Plastic fuel tank inspection hatch???

[Jamie W]

Was looking at installing a 6" hatch on my diesel tank.

 

It could do with a clean.

 

 

This with hylomar blue gasket paste.

 

Would this be suitable to hold pressure/not leak.

 

Cheers

 

 

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[Kingfisher 126]

 

You need to make sure the O ring on the thread is a good seal to start with, if it has one if not it needs one.

If the tank is plastic I would make a couple of horse shoe shaped plates to fit as washers inside the tank, that will be the only way to keep sealing face flat. (3 holes in each plate).

I would also use a gasket to help with the sealing.

 

Those hatches are really designed to keep water out from the outside rather than from the underside if that makes sense!

 

May be worth having a plan B just in case!

[Rob]

also, you need the seals to be fuel proof. There shouldn't be any pressure and I would expect the tank to have a breather.

 

You could always go a a fuel polish instead!

[Mike Fox]

I asked for an inspection tank when my plastic tank was built, and was told it was a weak point.

 

I have a sighting glass as a vertical clear tube from the bottom of the tank, with a ball valve either end with the bottom one permanently open - to check the depth of fuel I open the top one, and the level settles and is visible.

 

The pressure element is critical. My boat was hit with a 3m rogue wave a few years ago, while I had a full tank. The concussive shock wave ruptured the seals on the "lid" . I have little doubt that an inspection hatch you describe would have failed. I'm not suggesting you'll encounter waves of that size, but falling off a smaller wave while travelling at speed could have some dramatic consequences.

 

Could I therefore suggest you consider a sighting glass as Plan B?

 

Mike

PS The return diesel feed of filtered fuel, and regular filter changes should help keep the internals of the tank clean.

[Jamie W]

Oh. After reading all this. I think i'll quit on that idea.

 

Had enough problems. Dont want to couse one.

 

Only a 90l tank. And just wanted to have a hole for cleaning. Even if only once.

 

Some great points.

 

Tanks almost empty. So it was a good time to plan something :-(

[Neal]

If the tank is nearly empty fit a new filter - then try filling the tank a couple of times with Petrol Station "cleaned" fuel. It is a bit more expensive - and then check the filter. you will soon know if the tank is "dirty". 

 

Modern fuels should be pretty clean anyway - If using red Diesel add a fuel additive / cleaner. Diesel bug should be kept at bay if the fuel is topped up regularly.

 

Neal

[Jim]

You need to make sure the O ring on the thread is a good seal to start with, if it has one if not it needs one.

If the tank is plastic I would make a couple of horse shoe shaped plates to fit as washers inside the tank, that will be the only way to keep sealing face flat. (3 holes in each plate).

I would also use a gasket to help with the sealing.

 

Those hatches are really designed to keep water out from the outside rather than from the underside if that makes sense!

 

May be worth having a plan B just in case!

 

I was thinking the same thing about the inside of the tank Chris.

Must be the Engineer in us ! !