnight to resume testing tomorrow once the sun is out.

5:56 pm: After all the testing today, it could just be that the winds are too strong to overcome. Winds are heading East at 11-12 kts. Ill turn off the motors soon to preserve state of charge and try again tomorrow. The boat seems to be tracking to its new waypoint directly at Hawaii (with no intermediate waypoints). I may need to try and head south and then head west when the winds are more favorable.

6:56 pm: Let’s ride the wind! Motor turned off, and Boat is headed towards Monterey!

June 2, 2021

8:45am: I received the last update from LoCARB at 11:37pm last night. Voltage had dropped too fast the previous 2 updates, which probably means water is in the motor pod shorting out some electronics. If the BMS has not completely shorted, we may hear from LoCARB again once the panel can charge the batteries above 5~8v (even if we do, it wont be for long). If not, LoCARB is dead in the water.

The last update from LoCARB

11:10 am: Well shiver me timbers! The boat is still alive! I’m going to keep the motors off and allow the boat to charge as much as possible today. I will be testing the power system through tomorrow.

1:10 pm: The boat is charging as expected. Lets see how high it can get before dark. It should reach around 15.5v (16.7v is fully charged) before it gets dark tonight.

7:09 pm: LoCARB battery pack hits a voltage high of 14.37v for the day. Not quite my tempo, but acceptable given it was completely dead from the night before.

10:10 pm: Voltage is now 14.24v which means the v drop for the past 3 hours with the motor off has been .13v per hour. This is good news.

11:10 pm: Voltage drop average of .0475 per hour for the last 4 hours. I expect to lose .42v in the next 9 hours.

June 3, 2021

10:09 am: LoCARB did well through the night with a low of 13.55v at the 7am update (.69v drop from 14.24v last night). Maybe I jumped to conclusions about there being a malfunction too quickly? Its possible, I seem to do that often with this boat. It seems that the weather isn’t that conducive to charging so ill need to wait a little bit longer.

24 Hour Data from ARCGIS

I will continue to keep the motors off until LoCARB gets to a full charge. Motor pod humidity doesn’t seem to be increasing at a concerning rate with the motors off either. Maybe there is no leak and the humidity is just a normal byproduct of a warm battery inside a cold tube submerged under the ocean?

I am actually enjoying how quickly the boat is traveling with the wind but will need to have it start moving westward within a few days so I can best position it to take advantage of the wind stream towards Hawaii.

The boat has actually survived much longer than I anticipated…I’m hopeful!

The image below is going to be the new course LoCARB will follow to hopefully take advantage of the wind direction and speed.

1:09 pm: Boat charging speed is a little slow. Upon checking some webcams off Monterey bay, confirmed its very overcast. This explains the slow charging. Whew!

Looking out towards the direction of LoCARB

4:09 pm: LoCARB has charged to 15.62v which is about 80% SOC. I sent a command to the boat to run the motor and update to a waypoint farther southwest. Will test motor performance for 1 hour.

5:19 pm: Motor test seemed to work well, and hit 2 nm within 1 hour (speed of 2kts). Voltage did drop slightly which means ill need to use a slower throttle on really overcast days such as today to conserve enough power for night time use.

8:19 pm: High of 15.7v today with a gain of 2.15v from this mornings low. All in all, an eventful day of motor and real world solar charge testing and watching the boat maintain directional control with wind thrust. Hope to turn on the motor tomorrow!

June 4, 2021

10:19 am: Resuming motor operation. Hopeful that the boat should be able to charge while motor is running. Wind direction also seems to have changed a little bit as the boat is heading on a more southerly direction than before.

Expecting another overcast day of charging with higher southern wind speeds.

NESDIS Realtime Satellite Imagery (updated every 15 minutes)

3:49 pm: LoCARB is confirmed to be functionally sound, but is just hitting some strong winds off the coast. Full throttle shows good directionality. I’m setting the throttle to 1 and letting it motor through the night.

June 5, 2021

9:19 am: My website keeps getting hacked and malicious redirect plugins are installed. I cant seem to find the source, but thankfully its just plugins that I can disable and delete. Anyways besides that, it looks like winds have definitely picked up since last night and LoCARB is having trouble working against them. Its a slow boat with a max speed of 1.5kts so wind speeds of what were we are now facing, this is to be expected. It should be a clear day with full sun, so LoCARB should charge quickly.

I feel comfortable running slightly faster throttle with full sun out. Bumped up throttle to 3.

10:19 am: LoCARB’s rudder is dead.

I just noticed that the temperature of the rudder from the point at which the boat was tracking and from when it began to drift has dropped to 66F.

This can only mean one thing. Either the voltage regulator for the rudder servo has burned out, or the servo controlling the rudder has burned out.

The boat is now completely without directional control.

I’ve turned off the motor. Let’s see how far LoCARB will drift before it dies or hits land.

2:39 pm: I totally believed the servo or voltage regulator had died because I assumed there could be no other reason for the drop in rudder servo temperature. On a whim, I power cycled the autopilot and servo using the relay (which acts like I was there pulling the power plug out for 15 seconds and plugging it back in) and it actually worked!

Here you can see the progression of temperature and directional changes once the systems were reset. Its ALIVE!

7:08 pm: LoCARB voltage of 15.36v before nightfall. I expect voltage to be 12.5v by 8am in the morning. The boat is tracking beautifully despite the winds being quite high. I am curious to know if the previous few days of navigation was caused by a glitch in the autopilot…from now on when I reboot the autopilot I’ll power cycle the relay to the autopilot as well just in case.

The image above shows the current course that LoCARB is on given its waypoint and wind action.

LoCARB is on course to intercept the westward winds which curve towards Hawaii. I need LoCARB to ride the southern winds till it’s in line with Ensenada Mexico, then ride the winds westward. Well, that’s the plan anyway.