Diesel tank baffling

[ptg 0]

Hi all, after air locking the donk in some moderate swell after fuel in the 1/4 full tank sloshed away from the pickup, have come to the conclusion we need to retrofit some form of baffling. The tank is fibreglass built into one of the cockpit lockers, about 80 litres with a central 90mm filler/access port, currently it has no baffling.

 

Have heard of a type of open cell foam you can stuff into the tank to act as a baffle, any one know anything about this, where to get it etc ? Or any other ideas/suggestions.

 

Thanks

[wheels 543]

It's a specialised metal material they use in Race cars to stop explosions of the fuel tanks. I expect you might find it at a Race car parts supplier. Perhaps try Cardwells. But you are going to have to remove the entire top of the tank and place it in. It's rigid. There is no pour in foam material if that is what you were thinking. So if you are going to take the lid off the tank, I would suggest you just fit fibreglass baffles. Of course the fact you ran out of fuel may not be due to sloshing, but maybe due to the tank being on such an angle that the fuel line went dry. Baffles will not stop that happening.

Or another popular idea is a "day tank". It's a small tank that will give you several hrs of motoring and placed near the engine. You simply pump across enough fuel to fill the small tank to get you through the Days motoring. You can use a pump or install the tank so as you can use gravity.

[too_tall 15]

Or even just fit a "surge tank" such as a lot of race cars now have - you feed this small, conical shaped tank ( so it always drains nicely ) with an electric pump or two ( one port suction, one starboard suction ) and then no matter what is happening, you will always have a supply of fuel to the engine. Bearing in mind that these surge tanks often hold 4 - 5 liters, that should be enough to keep the boat operating for quite some considerable time if you really have issues with the diesel slopping around in the main tank.

[ptg 0]

Cheers guys, yeah I had considered a surge tank type setup (more familiar with cars than this marine stuff ) tho currently just trying to work from the simplest solution toward the more complex.

 

The foam stuff I have seen appears to be like a fuel resistant foam rubber that can be squashed through the opening in blocks to fill the tank, seen it online but was curious if it is commonly used or available locally. Though comments above regarding the angle I think may have some substance.

 

But lots of good info/ideas thanks.

[too_tall 15]

If you can have a port and starboard suction, and mount the fuel pump below this ( with reasonably large diameter fuel lines ) you should fix up any issues if its related to heeling. Even if its for-aft pitching, you should still get a good solid flow this way. If that fails - surge tank...

[rigger 47]

there are baffle balls you can get -

 

http://www.nrfa.org.nz/Operational%20do ... System.pdf

 

http://www.promaxplastics.co.nz/product ... ystem.aspx

 

the above might be a bit big.

[wheels 543]

One other thought is to use a Fuel Bladder.

[too_tall 15]

there are baffle balls you can get.

 

Those are interestingly named. But look as if they would do the job of adding baffles very well.

[PaulR 3]

+1

 

Most interesting apart from the size that may be just tooooooo BIG for a small yacht.

 

 

What about those small practice golf balls.

 

A clever chap like you may be able to fit them down the 90mm filler hose pipe (what bends or elbows??), and then wash down with a splash of diesel as well!!.

 

 

No disassembly required + not that many required = low cost solution.

 

You may only need about 20% to 33.3% volume of tank. The balls may "float" in the diesel and whilst they may stop a lot of "top" slosh when the tank is full, BUT in your case, when the tank is down to 25% full, the balls will then be "sitting" on the base of the tank as a more rigid structure and act as "desirable" baffles.

 

It seems so simple really.

 

I, and no doubt others, will be most interested in your results. or the price of plastic practice golf balls will universally sky rocket.

 

 

Once upon a time, as all good stories start, fitting out a 65ft high speed luxury motor boat (think commander in chief very fast gun ship) the double-DOUBLE grunter down in aft state cabin could take 3,000+ gallons of fuel. We fitted the same alloy mesh as used in Harrier jump jets fuel tanks, which took up 2% volume but you could fire HE rounds in to a say 44gal drum and whilst the fuel may leak out, it did not explode.

[wheels 543]

Not saying the practice golfball's wouldn't work, but just be weary that some plastics won't like Diesel for extended periods of time. It may likely become weak and brittle and break down and then become a problem.

[ptg 0]

Some great ideas here

 

Yeah had looked at the baffle balls but did wonder if they were bit on the large side, but practice golf balls now we're thinking! Think some testing may be required, and yeah will be sure to check fuel resistance etc, the thought of removing half dissolved warehouse golf balls from fuel line doesn't sound like a fun way to spend a weekend lol.

 

Fix for the moment has been to carry enough fuel to keep the tank topped up, but will be sure to update when we get a more permanent solution.

[wheels 543]

Be aware, you may not see any issue with Plastic till maybe 12mnths or more down the road. It usually becomes brittle and weak and would break up into tiny bits