T&T: Fuel manifolds

[Albin43SDtr]

Robin and All,

>I've been meaning to ask a related question here for a long time: For twin
>engine installations using a common fuel supply manifold, what are the
>manufacturers recommendations on use? Can you in fact draw fuel from multiple
>tanks simultaneously??

I can't say anything about what the manufacturer - Albin - 
recommended as there was nothing in the literature I received with 
the boat. The Celestial has a fuel manifold which has six valves - 
three inlelt valves from the two main tanks and one from the 
centerline tank; and three outlet valves to the two engines and one 
to the generator - each has its own Racor fuel filter.

In use, the engines draw fuel from the least resistant side, i.e., 
the one with the highest fuel level. In actuality, provided there is 
no air in the lines to preclude siphoning (a common problem when 
messing with the fuel lines :-) ), the fuel in the two saddle tanks 
will equalize quite rapidly. After replumbing the boat and installing 
the fuel polisher, I experimented with fuel draw. I was curious about 
stability and wanted to know if fuel could/would flow from one side 
to the other and in doing so, cause a dangerous list. The answer to 
creating a dangerous list was - NO - the tanks would equalize on 
their own, putting the boat back into trim. I pumped (using the new 
polisher) one tank dry, putting the fuel into the opposite side. This 
almost filled that tank, and caused about a 10 (?) degree list. I 
then pumped all the fuel into the opposite tank, thus polishing 100% 
of the fuel in two (?quick?) passes. When all of the fuel had been 
pumped/polished, I shut off the polisher and opened the fuel valves 
on the manifold. The fuel immediately started to run to the 
opposite/empty tank. I then opened the crossover valves and closed 
one fuel tank valve on the manifold. The tanks continued to equalize. 
I then opened all the valves and that simply sped up the process. The 
boat also remains in trim with full tanks and the manifold valves 
open, as that is how the valves were placed when we first bought the 
Celestial. The Celestial has very good lateral stability as evidenced 
by this test. We have seen evidence of this on other occasions as well.

In short, the manifold simply helps to keep the Celestial in trim 
when the two main tank valves are open by keeping the tank levels 
equal. Boats with less natural stability could have dramatically 
different results....

Just my observations, YMMV.


Take care and be safe.

Wayne
Celestial
Albin 43 Sundeck
Near Panama City, FL