converting to single point refueling on Tolly 44

[Tollylover]

Hi everybody,
I will be starting the gas to diesel repower of my '88 44cmy in December. Part of the job is to get new aluminum tanks built. Has anyone heard of plumbing the tanks to a single point refueling system to eliminate the need to reposition at the fuel dock or drag the hose a long way to reach the other filler neck. The yard is talking of a 2" balance tube, I'm not crazy about a 2" line coming out of the bottom of both tanks and crossing the entire beam of the engine room, too much chance of leaks, murphy's law being what it is. I'm thinking transfer pump. any ideas?

 

[mvweebles]

2-inch sounds about right given hi-flow fuel docks these days.

But I have to ask, what's the problem with having dual fill inlets? It's common and has worked well for 100 years. I would have a nice central manifold with supply and return valves along with a transfer pump and a smaller fuel pump to prime engines. Here's mine for a single engine dual tank.

One of the things I wish I had done different when I redid my tanks is put the fill inlets on the sidewalk of the cabin vs the deck. Pretty well guarantees no water leaks into fuel tanks. Also, make sure the vents are oversized and have a nice loop on them to keep water out.

Peter

 

[Comodave]

We have 2 tanks, one on each side. It isn’t that bad taking the hose across the cockpit to fuel the offside tank. I think it is better than a transfer pump. That will get old waiting on the fuel to transfer while refueling. Unless you put in a huge transfer pump.

 

[slowgoesit]

I second what Dave above said. Waiting to transfer from one side to another, while tying up the fuel dock for an extended amount of time won't make you any friends with either the fuel dock, or the people waiting to fuel!

 

[Delta Riverat]

I'd go with 2 fills also.

I don't like the 2 inch crossover and I don't like having to wait for the transfer pump to keep up or (worse yet) too fast so the fuel goes on the deck or the drink from the side I'm not watching.

 

[Comodave]

We have oil absorbing pads aboard and when we move to the farside fill we just wrap the nozzle in the pad to catch any drips. Pretty easy.

 

[ksanders]

Hi everybody,
I will be starting the gas to diesel repower of my '88 44cmy in December. Part of the job is to get new aluminum tanks built. Has anyone heard of plumbing the tanks to a single point refueling system to eliminate the need to reposition at the fuel dock or drag the hose a long way to reach the other filler neck. The yard is talking of a 2" balance tube, I'm not crazy about a 2" line coming out of the bottom of both tanks and crossing the entire beam of the engine room, too much chance of leaks, murphy's law being what it is. I'm thinking transfer pump. any ideas?

Easy peasy

simply install a transfer pump between the two tanks.

That's what my Bayliner has from the factory.

 

[Ken E.]

I have port and stbd fills for their respective tanks. I don't mind pulling the hose across...sometimes simple is better and ultimately easier.

 

[rslifkin]

My fills are in the aft deck right at the transom corners. Bringing a hose to the other side has never been much of a pain point. Plus, we often get 2 hoses when possible so we can fill both tanks at the same time and be done faster. If the fills were midship on the sides then I could see wanting a way to fill both from one side.

 

[KnotYet]

My last boat had a 2" transfer pipe between the 2-175 gallon tanks & 2 deck fills.
The pipe incorporated a ball valve in case you wanted to isolate the tanks.
The transfer pipe ran along a bulkhead so it was protected and not obtrusive.

There was a lot of deckhouse between the fills so it was a convenience for fueling.
It connected the tops of the tanks so was more useful for filling, not balancing.
No down side, really.

 

[Delta Riverat]

Top of the tanks wouldn't scare me so much. No chance of draining 300 gallons of diesel into the bilge.

 

[Comodave]

Maybe a 3 way valve on the fill line. Switch to one tank and fill it and then switch to the other tank and fill it.

 

[psneeld]

The yard may be suggesting a crossover tube because they aren't all that uncommon.

The older Sea Ray 54's would have been difficult to run a fuel dock hose to both sides. I think their crossover was way bigger than 2 inches. Never heard of problems with those. Proper install and very little maintenance should insure nothing more than a tiny, rare nuisance leak.

If not a crossover at the bottom of the tanks, a line from one side to the other like others suggested is a better option than a transfer pump given fill flow rates.

 

[Retriever]

The boat I’m on right now is the easiest boat to add fuel that I’ve run. Several things factor into this, some of which might be applicable to your situation.

1. Camlock inlet to fuel manifold…no burps, no leaks, but you better be sure your venting is up to the task.
2. Sight guages in view from manifold. From the ER it’s easy to open/close valves to each tank as they fill. I usually start fueling with all the tanks open. They fill at different rates and I can use the valves on the manifold to “throttle” the rate to each tank.
3. Large vents with threaded fittings. When fueling, screw in a hose to each vent that is directed into a bucket. Any overflow is contained.

 

[rslifkin]

The boat I’m on right now is the easiest boat to add fuel that I’ve run. Several things factor into this, some of which might be applicable to your situation.

1. Camlock inlet to fuel manifold…no burps, no leaks, but you better be sure your venting is up to the task.
2. Sight guages in view from manifold. From the ER it’s easy to open/close valves to each tank as they fill. I usually start fueling with all the tanks open. They fill at different rates and I can use the valves on the manifold to “throttle” the rate to each tank.
3. Large vents with threaded fittings. When fueling, screw in a hose to each vent that is directed into a bucket. Any overflow is contained.

That sounds like it was designed by someone that's used to fueling airliners. Out of curiosity, how many fuel docks can readily accommodate the cam lock connection rather than sticking a nozzle in a hole?

 

[Hippocampus]

Agree the more fills the better. When filling will shut the cross over for awhile to make sure new fuel is good. Then open it after running for a few hours on one tank. That way have the option of polishing one tank and using it until next port of call and cleaning all the fuel.
My last sailboat had four fuel tanks . Topping off just before passage one got contaminated. Could isolate that one and just not use it until after landfall and it could get cleaned. Three boats ago had 2 fuel tanks but freezer and frig were on the same side along with the pantry and galley lockers. Would trim using the fuel tanks. Once we ate and drank enough would open the crossover. I suppose you could trim closing fuel returns but it’s easier when filling up.

 

[DennisB1]

Typical refuel rates from a diesel hose is in the area of 10 gpm and with a larger nozzle where commercial boats refuel is in the area of 20 gpm where I have refueled my boat. To make fueling two separate tanks with an interconnected balance line work for gravity flow requires establishing a head difference between the two tanks (inches of fuel above the receiving tank). This requires understanding the maximum refuel rate required for refuel, the required inches of head for transfer to the interconnecting line. For example using gravity transfer only, if transferring 10 gallons/minute might require a difference of 10 inches of fuel height to achieve the required flow rate of 5 gpm to tank A and 5 gpm to tank b. So, the question is with 10 inches of head what flow you can get with about .3 psi driving head pressure. This requires the understanding of the pressure calculation to determine losses thru entrance and exits, thru valves, bend angles and line length and pipe or tubing roughness for each planned size of plumbing. With a 2 inch line flow rates up to about 200 gpm were used with a transfer pump for refueling tanks on the airplanes that I worked on.

Big problems are concerns about shutting off the flow to prevent fuel spillage into the surrounding water.

With a standard over port nozzle, visual observation should alert the refueler to shut off flow and wait for the tank level to drop before resuming the fuel flow.

If you were to use a pressure fueling nozzle connection as used in larger airplanes would require several levels of automated shutoff valves to provide more than one level of protection and shutoff to prevent spillage- same would be required for a boat.

From a safety standpoint and keeping the solution simple, separate fill points would be the best option IMHO.

I have on my boat a 3/8 inch ID line between two 500 gal tanks which I close when refueling the tanks that allows me to fill to full then move to the second tank to fill to full without going back to the first tank to top off. Even though the line is small, the first tank can back flow 10 to 15 gallons if the balance line is open.

 

[SIBERNUT]

If it were up to me I'd cut a second fill into the deck and run a rated hose across the overhead to the other tank. Safe. Minimal work & $.
Wanna get fancy put labels on side of house.

 

[BruceK]

2 fills, one per tank works for us. We open a window both sides and pass the filler hose through to fill the far side tank.

 

[Mako]

OP, since you're pulling the engines and tanks, can you convert to a single tank? Perhaps reorganize your ER so the tank sits athwartship at the bulkhead. A single wide, skinny tank. Then you can add a 12hr day tank which would gravity feed your engines.

 

[RickyD]

I believe I have a similar question that may indicate a venting problem for fueling two tanks from one inlet. At the risk of Hi-jack, I replaced my 265 gallon centerline tank and it required 4 segments now holding 250. The fill enters the aft segment where the vent line is as well. It takes "FOREVER" to fill because of the time for the fuel to run forward and the air to run aft and out. My buddy has a similar set up and he had a dipstick installed in the center tank. When filling he attaches a vent hose to the dipstick point and gets additional venting there making it much easier to fill. I'm thinking about venting each segment into a manifold and then enlarging the vent overboard to achieve easier filling. How does that sound to my expert audience?

 

[Comodave]

I believe I have a similar question that may indicate a venting problem for fueling two tanks from one inlet. At the risk of Hi-jack, I replaced my 265 gallon centerline tank and it required 4 segments now holding 250. The fill enters the aft segment where the vent line is as well. It takes "FOREVER" to fill because of the time for the fuel to run forward and the air to run aft and out. My buddy has a similar set up and he had a dipstick installed in the center tank. When filling he attaches a vent hose to the dipstick point and gets additional venting there making it much easier to fill. I'm thinking about venting each segment into a manifold and then enlarging the vent overboard to achieve easier filling. How does that sound to my expert audience?

Are you able to add vents to the tanks? If you are I am sure it would help speed things up. On a previous boat we had a custom 600 gallon fiberglass tank made. We had 2 oversized vents, one to each side installed. Also had a large filler put in to accommodate the high speed pumps at commercial fuel docks.

 

[IWAB]

Fuel arrangement

I think I may have an overly simplified arrangement which I maybe should upgrade? My GB EU has 4 fuel tanks. Two each side. Only the two forward tanks on each side are used for fuel return and supply. The other two, aft of the first two, are connected to the fwd. tank(s) via a 1-1/2” fuel line. Also there is a cross connect a 1-1/2” fuel line with a Groco ball valve.

I have no manifold. Each forward pair on each side supply and return fuel to its corresponding engines.

The tanks are aluminum and are not the original tanks. Comments from readers? There are electric fuel pumps on both port and stbd.

Is it too simple a setup? So far I’ve had no problems.

 

[IWAB]

I forgot, all fuel tanks are valved at their bottoms.

Alex

 

[Comodave]

I think I may have an overly simplified arrangement which I maybe should upgrade? My GB EU has 4 fuel tanks. Two each side. Only the two forward tanks on each side are used for fuel return and supply. The other two, aft of the first two, are connected to the fwd. tank(s) via a 1-1/2” fuel line. Also there is a cross connect a 1-1/2” fuel line with a Groco ball valve.

I have no manifold. Each forward pair on each side supply and return fuel to its corresponding engines.

The tanks are aluminum and are not the original tanks. Comments from readers? There are electric fuel pumps on both port and stbd.

Is it too simple a setup? So far I’ve had no problems.

What is wrong with simple? Nothing.

 

[Circumnavigator]

I am a strong believer in having a day tank. Having one, you know that you have a day's fuel that has been filtered once. Even if you have parallel filters, a load of bad fuel will cause a shut down -- sure, you can fix it by throwing two valves, but shutdowns like that always occur without warning at the worst possible moment. I've had them on our last three boats and will install one on the next boat if necessary.



I'd be nervous about filling two tanks at once -- odd things can happen and I can image the tank on the opposite side becoming full first and spitting out its vent.


Fintry has a single 3" fill pipe with a cam lock and valves to select one (or more) of the four bottom tanks. At the fuel dock in Boston we took 75 gallons a minute, which is nice when you carry 5,000 gallons. Larger vessels do not have automatic shutoffs -- you tell the fuel person how much and they dial it into the pump. If we wanted to get Fintry dead full (leaving space for expansion if needed) we had to top off three tanks with the transfer pump from the fourth and then very carefully top off the last one from the dock.


Jim

 

[Goody]

Sorry for asking this, but are your fuel fittings on the deck or on the side of the hull. My gas powered Tolly has them on the side (at a bit of an upward angle) so refueling it from just one side is a bit of a hassle so having a single fuel inlet would have a certain amount of appeal (but not possible for a gas boat), especially at a busy marina. Nobody likes to get stares from other boaters. Besides the risk of spillage into the marina water during fueling while hanging over the edge.
I don't like the idea of a transfer pump either since a pump failure will result in unexpected problems and being Murphy's law always being in play will happen at the worst time... so things will just go from bad to worse... or maybe it is just me.

 

[Tollylover]

Hi Goody, My Gas Tolly 44 fuel fittings were the same as yours. I am in the process of repowering with Cummins diesels, including new fuel tanks. We are not using any type of single point or transfer system, due to the potential for Murphy to show up! these great boats have been around for a long time so I guess we deal with the two fill system , and let the other fuel dock folks wait. It has been my experience it is the guy with the 17ft outboard with a whopping 20 gallon tank that will fuss the loudest. I'm sure the fuel dealer would much rather have your 300 tanks visit him! Enjoy your Tolly as much as you can, I have learned so much about the construction of the 44 during the repower, and have even more respect for how well they are built. The hull is a Tank!! smooth running.





























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