Ponderosa fuel filling ports

I recently purchased a 1986 Ponderosa 42 Sundeck and am confused by the 4 fuel ports on the deck: two on each side, one on the main deck at midship and the other on the step to the aft deck. When I added fuel through the lower port there was no apparent change in the fuel level in the sight tube; switching to the higher port produced an immediate increase in the fuel level. I assume these two ports feed into the same tank but don’t know why the level in the sight tube only reflected fuel added into the higher port. Can anyone explain what the two ports feed into?

Well, since you don't smell fuel throughout the boat, the fuel you put in the lower port must have gone into a tank someplace. Since the fuel level did not rise on the sight tube you were watching, I think you must have other tanks that you haven't found yet.


Are you sure you didn't put fuel in either the waste tank or the water tank?



Ken

No fumes, no fuel to other tanks. Measuring the fuel tank dimensions indicates it is about 200 gallons. The sight tube read 1/2 full at the outset; adding 40 gallons to lower port didn’t move the level; adding 60 gallons to upper port filled the tank!

I would dig into the boat and follow that aft hose. What we do know is the fuel is not going to the tank with the sight tube. The builder would not have put two fillers to the same tank. You need to find the second tank and then you need to find out how the fuel gets to the engines from that tank.

I had a Uniflite 42 once that had a decommissioned belly tank. Fortunately I noticed a capped fuel line in the engine room that I traced to the belly tank. Then traced the filler to the aft quarter were I promptly installed a locking fuel cap to prevent a future error.

rbigsby said:

Measuring the fuel tank dimensions indicates it is about 200 gallons. The sight tube read 1/2 full at the outset; adding 40 gallons to lower port didn’t move the level; adding 60 gallons to upper port filled the tank!

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We also can surmise that adding 60 gallons to a 1/2 full 200 gallon tank won't fill it. So either 1) it's not 200 gallons, 2) your gauge is wrong and it was either not half full or it's not full now, 3) the tank is not regularly shaped and is tapered toward the top, 4) you got a good deal at the pump because you paid for 60 gallons but they gave you 100.

I agree with the comment to trace the lines, as painful as that may be. It's just too important with fuel to know where everything is and what fills what.

From a friend with the same boat. 4 tanks of 125 gal each, each with its own filler port. 2 tanks on port side with a sight glass, and 2 tanks on starboard side with a sight glass.

Thanks all. “Digging into the boat” is easier said than done. I’d rather not tear apart the structure surrounding the tank(s).

Special thanks to the friend of PORMAN. It would appear that both tanks on one side are connected via 3/8 inch line that runs along the bottom and it probably just takes time for the sight tube (which is on the aft-ward tank) to register filling of the forward tank.

Digging into the boat is necessary to learn how the boat is built and how it works. It may be a bit painful but you should poke into every area of the boat. The time to figure out how it is built isn’t when you have an emergency. If indeed you do have 4 tanks and if you have 4 fillers it is almost certain that you do have 4, then you need to learn how the fuel system is configured so you are able to switch between tanks.