This Raspberry Pi Boat Computer Is for Sailors

I would not trust a Pi for anything mission-critical. Get a proper industrial or marine PC.

The one positive about this project would be if it's cheap enough that you could easily get two. However, there could be some batch failure that makes them both unreliable. However, I hear that mariners are wise to such issues, and often get backup systems that are an entirely different brand than their primary.

bit_user said:

I would not trust a Pi for anything mission-critical. Get a proper industrial or marine PC.

The one positive about this project would be if it's cheap enough that you could easily get two. However, there could be some batch failure that makes them both unreliable. However, I hear that mariners are wise to such issues, and often get backup systems that are an entirely different brand than their primary.

Having twice been struck by lightning (once mid-Atlantic, once at anchor in Belize) I notice that nature isn't picky about what brand or make of electronics equipment it destroys. Both times it destroyed both our Raymarine autopilots (yes, so much for backups!). Now I rely on my windvane (Monitor) self steering.

Monitor offer a relatively low-cost autopilot (£800) that drives their self steering for those times when you are motoring in no wind. Meanwhile, I have written my own autopilot that runs very nicely on a £17 Raspberry Pi 3A and uses a £20 12v stepper motor instead of a linear actuator. I certainly wouldn't bother with a "marine computer" - a Pi 4 in an Argon 1 case will do everything you want. And it is tiny enough to fit in your oven or a small cake tin when there is lightning about. Loads of open-source software on the web for chartplotting, autopilots, etc (eg Open CPN, pypilot and so on) and LibreOffice leaves Microsoft Office for dead.

Thanks for the reply. It's great to hear from someone with actual experience, which I clearly lack.

GeoffreyMH said:

Having twice been struck by lightning (once mid-Atlantic, once at anchor in Belize) I notice that nature isn't picky about what brand or make of electronics equipment it destroys. Both times it destroyed both our Raymarine autopilots (yes, so much for backups!). Now I rely on my windvane (Monitor) self steering.

I gather the point about having a backup of a different brand was in case there's a bug or internal defect in the device. As you point out, it's not going to protect you from lightning.

GeoffreyMH said:

I certainly wouldn't bother with a "marine computer" - a Pi 4 in an Argon 1 case will do everything you want. And it is tiny enough to fit in your oven or a small cake tin when there is lightning about. Loads of open-source software on the web for chartplotting, autopilots, etc (eg Open CPN, pypilot and so on) and LibreOffice leaves Microsoft Office for dead.

My concern about using Pi hardware is that it was built primarily to hit a low price point, and not to prioritize robustness or reliability. The first thing you want to look for is ECC memory, but industrial boards will also use higher quality components, PCBs, etc.

In conclusion, I'll just say that if it were my ass on the line, I would go the industrial PC route and not rely on a Pi. Also, beware that flash drives and SSDs have data retention issues, if you leave them unplugged for too long. So, I would chose my storage wisely. Some filesystems, like BTRFS, even have a checksum. So, you can simply check it before launching, to verify that your data is 100% intact.

bit_user said:

Thanks for the reply. It's great to hear from someone with actual experience, which I clearly lack.


I gather the point about having a backup of a different brand was in case there's a bug or internal defect in the device. As you point out, it's not going to protect you from lightning.


My concern about using Pi hardware is that it was built primarily to hit a low price point, and not to prioritize robustness or reliability. The first thing you want to look for is ECC memory, but industrial boards will also use higher quality components, PCBs, etc.

In conclusion, I'll just say that if it were my ass on the line, I would go the industrial PC route and not rely on a Pi. Also, beware that flash drives and SSDs have data retention issues, if you leave them unplugged for too long. So, I would chose my storage wisely. Some filesystems, like BTRFS, even have a checksum. So, you can simply check it before launching, to verify that your data is 100% intact.

The Raspberry Pi was not built to hit a low price point but to educate peope to use computers and electronics-driven equipment. There is now a vast knowledge base on the Pi to support anyone who wants to learn.

Sure, your ass is really on the line when you use any kind of electronics on the boat. Lightning strike is far more common than people tell you - in Florida, for example, 20% of boats get hit a year. Especially vulnerable is the modern diesel engine with electronic not mechanical fuel injection, or the smart (microprocessor-cotrolled) relays that replace a 1-2-Both switch for battery charging.

And then there is the cost. The key sensors of an autopilot (gyroscope, accelerometer and magnetometer) are packaged in the Raspberry Pi Sense Hat for £30 from Amazon. It was tested in space flight. While the B&G "marine" Halcyon Gyro Stabilized Compass Pack costs $1,796. Think of it, the requirements to stabilise a £20 drone are far more rigorous than those to steer a relatively slow-moving sailboat.

Then there is the obsolesence, a huge factor for electronics-intensive power boats. Who is going to service and maintain ten year old systems, and at what cost? Hence the marine electronics engineers's quip: "if it ain't broke, change it out any way". A self-sufficient sailor in the world of electronics needs to be more than able to backup micro SD cards.

Of course such problems go far beyond boats to afflict our modern cars, bikes, etc. A good friend who is a long-distance motor-biker tells of an acquaintance whose fancy new BMW packed up in Kurdistan (fortunately the only one of the 'stans with a BMW dealer). So he put his bike on the back of a pickup and drove the 1400 miles to the nearby dealer... only to find once the diagnostic computer was plugged into his engine that it was an intermitent fault on a light bulb that had immobilised his bike. Swearing to be never caught this way again, he spent £7,000 on a laptop plus all the software to go with it to take on his next trip with him. Needless to say, three weeks into that trip the valuable laptop was stolen.

Live by the sword, and you die by the sword. True. But the Raspberry Pi is a wonderfully cheap and mind-sized little sword!

GeoffreyMH said:

The Raspberry Pi was not built to hit a low price point

Yes, it definitely was. The Pi's creator has previously stated that price was everything. They tried to pack in as many features and as much functionality as they could, and still have an entry price of $35. But, at the end of the day, that price was non-negotiable.

It was not built for reliability or robustness. The overheating problems are evidence of that. The Pi v3 could even be driven to malfunction, under stressful workloads.

GeoffreyMH said:

but to educate peope to use computers and electronics-driven equipment.

Yeah, that's the motive. But that same motive drove them towards maintaining a low price point.

GeoffreyMH said:

There is now a vast knowledge base on the Pi to support anyone who wants to learn.

Which I'm sure is going to be a great source of comfort, when you're stranded in rough seas, with a Pi that keeps crashing or won't boot.

Look, do whatever you want. I was just explaining my concerns, what I'd use, and why. The cost of an industrial PC is probably insignificant, by comparison with boat maintenance, operating, and storage costs.

GeoffreyMH said:

And then there is the cost. The key sensors of an autopilot (gyroscope, accelerometer and magnetometer) are packaged in the Raspberry Pi Sense Hat for £30 from Amazon.

Is there no USB peripheral available with those sensors?

bit_user said:

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GeoffreyMH said:

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Hi bit_user & Geoff,

i read with great interest this debate as a newbie wannabe sailor looking into setting up my own centralized nav system for our soon to be bought cat.
So thank you to you both.

This being said, with the lack of practical experience that i have i'm totally failing to understand you bit_user.

Do you really rely on electronics and proprietary systems for your safety ?

In my understanding this thing is for comfort, to make it easy for the wife & mate to help with navigation during a crossing while i'm sleeping.
it's easy& cheap to backup & it's possible to fix any failure anywhere whenever one component fails (save the topnotch radar antenna obv), you can vacuum bag spare SBC & cards backup, to store in foam coated metallic box. Again it's your own, it's cheap & easy : exactly the opposite of what you propose.

Me inexperienced sailor but software developer for my safety, when thinking about us getting caught by mistake in an unexpected storm i want for my family mechanical backup for autopilot, winds, atm pressure and i want handheld (above) marine grade vhf & gps that can last ages without recharge whatever happens.

Never ever i would consider putting the safety of my family in any PC, even marine grade (industrial grade is way far below, no industry are working in salty environment) and moreover when the software is proprietary.

As a software developer i will cut cost on all the comfort items especially if it helps making them my own & easily & cheaply maintainable or replaceable.
But never i will cut cost on the backup safety stuff (that i hope i will never need but that i believe we all need), whatever the fancy or not, cheap or expensive, nav system we install.