I have a stainless steel diesel tank and need to fit a hatch or lid to better access to the inside of the tank. The hatch will be placed on top of the tank. I'm thinking about using a normal plastic inspection port, but don't know how it can be affected by the diesel. Any advice would be appreciate.

Hi JZ, I did this a couple of years back. I used a Vetus Universal Inspection Port, it's suitable for diesel.
www.keoghsmarine.com.au/vetus-all-purpose-tank-universal-inspection-port-suits-all-sizes-of-atank-ilt120

Whatever you do, don't buy the Vetus holesaw that is supposed to be ok for this, it's not. Have a look at the first pic, that was taken after a good long session trying to get one to cut, it didn't, just polished the SS. I sent it back and got a refund.

The port itself is a good product and I'm happy with it. My tank had poor access inside a cupboard under the galley sink, so cutting the SS was a PITA with a jigsaw. Looks like you've got easier access there, so a jigsaw with a SS cutting blade will make short work of it.

The only issue you might have is with the height of the port, it doesn't look like you've got much room to work with there? hole in the lid so the port protrudes into it maybe?

It would probably be OK. If it was me I would install a plastic filler like this one on a swirl tank. With the cap removed I can get my hand and fore arm in and if I need more room just unbolt the whole unit.
www.ebay.com.au/itm/Universal-2-5-Gallon-10L-Fuel-Cell-Tank-Mirror-Polished-Lightweight-Aluminum-AU/333004788108?hash=item4d88a1d18c:g:HPIAAOSw64xcGtru

Great information. I have a fuel tank that needs an inspection port and this looks like a great option. I am a bit concerned with getting all the metal filings out for a clean tank though. How was this done?

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Guitz said..
Great information. I have a fuel tank that needs an inspection port and this looks like a great option. I am a bit concerned with getting all the metal filings out for a clean tank though. How was this done?

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Guitz said..
Great information. I have a fuel tank that needs an inspection port and this looks like a great option. I am a bit concerned with getting all the metal filings out for a clean tank though. How was this done?

Yes I was bit nervous about that too in the beginning, but in the end it was pretty straight forward. My tank had a bad case of diesel bug, I put in the port to facilitate cleaning that out as thoroughly as possible while it was in situ. On the left hand side of the shot looking into the tank is the baffle, with approx. 30mm space each end, very little of filings went around there and I flushed the tank so much to get rid of the bug residue behind the baffle, that it cleaned out any remaining filings. Mostly I sucked out every thing with my vacuum oil extractor. I reckon that if you clean as thoroughly as possible, make sure your fuel pickup pipe is off the bottom and you have all the requisite filters, then you'll be right.

Don't use a standard plastic round hatch, as the O-ring may not be suitable for hydrocarbons. I have one on the keel water tank, and when there was a bit of an oil leak onto it the o-ring swelled up and had to be replaced (and the leak fixed of course).

Cheers, Graeme

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Ramona said..
It would probably be OK. If it was me I would install a plastic filler like this one on a swirl tank. With the cap removed I can get my hand and fore arm in and if I need more room just unbolt the whole unit.
www.ebay.com.au/itm/Universal-2-5-Gallon-10L-Fuel-Cell-Tank-Mirror-Polished-Lightweight-Aluminum-AU/333004788108?hash=item4d88a1d18c:g:HPIAAOSw64xcGtru

That one Looks like a better option for him Ramona, it's slim and may fit under that cover better. I can also fit my hand and forearm and elbow in the Vetus opening. Must bookmark that one too.

Hi guys, thanks for all the pictures and links shared. I'll consider my options. Cheers

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Guitz said..
Great information. I have a fuel tank that needs an inspection port and this looks like a great option. I am a bit concerned with getting all the metal filings out for a clean tank though. How was this done?

Suck the remnants of the diesel out with an electric pump and have it run through a Cav filter like the diesel polishing units you can see on Youtube. Or just dump the diesel. Wipe the inside of the tank clean with a cloth.

Ok thanks. My tank had the bug and I've removed it so will cut the hole, clean it out then fit the Vetus option.

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Guitz said..
Ok thanks. My tank had the bug and I've removed it so will cut the hole, clean it out then fit the Vetus option.

Ok good one Guitz, hope it goes smoothly for you.

I used this product decontaminate the tank once I cleaned it thoroughly: liquidintelligence.com.au/products/diesel-fuel-bacteria-fungi-biocide-treatments

I also put a small maintenance dose in with each tank fill.

They updated their website. The new link with diesel tank inspection hatches is: www.cleandiesel.com.au/product/190-mm-round-diesel-tank-inspection-hatch-150-series/

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JZOrewa said..
I'm thinking about using a normal plastic inspection port, but don't know how it can be affected by the diesel. Any advice would be appreciate.

You could try one of these plastic ports, made for diesel and comes with all barb fittings included
www.ebay.com.au/itm/Red-Fuel-Hatch-Lid-for-Marine-Caravan-Boat-Multi-Purpose-Holding-Storage-Tank/113027808383

Definitely find a plastic that's compatible with diesel. They tend to get brittle over time.

I would most definitely not be inclined to use a plastic part in that situation, it is an area that gets minimal inspection and is easily forgotten and even the best of plastics can fail without warning for whatever reason.
I much prefer the inherent strength and longevity of stainless steel for things like that