Page 1 of 2

Fuel transfer line

Posted: May 28th, 2020, 11:14 am
by vtcats
This might be a dumb question, but I’m interested in answers from anyone who knows the answer.
My Carver 460 Voyager has a fuel transfer line between the two tanks that sit near the aft of the boat.
There is no pump transfer, it’s simply gravity/pressure I assume. I also assume it’s there because the genset draws fuel on,y from the starboard tank.
So my question is, if the boat naturally lists to one side (maybe not naturally, but due to weight distribution of tender, etc), and I open the transfer line, does the fuel simply move to the lower side of the boat regardless of amount of fuel in each tank, or does this even the tanks out?

Re: Fuel transfer line

Posted: May 28th, 2020, 12:56 pm
by bud37
If it is gravity feed like you say , then the fuel surface will try to be level. Just think water in a measuring cup....tip it up and one side will show more than the other but the liquid will be level. If you are thinking it will level off the boat...it might but only if the tank that is more full is on the low side.....could do the opposite if that more full tank were on the high side.

My take on it anyhow.....now if there was a pump then I believe you could level things off much like ballast tanks in large vessels.

Re: Fuel transfer line

Posted: May 28th, 2020, 1:27 pm
by vtcats
Yes, this makes sense and kind of what I was thinking. Thanks

Re: Fuel transfer line

Posted: May 28th, 2020, 7:53 pm
by g36
I can also feel it will transfer contaminated fuel from one tank to another. Ie. If you ever get water in one then it will now spread to the other. Or debris from whatever. If I had that option I don't know if I would ever use it . I guess i like having my 4 tanks separate. My opinion only. Sure there's good reasons too.

Re: Fuel transfer line

Posted: May 29th, 2020, 12:55 am
by RGrew176
While it's not a gas tank in my case my 3007 has 2 water tanks for the onboard water system. There is a line that runs between the two tanks. It is gravity fed as the level is the same in each tank as water is used up.

Being that I also have two fuel tanks I will have to check to see if there is a fuel leveling line there too.

Re: Fuel transfer line

Posted: May 29th, 2020, 5:15 am
by vtcats
First, I agree about possibly contaminating fuel between tanks if the transfer is used.
Second, I also have a gravity fed line between two 75 gallon water tanks on each side if the boat. I never thought to visually check them. I say, “visually”, because there is one sender that reads total for both tanks.
I pretty much live in my engine room. Can’t believe I never thought of that.

Re: Fuel transfer line

Posted: May 29th, 2020, 6:30 am
by bud37
RGrew176 wrote:Source of the post Being that I also have two fuel tanks I will have to check to see if there is a fuel leveling line there too.


You have a gas boat , so very unlikely.

Re: Fuel transfer line

Posted: May 29th, 2020, 6:51 am
by Viper
Ya you won't have that in your boat Rick unless a previous owner did it. Bad idea to put holes that low in a gasoline tank as leaks there would be explosively dangerous. IMO it's a bad idea in diesel applications too. A leak there won't be an explosion concern but it'll be an environmental one when the bilge pumps kick in. The only way this is safe is to have a transfer pump feeding off the top of the tanks with electric fuel valves with the pump mounted high and an anti-siphon device mounted in the line to prevent siphoning in case of a bad leak.

Re: Fuel transfer line

Posted: May 29th, 2020, 9:16 am
by RGrew176
bud37 wrote:Source of the post
RGrew176 wrote:Source of the post Being that I also have two fuel tanks I will have to check to see if there is a fuel leveling line there too.


You have a gas boat , so very unlikely.


So, it's something that only diesel boats would have. Just curious. Appreciate the information.

Re: Fuel transfer line

Posted: May 29th, 2020, 11:07 am
by bud37
RGrew176 wrote:Source of the post
bud37 wrote:Source of the post
RGrew176 wrote:Source of the post Being that I also have two fuel tanks I will have to check to see if there is a fuel leveling line there too.


You have a gas boat , so very unlikely.


So, it's something that only diesel boats would have. Just curious. Appreciate the information.


I believe so....rules regarding tank fittings are spoken to in the regs...Carver installed that line and isolation valves in his boat ( a diesel ) from the factory, according to the parts diagrams.

You don't want to find that type of system on your gas boat...IMO... :-O