Auxiliary Fuel Tanks - Keep or Remove

[JohnEasley]

Opening this up to the collective wisdom of the group.

We have saddle tanks that hold 600 gallons. We have two currently-unused auxiliary tanks in the lazarette that hold a combined 130 gallons. (The previous owner never used the rear tanks, either.)

We're mulling two options.
1. Reconfigure the auxiliary tank plumbing and install a transfer pump so the rear tank fuel can be transferred to the main tanks for increased range - or -
2. Remove the auxiliary tanks to increase our lazarette storage space.

We burn a fairly conservative 4.6 gallons per hour at 8.5 knots. On just the main saddle tanks, that gives us a range of a little over 1200 miles before we hit a 10% reserve. Perhaps 1150 miles, if running the generator. That's enough range to make it from our home port outside of Tampa, Florida, down to the Keys, up to Biscayne Bay, across to Bimini, over to the Berries, down to Nassau, down to the Exhumas, and all the way back to the Keys before we would be getting close to our 10% reserve. For all practical purposes, isn't that enough range? There is pretty much nowhere we would be going that we would travel 1200 miles without finding a fuel stop.

Wifey is advocating removing the rear tanks so we can recover a lot of storage space in the lazarette. We could use that space to store our folding bikes, scuba gear, etc.

Thoughts? Anything we're overlooking here?

Secondary question: Is there a market for two clean, leak-free 65 gallon fuel tanks?

T'anks. (See what I did there? )

John

 

[Comodave]

I think that I would get rid of them. You certainly have adequate range for coastal cruising.

 

[sunchaser]

Wanderlust.

A counter view-

Keep them under the proviso they are truly usable. Regarding your main tanks - are you 100% sure of fuel volume to empty, I mean sucking air? You can find this sucking air point with a fuel transfer system. Do you have main tank accurate and quantified measuring devices?

Even if a safe 600 gallons, that number seems pretty skinny especially if one goes by the mantra or keeping 1/3 in reserve. Do a really good fuel burn test in rougher water and you will likely find you're down to 1.5 nmpg. Plus once headed offshore it is a real plus to be able to pick your fuel stops.

Last but not least, the next owner may really want the lazarette tanks.

 

[rslifkin]

If we round fuel consumption up to 5gph (1.7 nmpg), figuring less than ideal conditions and assume a safer 25% reserve, that brings range down to just over 750nm. Assuming all of the 130 gallons in the aux tanks can be transferred to the main tanks, that would add another 220nm of range. So it's really a question of whether 750nm is enough or if having the extra would be useful.

 

[RT Firefly]

Greetings,
Mr. MV. Looking at the situation from another angle, where are the bikes and scuba gear stored now? IF you stow that equipment in the laz' are you simply going to fill up the current bike/scuba space with more "stuff"? The question arises, how much "stuff" do you need?



We have "stuff" aboard that might be used once or twice a year but, oh no, we NEED it on board, just in case....

 

[JohnEasley]

the next owner may really want the lazarette tanks.

Which was one of my counterpoints.

 

[JohnEasley]

If we round fuel consumption up to 5gph (1.7 nmpg), figuring less than ideal conditions and assume a safer 25% reserve, that brings range down to just over 750nm. Assuming all of the 130 gallons in the aux tanks can be transferred to the main tanks, that would add another 220nm of range. So it's really a question of whether 750nm is enough or if having the extra would be useful.

Even using those more conservative numbers, we could make it from our home port in west central Florida all the way to Exhumas before hitting reserve. And that's assuming less than ideal conditions the entire way. That's even enough range to make it from North Carolina to Bermuda without being on reserve... if someone were interested in doing that.

 

[JohnEasley]

Looking at the situation from another angle, where are the bikes and scuba gear stored now? IF you stow that equipment in the laz' are you simply going to fill up the current bike/scuba space with more "stuff"? The question arises, how much "stuff" do you need?

Hey RT. Good question that I failed to address in the original post. The scuba gear and the folding bikes are at home in the garage but we intend to bring them with us when we move aboard in April and when we head out for a cruise to the Keys later that month. They'll also be needed when we retire in one year, seven months, and 13 days and start cruising full time. Until now, we've been scratching our heads like a gorilla trying to find an out-of-the-way place to store them.

 

[sunchaser]

Wanderlust
How have you determined your usable fuel load and how do you measure consumption?

 

[JohnEasley]

Wanderlust
How have you determined your usable fuel load and how do you measure consumption?

The previous owner provided the original numbers. We carefully compared speed and time against accurate measurements on the fuel tank sight glass tubes on multiple trips and found that his numbers were within .1 gallons per hour.

 

[O C Diver]

While I lean towards removing the tanks in favor of storage, a useful waypoint might be to fill everything up and see how it impacts trim, etc. That extra thousand pounds of weight might have a very undesirable impact, which could make the choice easy.

Ted

 

[JohnEasley]

While I lean towards removing the tanks in favor of storage, a useful waypoint might be to fill everything up and see how it impacts trim, etc. That extra thousand pounds of weight might have a very undesirable impact, which could make the choice easy.

Ted

There is that point, too. Adding half a ton of weight on the stern would certainly impact the trim. Another point in favor of removing the tanks in favor of storage.

 

[Comodave]

I would not be concerned about what the next owner MIGHT want. What do you want? There is no way to guess what the next owner might want. Do what makes sense for you and your usage. You have enough fuel without the tanks to do any coastal and Bahamas cruising. If you plan to go through the Panama Canal then keep the tanks.

 

[Capitaine R]

How about the condition of the tanks that are in use now. Is there any fear of corrosion that will cause the unused tanks to be needed the future.

 

[Pete Meisinger]

What is your fresh water and black water holding capacity ? Maybe these tanks would be better used to increase one of these storage waters.

Lazarette storage can be like a chest freezer. You pack so much junk on top that you forget what is near the bottom and couldn't get to it anyway. Unless you can access the lazarette from the side or front it is not the best storage.

pete

 

[rgano]

Keep them as water tanks so you can have hollywood showers in the Bahamas!

 

[tiltrider1]

First, pressure test the tanks. Let’s make sure they are good. If not good then you have your answer.

 

[FF]

"The scuba gear and the folding bikes are at home in the garage"


If you have garage storage remove the tanks without damaging them and see how it goes.


You can always re install them.

 

[Chrisjs]

If these are black iron tanks they are no good for fresh or waste water, apart from the fact not that you would never get rid of the residual taste in drinking water. I agree with FF, check them for rust and store them or sell them on Ebay. Disposing of them may not be so simple. They probably qualify as "hazardous waste".