Fuel Tanks.

Hi guys whats the score with Plastic fuel tanks are they custom made or are they off the shelf and you make fit.

Any advice please

 

Both, depends on what you want. Look up Moeller, Todd, Sceptre. I think there's a few other mfgrs.

 

cheer's M8 just what I was looking for, do you know if they are linkable say 3 or 4 in series ?

cheers

 

Just got one delivered from Moeller today. It was actually a model from the Tempo line that Moeller recently took over. If you want anything rather than off the shelf, you will need to make a large order since they are made in large batches. That is, unless you don't care how much it costs.

Marine tanks are vented to the atmosphere so I don't think you could set them up in tandem. You will need a transfer valve.

 

I've seen two tanks hooked in series from side to side.



This one was build in Australia. I don't know what their standards or certifying bodies have to say about the practice though.

 

id have put a valve at each end of the intercostal

 

ATL - makes custom rotor molded gas tank's that have baffles and i just started a thread on a 32 Skater which will show pics of the work on the boat ( repairs ) and the process that is involved in doing the repairs on the gas tanks on an epoxy boat .

 

Connections between tanks have different regulations if they are gas(petrol) or diesel.

 

Of course fuel tanks can be connected in series if the connection is at the bottom of each tank. That may not meet USCG regulations and certainly does not meet mine. There is a reason fuel outlets are taken from the top of the tank.

From USCG Safety Standards for Backyard Builders: COMDTPUB P16762.3B
"Each fuel line from the fuel tank to the fuel inlet on the carburetor must be above the level of the tank top or have an anti-siphon device or electrically operated fuel stop valve."

Open to some interpretation, but the phrase anti-siphon means that the fuel line must not even dip below the level of the tank top without anti-siphon protection. Not said but strongly implied, at least to me, is that all outlets must/should be from the tank top.

That photo looks like a death trap to me. Think of what the consequence of a leak at the connections between the tanks means. Other interpretations may vary but the set-up in the photo also needs anti-siphon protection because the fuel in the tank is always above the engine fuel inlet.

 

As Tom pointed out, the USCG won't certify such an installation, and it also goes against the recommendations of the ABYC.

The main reason for this is in the event of failure, you have no way to keep all that fuel from leaking out into the bilge, which the presents a huge fire and health hazard. This would also be the logic behind having the fittings in or near the top of the tank.

 

I am just informed that Australia has adopted the ABYC standards.

Gravity feed fuel systems used to be common, but no more. That includes the old common small day tank that was hand pumped from the lower main tank each day and gravity fed to the engine.

 

Ok, while I've got your attention. I really didn't see that joining two tanks at the bottom as in the picture was all that wise, prudent, safe etc. I can't comment on what thinking went into that system but the builder seemed to be comfortable with it. For the record, it's a diesel boat.

Anyhow I was thinking of a way to accomplish something similar with twin tanks. I found a diesel fuel return valve that'll dist. an even amount of fuel to two tanks. It's used on large diesel trucks to return fuel to the twin outboard tanks. I'll post the link when I find it.....

Anywho, here was my idea, much like a "water level" where a siphon maintained between the two tanks would constantly adjust the level of the two tanks.



The idea is to use a fairly small connection between the two tanks, 1/2" or so. This'll prevent too much fuel from moving from one tank to the other in a situation where the boat might have taken on a list or something. There'd be a small valve at the top to induce the siphon. Ever siphoned gas? You get the idea.

Thoughts?

 

Gents sorry too say, but this is outright flippen stooopid and very dangerous.

The plastic "nipple" on the tank WILL eventually break out with fatigue and vibration of the weight of the hose.

The nipples as outlets should have a ball valve on it for emergency shut off and service - AND the hose MUST BE SUPPORTED properly

not good not good - oh deary me

 

Just another reason why you need 12 pairs of eyes when you buy used boats built by experts and surveyed by professional salesmen, by the time that you have stripped and checked everything it could cost a fortune, bad news really.

 

Oh no i am going potty

gents when i zoooom in on that pic

doesnt it say suitable for AIR AND WATER ie Airhose?

farkit i hope i am wrong