How Do You Dip Your Tanks?

[Dockhead]

Originally Posted by s/v Jedi

I just open the sampling valve that is plumbed to the sump of the tank

Another one rubbing it in, instead of suggesting something actually helpful to this specific case



I have that diagram, which you posted some years ago, saved in my file of design features for my next boat. It's almost exactly the way I want the next boat to be set up.

The main difference is I will have a day tank.

[Cheechako]

At those prices I would be installing my own polisher. How much do you actually use your boat?

[Dave22q]

To my tired eyes a far better use of your money is to install redundant fuel filters and monitor what they catch. Then if you see a problem you can drain, filter and replace what ever is in your tank and, if really worried, rinse with a couple of gallons to get most of any residue. Repeat until you see nothing. Instead of $1000 annually you will invest a few hundred one time. More if you need a large bladder to match your tank capacity.

[Dockhead]

Originally Posted by Dave22q

To my tired eyes a far better use of your money is to install redundant fuel filters and monitor what they catch. Then if you see a problem you can drain, filter and replace what ever is in your tank and, if really worried, rinse with a couple of gallons to get most of any residue. Repeat until you see nothing. Instead of $1000 annually you will invest a few hundred one time. More if you need a large bladder to match your tank capacity.

Well, I do have dual Racors and a vacuum gauge, and I do watch them carefully. It was literally the first thing I installed my boat when I bought her.

But that doesn't replace cleaning the tanks regularly, and it doesn't replace monitoring the sump. I had been cleaning the tank not "annually", but every two years, and this whole thread is about wanting to stretch that interval by dipping the tank in order to monitor what is going on in the sump.

A far better system is to have a way to just drain off what is at the very bottom of your tank, like Minaret and Jedi have. Then you can do this at whatever interval you want -- monthly, weekly, whatever -- absolutely the superior way to do this.

The more frequently you can actually have a look at what you have at the bottom of your tank, the less the risk that something will start to happen which will knock out your engine unexpectedly. By the time the crap gets to your filters, it's too late! So what you suggest is not a solution.

[Dockhead]

Originally Posted by Cheechako

At those prices I would be installing my own polisher. How much do you actually use your boat?

A home-made on board polisher is a great thing, but does not replace a real professional scrub of the tank. The pros use a high pressure jet of fuel on a wand to really clean out the tank. If you have a good way of keeping every drop of water out of the sump of the tank (like what Jedi and Minaret have), then you might not need to clean the tanks all that often, but still it must be done from time to time.

As an alternative to the pro system, you could take all the fuel out of the tank and scrub it out by hand -- if you can get to it. That's not an option on my tank which is very large and deep, and only has one access hatch.

[barnakiel]

If there is no sump valve to let out some fuel, you take a roughly 4 ft length of hose and tie it to a rod with cable ties. Some 5 mm diameter or thereabouts.

Lock the top of the tube with your finger and force the rod'ed tube to the lowest point of the tank. Remove your finger. Now place the finger firmly against the top of the tube. Draw the sample, investigate.

If you fill the tank twice a year you are unlikely to develop any serious sediment and given normal filters arrangement (prefilter, filter, engine filter) you are not likely to run into any trouble ever. Sure keep eye on those prefilters - that's why it makes sense to have them at hand (ours sit on top of the tanks and we have a A or B selector to switch them without stopping the engine.

b.

[minaret]

Originally Posted by Dockhead

Yeah, yeah, rub it in.

My next boat will be arranged just like that.

Was that original fit, or did you retrofit it? I think it violates some rule or another, to have holes in the bottom of the tank, but it's a rule I will definitely violate as soon as I get a chance.


Actually, I also thought about installing a permanent dip tube, which would simplify this job. But it never quite made it onto the list.

Original. It's why my thirty + yr old tanks still look pristine. That particular rule varies with locale.

[valhalla360]

Originally Posted by Dockhead

A pipette won't work at all because I don't have 1.5 meters headroom above the inspection hatch to draw it out.

I am going to try the outboard bulb idea with a little plastic hose. Try to pump out into a jar from the bottom of the tank and have a look.

Can still work just need a short length of pipe with a rubber hose fitted to it. The problem with just a rubber hose is it tends to curl so it's hard to get it all the way to the bottom. A solid piece of pipe will tend to point down.


At $1000 every 2 yrs, I would seriously look into a permanent polishing system or something else. While pressure washing the tanks every 2 years is provides a pretty reliable system, unless you have a lot of water or debris introduced, it's probably overkill. If you keep the fuel going in clean and run a polisher periodically, you shouldn't need to power wash your tanks.

[robert sailor]

Originally Posted by Dockhead

Wow, that's a nice looking tank -- Moody? Mine is similar.

Is that permanently installed? Did you put in the dip tube?

Do you have a sump in that tank? Mine has got a kind of sump.

Moody yes but it's a custom SS tank and the tube goes to a low point in the tank. Yes it is permanent, had the tube welded to the inspection panel when I was in Trinidad.

[captain58sailin]

You can always insert a nipple into the end of the hose, or secure a large nut at the end. Emphasis is on secure so you don't end up with it rattling around your tank. I installed a passive centrifuge in my system between the tanks and before the racors and thus far I have not had to change my racors, I drain a dollop off of the centrifuge every so often and so far have not had to change my racors. The centrifuge cost me some $750 US. At $8 per racor, it doesn't take long to pay for itself, not to mention the peace of mind I get from it being there. I had some problems with algae in the tanks and after dosing them with Active X and Power Service over a period of time I seem to have conquered the problem, I'm not getting any particulate from my centrifuge drain anymore just clean fuel. My tanks are not accessible except the sounding tubes and fuel fills, I went to refuel when the prices took a drop and ran Kolor Kut on my sounding sticks, and showed no water contamination, so I am content that my fuel is clean enough to consume. Getting ready for a big trip now and I will change out all of the filters prior to getting underway.

[Juho]

One vote for installing a permanent tube in the tank. With $1000 you can already go quite far. Anything that has its input lower than the current engine input should already help.

I have a manual pump in the engine compartment for taking samples/emptying/checking the fuel. If you plane to sail to some dirty fuel countries or use extra fuel canisters, building a complete fuel cleaning / transfer system would make sense.

[deblen]

Originally Posted by barnakiel

If there is no sump valve to let out some fuel, you take a roughly 4 ft length of hose and tie it to a rod with cable ties. Some 5 mm diameter or thereabouts.

Lock the top of the tube with your finger and force the rod'ed tube to the lowest point of the tank. Remove your finger. Now place the finger firmly against the top of the tube. Draw the sample, investigate.

If you fill the tank twice a year you are unlikely to develop any serious sediment and given normal filters arrangement (prefilter, filter, engine filter) you are not likely to run into any trouble ever. Sure keep eye on those prefilters - that's why it makes sense to have them at hand (ours sit on top of the tanks and we have a A or B selector to switch them without stopping the engine.

b.

Good idea-flexible "pipette"

[a64pilot]

The outboard squeeze bulb will work fine, but unless you have an actual low spot in your tank, little puddles of water will sit in different places on the flat bottom of a tank as there will be several low spots, if you have a flat bottom tank, that is when you want a pump and filter so you can move the tube all over the bottom and suction up any little puddles there might be.
I've never, ever gotten anything in my Racors, I put the dual one on too, but have never had a clogged fuel filter in my life, I guess I'm just lucky, but I have never cruised and fueled in far away places either. I do replace my fuel fill O-ring though, I beleive often that is where water comes from.
My Brother had a boat that had ongoing water issues, I traced that down to a stupidly placed fuel tank vent, once I moved the vent, no more water.


If you have water, where is it coming from? Tanks don't "make" water, now all Diesel has some dissolved water in it, that is unavoidable, but I don't think without a large temp drop it will come out of solution?

[hellosailor]

Dockhead-
In days of old there was a thing called "thieving paste". Damfino if you can still find it under any name. You smeared some on the end of a stick and put the stick in your tank, to the bottom. Then pulled it out. If the paste encountered water, it would turn purple. No batteries required.(G)


While that's not as good as visually inspecting what is in the sump, it certainly is a simple enough procedure, if you can still find a similar paste. Probably in an old commercial "diesel" shop.

[a64pilot]

The paste is till sold, the stuff I had was silver and as you say, turned a bright purple if it hit water.
You "sticked" tanks daily at a gas station to record fuel levels and always put a little of this past on the bottom of the stick

http://www.amazon.com/Gasoila-Regula.../dp/B016ZXZW94