New Fuel Tank Sender - No Drilling

[Chuncky]

Our boat has an opaque 'plastic' fuel tank. In tha absence of a fuel gauge, monitoring of the fuel level invoves me dangling my wife upside down in the 'big locker' to determine how much/little diesel is in the tank. She has expressed a modicum of reluctance to this exercise. One of the winter jobs this year has involved clearing out some ducts around tehthe top of the tank - to reveal an 'inspection plug' on the top of the tank. It's 60mm in diameter and is relatively easily removed (whilst the infrastructure is out of the way). 'Result' thinks I - we can fit a fuel sender and gauge. Some research shows that the only threaded senders available are 1.25" thread - too small for my 60mm opening. I don't know what the thread pattern of the existing 60mm cap is, unfortuanetly.

I'd really like to use this existing aperture to fit a sender - any suggestions? 60mm - 1.25" reducer - does such a thing exist? Whast is the likely thread pattern of the existing 60mm cap?

I have a plan B involving a raspbery pi and sensors stuck to the outside of the tank, but the existing hole seems like an opportunity that I can't pass up.

Thanks for sharing any experience/suggestions.

 

[Paul1962]

Why not tap the existing 60mm plug with a central 1.25" thread ro suit the Sender?

 

[andsarkit]

Would this be any good?

Furneaux Riddall
You could pot it into the existing bung with Sikaflex maybe with a few bolts to ensure mechanical security when you unscrew it. Don't know what length you need.

 

[Chuncky]

Why not tap the existing 60mm plug with a central 1.25" thread ro suit the Sender?

I had pondered this, but there's not much material to tap at the bottom of the plug, unfortunately.

 

[Chuncky]

Would this be any good?
View attachment 189708
Furneaux Riddall
You could pot it into the existing bung with Sikaflex maybe with a few bolts to ensure mechanical security when you unscrew it. Don't know what length you need.

That looks like a possibility, although I don't think that I could use the bolts - they'd be right at the edge of the existing cap. Potting with sikaflex definitely worth considering. I'll try to source a spare cap first, in case it all goes awry.

 

[andsarkit]

You could probably drill a couple of new holes in a suitable location to suit the cap. You will need something protruding above the flange to get a purchase to unscrew the cap for maintenance which might be quite tight.

 

[PCUK]

Fit the sender into the cap in the same manner as you would fit it in the tank top. Simples!

 

[MontyMariner]

I had pondered this, but there's not much material to tap at the bottom of the plug, unfortunately.

If the sender comes with a backing nut, no problem, if not, source / tap a disk to make one.

 

[vyv_cox]

Why not cut a new hole in the top? Trying to use the existing screwed lid seems to be making life difficult for yourself. The Osculati unit I fitted to my stainless steel tank is shown and described here. Sadler 34 fuel tank

 

[justanothersailboat]

I can understand the reluctance to cut, given the need to take the tank out and really completely empty it, and then the difficulty of getting any cutting mess out of the tank. It's a bigger job.

Everybody needs a mate with a lathe and a set of thread gauges... I would offer, but at the moment I am "drowning not waving" and you can't wait as long as I would take.

 

[DJE]

Each to his own but I find one of these much easier to dangle than a wife.

https://m.media-amazon.com/images/I/413ncga9XwL._AC_UF1000,1000_QL80_FMwebp_.jpg

 

[alahol2]

This looks like it should fit your hole...
From TekTanks.

 

[Big John]

I fitted one of these to a friends boat. Luckily he also had a plastic tank. Drilled a hole close to the inspection tank hole to allow your hand to reach in with the nuts to secure the sender to the plastic. I had a plate made up as a backing to the nuts securing to the underside. Comes complete with the guage and cables. Wire up as the diagram. You just need to measure the depth of the tank to get the correct sender.

0–190 Ohm Kraftstoff-Schwimmersensor + 52 mm Kraftstoffstandsanzeige, 7-Farben-Licht, wasserdicht, IP67, Öltank-Messgerät, Anzeige, Auto, Yacht, 12 V, 24 V - AliExpress 34

 

[Chuncky]

Update. My local blacksmith created an adaptor for me by turning down and threading a block of nylon.

I sourced a 1.25in threaded sender and he made an adaptor into which the sender screws. The adaptor and sender then screw into the aperture in the tank.