Diesel Fuel Tank Inspection Port?

[Tranona]

I know you said you did not want to use the fuel gauge fitting, but on the rare occasions when you would want to access the fuel can't really see a downside. It is over the deepest part of the tank and taking the sender out is not difficult - and the hole is bigger than you want. Can be a bit tricky getting the little screws back in, but that is the case with all that type of fitting.

 

[nigelmercier]

I know you said you did not want to use the fuel gauge fitting, but on the rare occasions when you would want to access the fuel can't really see a downside. It is over the deepest part of the tank and taking the sender out is not difficult - and the hole is bigger than you want. Can be a bit tricky getting the little screws back in, but that is the case with all that type of fitting.

Why do people so often question one's motives? I have reasons, OK?

 

[Seadawg33]

I didn't realize that the seabuilt access panels were not hinged. This would make it pretty easy to make them. They describe the type of aluminium they are made of so it would just be a matter of cutting the parts out with a hole saw. The top piece would be the hardest because it is round without a a hole in the middle where the pilot drill would go but you could just cut out a square piece to fit on top. Next time I need to install more then one I will look into making mine. For one panel it is hard to get set up.

 

[nimbusgb]

The component parts of the seabuilt ones could be made by water jet cutting very easily. I'd be interested in getting one for my tank. If 4 or 5 of us got together we could get them done for a lot less than the $135 plus postage from the 'States.

Laser cutting a pile of nitrile or neoprene gaskets would take minutes too.

 

[nimbusgb]

Quote this afternoon. For a set of 2 rings ( one split ) and a top cover all in 316 S/S laser cut to fit 4" hole . £28 each if we get 10 sets made.

 

[pvb]

Quote this afternoon. For a set of 2 rings ( one split ) and a top cover all in 316 S/S laser cut to fit 4" hole . £28 each if we get 10 sets made.

Why 2 rings plus a cover? The Seabuilt product just has one split ring for inside and a cover for outside.

 

[Seadawg33]

Quote this afternoon. For a set of 2 rings ( one split ) and a top cover all in 316 S/S laser cut to fit 4" hole . £28 each if we get 10 sets made.

It would still be cheaper for me to order them thru you but I have already ordered one of the units in aluminium. In my experience a 4" hole is really tight to use as an access hole to clean the tank. 6" is much better if you have the room.

 

[nimbusgb]

why 2 rings?

Inside the tank - split ring with 12 holes - all tapped.
Outside tank - solid ring 12 holes all clear drilled 6 of which are countersunk. 6 screws hold the 'sandwich' together using csk screws. The next 6 screws hold the cover on. When the cover is removed on the Seabuilt one how is the inner ring held in place?

I'll get a quote on 125mm and 150mm but I'd like 2 hatches so I wantto keep them cheaper ( I have an internal baffle and need one each side of the baffle. )

 

[nigelmercier]

This thread seems to have gone away from my original question. I was thinking of something like this, with a cap on the end;

 

[pvb]

When the cover is removed on the Seabuilt one how is the inner ring held in place?

By the outer gasket, which is a snug fit on the bolts.

You're introducing a third gasket, which is another potential leak point.

 

[pvb]

This thread seems to have gone away from my original question. I was thinking of using something like this, with a cap on the end;

That'll work, but you'll need access inside the tank to fit it. If you don't have access, you can use an Essex flange instead as already suggested.

 

[Seadawg33]

why 2 rings?

Inside the tank - split ring with 12 holes - all tapped.
Outside tank - solid ring 12 holes all clear drilled 6 of which are countersunk. 6 screws hold the 'sandwich' together using csk screws. The next 6 screws hold the cover on. When the cover is removed on the Seabuilt one how is the inner ring held in place?

I'll get a quote on 125mm and 150mm but I'd like 2 hatches so I wantto keep them cheaper ( I have an internal baffle and need one each side of the baffle. )

The inner ring is actually held in place by the outer gasket. The bolt holes for the outer gasket are drilled/cut a little too small so that you need to thread the bolts thru the gasket and this holds the inner split ring in place. None of the holes on the rings have threads. I added a small dab or permatex sealant on the heads of the bolts. This worked as a soft adhesive to hold the bolts in place. I bet with the decrease in work that you will be able to get the panels in a larger size for the same price.

 

[Spyro]

why 2 rings?

Inside the tank - split ring with 12 holes - all tapped.
Outside tank - solid ring 12 holes all clear drilled 6 of which are countersunk. 6 screws hold the 'sandwich' together using csk screws. The next 6 screws hold the cover on. When the cover is removed on the Seabuilt one how is the inner ring held in place?

I'll get a quote on 125mm and 150mm but I'd like 2 hatches so I wantto keep them cheaper ( I have an internal baffle and need one each side of the baffle. )

http://www.seabuilt.com/demo.php

See the demo.
The internal ring is held in place because it has studs attached which are held with the gasket once they are poked through the holes. The outer plate is held on with nuts.

Back to the drawing board.

 

[nigelmercier]

http://www.seabuilt.com/demo.php
Back to the drawing board.

Although this is not what I had in mind, I don't think it's that hard to make in quantity.

Just make a load of rings, all identical. Half then have tapped holes and are cut in half, the others have larger holes. Screw in machine screws with epoxy on the top of the threads, or spot weld if thought necessary. All gaskets can be identical, tight on the screws.

 

[nimbusgb]

You don't need a gasket inside the tank, just one under the top stiffener and one for the cap itself.

 

[Spyro]

You don't need a gasket inside the tank, just one under the top stiffener and one for the cap itself.

No but it helps hold the 2 halves of the ring together another option is make the hole and ring Oval shaped then no need to split the inner ring.

 

[sailinglegend420]

This thread seems to have gone away from my original question. I was thinking of something like this, with a cap on the end;

It's a great pity you get to many "opinions" on this site and not helpful answers to your original question. People with nothing better to do should go to the Lounge or Scuttlebutt.

We had the same problems as you. Diesel bug caused huge black deposits around the wall of the tank and lumps of jelly in the bottom. The answer was to steam clean the tank and remove "ALL" the mess.

We went for two inspection hatches which allowed me to get my arm in and clean the whole area because the steam cleaner we hired didn't really do the job. This meant finding a cement that would stick ABS plastic to Polyethelene. Eventyally found an expensive 3M product that seemed to work. I made up two split backing plates as described above to give some rigidity. The problem was they didn't give enough rigidity, and the 3M cement was broiken down by the diesel. This was not mentioned on their website for the product.

The solution now has been to make a rigid support plate on top of the plastic tank to stop the top of the tank bending and collapsing. The hatch cover was bending so much that it wouldn't undo. The gasket used now is nitrile and all seems to be working well.

Every two years we now clean out the tank easily -because we can - and remove all the cr*p. We use Fuel Set which is meant to kill the bugs and then pass them through the filters where they get burn't in the engine. This last winter there was a jelly that was so thick it was difficult even to scoop it up into a bowl.

After the bug we got 5 years ago when the filters were clogging with black gunge we now never have a problem because we keep on top of it. they call it "preventitive maintenance" - some readers here should try it!

 

[nigelmercier]

It's a great pity you get to many "opinions" on this site and not helpful answers to your original question...
We had the same problems as you...

Thanks for your reply. Actually, I haven't said why I wanted the inspection port, I thought it would just complicate matters; I figured that "dip, sample and drain" was enough to explain my requirement.

OK, here goes, but this is totally irrelevant so please no "try this" suggestions!

I've built an electronic digital fuel gauge, working off the original sensor. During my trials I discovered that the sender float did not reach the top or the bottom of the tank, so I want to extend the arm. To do this, I need to get a laparoscope into the tank at the same time as the sender unit is in place; hence the need for an inspection port. It will also allow me to drain the tank to calibrate the unit. At present, I do not have the diesel bug.

So now you see why I just need a small inspection port, and I thought these would be fairly common. My mistake.