Computer Links. NMEA & Data

[Lionhart]

I am building out a 42ft ketch at Hartlepool. What I would like to do is fit a central computer with radar, sonar wind etc coming streight in to the computer. But it seems you nead the receivers in line for some of this ? Has anyone done this sort of set up ? Is it possible, Plausable ?

 

[Talbot]

Welcome to the forums.

feasible - possibly, if you can get the data for the interface from the manufacturer and are capable of writing appropriate software.

sensible - IMHO it is not sensible cause you are creating a single point of failure and although MS is better than it used to be, the old blue screen of death would knock out all your systems in one hit. Furthermore, even with a 12v specialised pc, you will have a significant power drain which unless you are a mobo, would require expensive power generation onboard.

 

[Amphitrite]

Yes, generally that is possible, though most probably you'll need an NMEA multiplexer. This multiplexer will exchange the data between instruments and interface them to the computer. (GPS has to be fed to DSC, radar and autopilot etc.). Make the complete design before buying or you'll be buggered with problems...
Holger

 

[Lionhart]

I will have extensive battery power and as there is going to be no gas on board the cooking is from electric with a 7kva gen. for running- If you are going to have a gen. do it properly ! Does anyone know how much power a computer pulls ?

 

[Talbot]

I understand that a lot of people dont like gas onboard due to safety concerns. Personally I dont like 240v unless I am tied up safe in a marina.

Computer power consumption is very dependent on computer type and what bits are actually running (e.g. hard disc against DVD drive) This can be seen by the increase in size of the power pack in the back of modern PCs with the latest chips and the number of USB attachments (all drawing power) Thus is very hard to answer. 1 gb system is probably in region of 4 amps continuous.

If you are going the route of generator running (dont park near me please), have you considered removing your main engines and replacing with electric drives?

 

[summerwind]

Re: Computer Links. NMEA & Data

What you want to do is not only feasible, its been done by me for one.

As another has said, you will need a NMEA multiplexer. This is because the protocol does not allow more than two talkers on one system without this smart little bit of kit. I got mine from a firm in New Zealand that I found on the net.

The computer is not the hub of the system. As you are creating a peer to peer network, the other pieces of equipment (GPS, autopilot, compass etc) will still talk to each other over the system with the computer switched off, or in standby mode.

You need to make sure that you understand the connections from each piece of equipment to the network as there is no colour code and in my case at least, almost all were different.

The voltages are very small on the network but you will need to feed in 12v + and - from somewhere.

The way I constructed my network was to start with the GPS and connect it to a bus. Then made sure that the comms port on the computer could "see" the GPS NMEA data stream.

I then "Bodge" added the other pieces of equipment one by one and made sure everthing worked before adding the next bit. Once everything was OK, I properly installed the permanent wiring and each of the electronic toys.

I must admit that it took quite a bit of time to get everything working together but all is find now and gives me endless joy.

 

[Lionhart]

The engine will run some power generation as a back up or when under engine it will recharge the batteries. It is powering a pump, which then feeds the motors mounted in cassets inside the boat. These have 2 15 1/2inch prop's in tunnels so that nothing is dragging through the water.

 

[finnlou]

If you want to keep power consumption to a minimum, check out VIA's mini-itx boards, they start at around 12W(and are very small, you can fit a complete PC+drive in a case the size of a car radio), in comparison a 3GHz P4 is around 90W and a lot bigger

figures based on a PC with one 3.5" HD and a CD drive

 

[seashaw]

Have a word with MarineIQ . They can certainly do what you want and have helped me out loads in the past.

Mark