Computank?

[wkearney99]

Anyone have/had a Computank system for their fuel & water? I've got one in my Eastbay and I'd like to entertain alternatives. Mainly to allow for viewing fuel values from the flybridge (as the sole Computank display is at the lower helm).

I'm wondering if it's possible to monitor the Computank's sensors with another bridge, like one from Maretron. This to get it over in an NMEA2k format so I can show it on digital gauges.

The system works presently, so I'm not looking to replace it and it's sensors 'right now'.

 

[mliemon2]

Hi wkearney99 - I know this is pretty old, but did you ever find a bridge to put the computank on N2k?

We have the same thing in out 08' EU 47.

 

[wkearney99]

I did not. It ended up on my to-do list and I haven't revisited it. My sensors continued to work ok so I wasn't pressed to solve it. My investigations at the time pointed me toward putting new sensors into the tanks being the only reasonable solution. Since mine continue to measure effectively I put off pursuing that idea.

As I wandered through some google searches it seems the company doesn't sell or fix those any longer:

We didnt sell enough CompuTank displays (about 1000 in 10 years) to make them worth the effort to build. So we stopped selling them several years ago.

I have other devices from these guys, but have no idea if this is compatible with the Centroid/Computank setup:
https://www.yachtd.com/products/tank_adapter_04.html

The real question is if yours is not working, is it the display or the sender(s)? Because if it's the senders then you'd likely be better served doing a rip-and-replace of both the senders and the display, and go with something modern that already has N2K. That'd be my course of action if a sender died.

 

[twistedtree]

Apparently these were widely used by GB. I had one on an ‘09 47 EU.

I tried to interface it to Maretron and couldn’t. And I don’t think Maretron has changed anything to make it work now. I ended up using pressure sensors to measure fluid levels, and it works very well. You just need to be sure you can install a pressure sensor in plumbing at or below the tank bottom, or used one of maretron’s submersible sensors that can be dropped into the tank from a top port.

 

[wkearney99]

Apparently these were widely used by GB. I had one on an ‘09 47 EU.

And I don’t think Maretron has changed anything to make it work now.

I think Centroid's comment about "not making enough of these" is a pretty good indicator why others haven't put a lot of effort into interfacing to them.

 

[mliemon2]

I emailed Joel at Computank and got a very quick and helpful reply that I thought I'd share. Here's what he said about getting the data on N2k:

The CompuTank has no NEMA2K output, nor do the senders. It's possible to buy adapters to convert the sender output (E0/F4 volts, nominally). Interestingly, the user calibrates the adapter to match the sender, such that the adapter outputs 0-100% to feed the destination device, rather than the raw readings going to the destination device. There are multichannel converters rather than requiring multiple coverters.

Interestingly, when I search "Analog to NMEA multiple channels", sorted by price, all the early hits are on EBay. I see a complication is that most multiple-channel units seem designed for resistance senders, which makes sense since most sensors output resistance rather than voltage. CompuTank senders output voltage.

Ah, this one looks good, though somewhat expensive ($299):

https://acrossoceansystems.com/index.php/product/analog-port-expan/

You'd wire the outputs that are feeding the CompuTank to this device also, and presumably calibrate this device to match the Empty and Full range of the sender. You wouldnt necessarily have to fill the tanks to do the Full cal-- you could use a pvc tube of the appropriate liquid, whether water or diesel fuel.

 

[wkearney99]

I emailed Joel at Computank and got a very quick and helpful reply that I thought I'd share. Here's what he said about getting the data on N2k:

I'd reach out to the Yacht Devices folks with that info. Their efforts to create N2K devices are pretty impressive. Most notably the ability within some of their devices to be able to filter/massage the data in the event of problems or need to rearrange the values for target devices.

I'd be likewise interested in knowing of 'reasonably direct' replacements of the Computank senders, if just to minimize the complications of replacing them.

 

[twistedtree]

If I recall correctly, the Computank senders are standard 5-hole SAE fittings. Does that sound right?


BTW, the issue Joel describes is exactly what I ran into. Their sender outputs 0-5V, bt nobody makes a device that translated that into N2K PGNs for tank levels from 0-100%. The Across Oceans product can sense voltages, but I think it produces battery voltage PGNs, not tank level PGNs. And calibration needs to be included somehow too.


I think the easiest solution is to use the Maretron submersible pressure transducers, and a Maretron FPM100. The submersible transducers come with SAE 5-bolt fittings so I think will directly replace the Computank sender. The submersible senders are about $200 each, and an FPM100 can support up to six of them. If you already have the ability to configure Maretron stuff, I expect this is the least expensive approach, and will support calibrated tank contents for any shape tank. If you aren't already set up with Maretron config capability, it will cost you another $250 or so to buy a USB100. But all in all, I think the pressure-based tank level sensing is one of Maretron's best products.

 

[Firefly2023]

FireFly 47EBFB computank issue

Hello to all you Trawler Folks! My name is Paul Sposato and my vessel is FireFly which is a 47 EastBay FB 2007 which I have had for about two years. Lots of TLC required but mostly done and she looks new at this point but I saw the posts for the Computank fuel system which caught my eye. The MFG isn't user friendly and I am trying to recalibrate the readings on the display but looking for some guidance? Any advice to get me on the right track would be appreciated.

 

[rgano]

Sorry cannot help, Paul, but I want to offer my welcome to this fine forum. I am sure somebody with the knowledge you seek will be along in a minute.

 

[wkearney99]

I have EB47 hull #2 with a computank (that is working) and totally agree with your characterization about support for it. Mine still works, no idea why, and once it dies I'll most likely replace it with Maretron devices.

These are the only docs I've come across for it:

 

[Firefly2023]

Paul/ FireFly EB47

Sorry cannot help, Paul, but I want to offer my welcome to this fine forum. I am sure somebody with the knowledge you seek will be along in a minute.

RGANO: Thanks for your welcome. Calm winds and following seas!! Paul/ Firefly

 

[Firefly2023]

Paul/ FireflyEB47

I have EB47 hull #2 with a computank (that is working) and totally agree with your characterization about support for it. Mine still works, no idea why, and once it dies I'll most likely replace it with Maretron devices.

These are the only docs I've come across for it:

wkearney: Thanks for the info you sent . I will spend some time on it and see if this helps. My EB47 is hull #34; I think they only made 39 of this model.

 

[twistedtree]

I had a similar vintage GB with a Computank and found the attached manual in my files. I think my Computank gauge still worked when I sold the boat, but I had switched to a Maretron pressure sensor based system for primary use.

 

[twistedtree]

I found these too. And my experience with Centroid Products was very similar. Like a lot of marine product "companies", I think it was just one guy in his garage.