We have always had PC’s on our boats, even as far back as the late 1980’s when this was really rare. On our old C&C 35 we had a military grade laptop computer with a magnesium case made by a long defunct company called GRID Systems. The GRID was indestructible and a forerunner of the Panasonic Toughbooks which many cruisers use today.
Our desire to have a PC on board comes from the time when we both worked on computer hardware that was intended for use in environments even more hostile than the southern ocean, or more specifically space. Over the past couple of decades our standards and requirements for a boat PC have evolved greatly. It should be no surprise that when we were building Makara we struggled to find a commercial solution that both met our needs and requirements. Oddly enough we found that using off the shelf components we have been able assemble a PC which is both exceedingly reliable, low in power, fast enough to run the suite of application software we use, yet doesn’t dig a deep hole in the cruising kitty. In fact, the PC described below, not including cables and software, costs a total of $832. The purpose of this log is to share that experience so others may also leverage what has in effect been a twenty year journey.
From our perspective the key things that distinguish an ocean going PC from one intended to live on the dirt are as follows:
- It must be easily mounted and be reasonably small
- It must run on 12 (or 24) volts
- It must be low power
- It must be impervious to shock and vibration
- It must be exceedingly reliable
- It must have connectivity to interface with the variety of marine instrumentation
On the requirements outlined above, you will note that being water proof or water resistant isn’t one of our requirements. This too comes from years of experience and the realization that if enough water to cause damage gets to where the PC is located on the boat, we have WAY bigger problems than a dead PC. In fact, if you consider other marine equipment like a SSB radio, or some components in instrumentation systems, these are not water proof either.
As far as meeting the 6 requirements above, fortunately the niche demand for PC’s used in the cars, the evolution of Netbook PC’s, the explosion in USB and LAN based marine instruments, and advancement in storage technology has made all of these requirements readily achievable using COTS (Consumer Off The Shelf) components. In the following we discuss how we achieve each of these requirements.
Size and Mounting
When considering a boat PC, the first question one might ask is why not simply use a laptop computer? It is a reasonable question and for many, using a laptop may absolutely be the correct answer. In the past and in our earliest attempts at integrating a PC on board we went down this path. Over the years we have come to believe that the integrated display of the typical clam-shell design of laptops is less than optimal in a nav-station. We much prefer the idea of a separate computer and display. This allows us to both get a much better ergonomics of display positioning, gives us much better power control over what is on or off, and avoids a lot of the inherent issues associated with strapping down a laptop PC.
On larger power boats and commercial vessels which have 120V AC generators running all the time it is pretty common to see a standard desk top PC used. Fortunately for those of us on sailboats and smaller vessels the form factor of PC technology has evolved and there are a lot of choices out there. The form factor of a PC is pretty much defined by the “motherboard” which really is the heart of the PC. For many years the standard for desktop PC’s was something called the standard ATX form factor. This siz
e of motherboard is what is in most old desktop PC’s and is really too big for a boat. In the first generation of Makara’s PC we utilized a Micro-ATX motherboard which offered a much more compact PC that would just fit inside the space that we had designed for it. In the latest evolution of Makara’s PC, due to some advances in processor technology for Netbook PC’s, we have migrated to a Mini-ITX style motherboard. The relevance of the motherboard type picked is that this dictates case size.
There are a plethora of PC cases available in every shape size and color you can imagine. What I look for in a case is the quality of materials used and the thermal design of the case (those PC motherboard above are little heaters and the heat from them needs to easily escape otherwise they will shut down. Although there are some good cases available from companies like Antec and Coolermaster, I prefer the cases made by Thermaltake. The specific case I like, shown at the left, is called the Element Q, and is designed for home theater applications. It is compact measuring only 13” (330mm) deep, 8.6” (220mm) wide and 5.1” (130mm) high. Using Perko hardware designed for fastening table legs this case can be firmly mounted on the boat yet is removable when required. As is normal for marine hardware two of the Perko fasteners costs as much as the PC case. Total investment $80 for the case and $80 for the mounting hardware of $160.
Running on 12V
Anyone who has ever had to deal with electrical problems on a boat knows that the battery power is always in short supply and, especially when charging, can damage more sensitive electronics. Given that reliability is critical to us in the first generation of Makara’s PC I sourced a very expensive 12V industrial computer power supply that was intended for use in the telecommunications industry. Fortunately more recently, primarily due to the explosion of the use of PC’s in the auto market for digital music a number of new high quality and low cost power supplies have become available. Of these, the best of the best is the M4-ATX made by Mini-box. This is a very reliable 12V power supply intended to work off of very dirty 12V power. The other great thing about the M4-ATX is that it has both the ability to control turning on and off the PC motherboard but has lots of protection built in specifically designed to prevent it from draining the battery. In a car, if the battery were to get drained, you would have the inconvenience of needing a “jump”, on a boat this is a much bigger deal and this protection feature is wonderful. Last but not least this power supply sells for $92 (including the case) bringing our total investment to $252.
Low Power
The single component in a PC that “eats” the most power is the CPU or processor. To put it in perspective that Intel CPU in that fancy new laptop uses 73 Watts of power (for Core i5), or nearly 7 amp hours JUST FOR THE CPU. Even though Makara is a moderate size boat with a big house battery bank, we are very conscious of power consumption preferring to rely on our solar panels, as opposed to DC generator to keep the house bank topped off. This stinginess toward power usage ranges from our use of LED lighting on the boat all the way to the boat PC. Fortunately the popularity of Netbook PC’s has spawned a new generation of CPU’s that are both fast and power efficient. Intel’s ATOM family of processors, specifically the ATOM 330 processor is speedy enough for charting applications yet only uses 8 Watts of power.
There are a wide variety of Mini-ITX motherboards available that support the ATOM 330 processor from well known manufacturers such as Asus, Jetway and Supermicro. For Makara I chose the IONITX-G-E motherboard from Zotac. This choice was largely dictated by the quality of the board as well as the large number of USB ports (10). To complete the core of our PC we simply need to add 4GB of memory, and from hard earned experience we always buy the highest quality memory we can from companies like Corsair or Crucial – NEVER off brand memory. At $159 for the board and ATOM processor, plus $100 for 4GB of memory the investment in our PC is now up to $511.
Shock, Vibration and Reliability
In the past the component most likely to fail on a boat PC was the hard disk. Other than fans, this is the only electromechanical component in the PC, with a motor spinning away at 5400 RPM. Is it any surprise that when a 16 ton sailboat slams down into the water after coming of the top of a wave with a bone jarring G-forces that a spinning hard disk might fail? Again, fortunately due to the magic of Moore’s law (which says that the number of transistors that can be put on a chip doubles roughly every 18 months) boaters no longer have to worry about spinning hard disks. Although the single most expensive component in our boat PC, the use of a Solid State Disk (SSD) is the single differentiator in insuring the reliability of Makara’s PC versus commercial solutions. As the name implies, SSD’s are solid state, with storage occurring on chips as opposed to a spinning magnetic disk, and as such are pretty much impervious to shock and vibration. As a side benefit they are also low power and exceedingly fast. The only rub is they cost a lot more than a conventional hard disk. To put this in perspective, an 80GB conventional hard disk can be purchased for around $42. The equivalent sized SSD (also from Intel) costs $210 (5 times as much). A warning here, this is the single component that you would be wise not to compromise on.
On hard disk size, some may think that a mere 80GB is not enough storage when they are used to their smart phones having almost this much storage. This raises an important point about how the PC on Makara is used – which is specifically for navigation, communication, and simple record keeping. If the PC is restricted to these mission specific uses, and we reserve our personal laptops for photo processing, digital music and media, and the other gigabyte memory hogs, 80GB is more than adequate.
Our PC is now nearly finished, and with the addition of an Intel X25-M 80GB hard drive at $210, and an inexpensive CD-ROM to load software at $25 the total investment in our PC is up to $745.
Connectivity
The last criteria we need to meet, which relates to really using the PC in a boat environment, are the ability to connect it to the various systems on the boat. Most instruments and communication equipment in use today rely on three primary interfaces, legacy RS232 (Serial), USB, and LAN.
In modern COTS computer equipment RS232 or Serial interfaces have all but disappeared, yet it is still common for AIS, Sideband Radios and Modems, as well as NEMA 0183 instruments to use RS232. Fortunately there is an easy and relatively low cost solution to solve this problem: the Serial to USB converter. Although there are cheap solutions available which are effectively a cable with a USB connector on one end and a serial connector on the other end which can cost under $10 I prefer a somewhat more industrial solution in the form of the Startech two port USB to serial adapter. Although this device sells for $55, it is easily mountable near my instruments, and allows me run a single cable from the instruments to the boat PC.
The last bit of connectivity that we need to add to complete a boat PC may not be required by everyone, but on our boat which has a Raymarine E-series instrumentation suite that uses a RJ-45 LAN connection we need to add a second network interface. Fortunately this is easily and cheaply done with an Intel PCI Express network adapter which costs only $32.
With the addition of the $55 USB/RS232 box and a $32 network card the investment in our boat PC, which is now complete, totals $832. This of course excludes software like Microsoft Windows (XP, NOT Vista or Version 7) and a few cables, but reasonably compares to using other solutions like a laptop PC. The benefit we get for this investment, plus a little sweat equity, is a state of the art, readily upgradeable, bullet proof PC ready to take on the oceans.