Old school Tank Tender

[Takitimu]

We currently have the old school Tank tender for fuel and water. We are already in a refit to move everything to Raymarine SeatalkNG and Seatalk HS. It would be nice to have the levels on the axium screens. Our boat has both of the tanks built into the hull. Is there a conversion kit or advise? I'm aware the Tank Tender is very reliable and accurate. It's more of a convenience not to have to run to the nav station to see what's going on I thought of a fuel flow meter but that won't help the water level. Many thanks

https://tanktender.com/

[Jolly Roger]

I had a Tank Tender device in my water tanks but I couldn’t stop it leaking air, and it didn’t register the correct amount of water anyway, because the tanks were built into the hull and tapered towards the bottom.

[s/v Jedi]

I hate the gauge senders inside tanks as they always go bad.

I love our TankTender system but, like you, I am looking at replacing it. I have my eyes on the Maretron pressure based sensors with a nmea2000 module that is compatible with your SeatalkNG.

This is the FPM100 and it has six channels. Instead of tanks you can also monitor fuel filters etc.

https://www.maretron.com/products/fpm100.php

It’s expensive because the pressure sensors are required as well.

[noelex 77]

Originally Posted by Jolly Roger

I had a Tank Tender device in my water tanks but I couldn’t stop it leaking air, and it didn’t register the correct amount of water anyway, because the tanks were built into the hull and tapered towards the bottom.

The system needs no electronics or even electricity and is normally very reliable so your failure is unusual. We have used this system on our last two yachts (the one unit measures eight different tanks on our current yacht) over 16 years without any faults or maintenance. The system is still available . See website below:

https://tanktender.com

The Tank Tender simply measures the height of liquid so a table, graph or programmable calculator is needed to convert it into the correct volume measurement. With this you can determine the number of litres or gallons to a high degree of accuracy regardless of tank shape.

[Jammer]

I don't have any advice but would be happy to take the old Tank Tender off your hands once you replace it. Top dollar paid, help out a fellow cruiser, etc etc....

[RaymondR]

Originally Posted by s/v Jedi

I hate the gauge senders inside tanks as they always go bad.

I love our TankTender system but, like you, I am looking at replacing it. I have my eyes on the Maretron pressure based sensors with a nmea2000 module that is compatible with your SeatalkNG.

This is the FPM100 and it has six channels. Instead of tanks you can also monitor fuel filters etc.

https://www.maretron.com/products/fpm100.php

It’s expensive because the pressure sensors are required as well.

Way to go, you can generally T off the hose at the tank outlet and get a good reading and not need to cut holes to install them.

[Takitimu]

Originally Posted by Jammer

I don't have any advice but would be happy to take the old Tank Tender off your hands once you replace it. Top dollar paid, help out a fellow cruiser, etc etc....

I'd be happy to remove it and package it up, long as you pay shipping and promise to pay it forword to another sailor in the future if you have something someone else is in need of. It's going to be about a month before I get to it after I research and get a replacement.

[Takitimu]

Originally Posted by s/v Jedi

I hate the gauge senders inside tanks as they always go bad.

I love our TankTender system but, like you, I am looking at replacing it. I have my eyes on the Maretron pressure based sensors with a nmea2000 module that is compatible with your SeatalkNG.

This is the FPM100 and it has six channels. Instead of tanks you can also monitor fuel filters etc.

https://www.maretron.com/products/fpm100.php

It’s expensive because the pressure sensors are required as well.

Perfect, thanks. That's the direction I was looking for.

[Jammer]

pm sent

[botanybay]

Originally Posted by s/v Jedi

I hate the gauge senders inside tanks as they always go bad.

I love our TankTender system but, like you, I am looking at replacing it. I have my eyes on the Maretron pressure based sensors with a nmea2000 module that is compatible with your SeatalkNG.

This is the FPM100 and it has six channels. Instead of tanks you can also monitor fuel filters etc.

https://www.maretron.com/products/fpm100.php

It’s expensive because the pressure sensors are required as well.

I also installed the FPM100 (Fluid Pressure Monitor I think is what it stands for) with 5 internal to tank level sensors and 1 fuel vacuum level sensor on the NMEA2K and they work really nicely. (Fuel, Water, Reserve Water, Holding Tank 1, Holding Tank 2). So far the internal tank sensors have been working very nicely and are pretty stable when the boat is moving around.

I also have the Hart Level sensor still installed and use as a quick check when the N2K is not powered up.

Interesting that the one in the almost inaccessible holding tank (it is under the battery bank and I have to pull the batteries to remove the cover) all the sudden went from reading normally to reading a full tank (may have slewed over a few days). Hook up a different sensor to the same input on the FPM100 and everything is fine. The forward holding tank has worked fine all season.

A note about leaking Hart, I found that one of the button switches used to direct which tank is being check developed an internal leak. I bypassed that button with hose on the back and the rest of the panel works great. The Hart is not perfect with Sewage either, if you don't routinely check the level of the tank eventually the tube gets covered over with calcium buildup and gets plugged.

I highly recommend the Maretron FPM100 and the internal pressure monitors. I also installed their FFM100 (Fluid Flow Monitor) on the 90hp Perkins M90 and it is amazing to see the impact of optimizing RPM for current, headwinds, motor sailing, and the like.

[botanybay]

Originally Posted by RaymondR

Way to go, you can generally T off the hose at the tank outlet and get a good reading and not need to cut holes to install them.

The line to the in tank sensor is pretty thin (3/8" perhaps) and the provided gland fitting is 3/4" if memory serves. My tanks are fiberglass so I was able to drill and thread the hole and insert the gland fitting.

The sensor itself is larger than this (which is why they have the standard float sensor sized hole adapter) but you can thread the hose up from the inside of the tank and minimize the size of the hole.

On some tanks I used a 90 degree street el to turn the corner (which I opened up a bit with a dremel tool to make the hose go through nicely.

[RaymondR]

Most of the older big semi submersible offshore drill rigs used a pneumatic back pressure system to monitor the dozens of tanks in their underwater pontoons. A metering orifice for each tank supplied the closed top sounding tube in each tank and the back pressure was indicated by a mercury filled U tube manometer. Pretty well the simplest and most maintenance free system one could imagine.

Similar pneumatic systems were used to monitor the levels of drilling mud in the tanks, by putting two sounding tubes at different levels in the tank the density of the fluid could also be measured and compensated for.

[noelex 77]

Originally Posted by botanybay

The Hart is not perfect with Sewage either, if you don't routinely check the level of the tank eventually the tube gets covered over with calcium buildup and gets plugged.

Are you using using a Tank Tender with the purge option (recommended for black water) or the regular model.