12 Gallon fuel tanks

[45Plus+]

I've gone the 2 x 6 gallon route to replace the 12 gallon on one side of my M. I did it to make hauling gas out to the boat easier. I have not tried to gang the two together yet - there is lots on that topic in this forum though. Time will tell if I find having to switch tanks annoying enough to pipe the two together.

[pitchpolehobie]

I use the 2x6gal tanks and just switch the fuel line as needed to the active tank via a quick connect system. I have them on separate sides to balance weight and have found I prefer that to both on 1 side. To see when I need to switch tanks I use the pick up and jiggle it test. Works fine and less to go wrong.

[dustoff]

I've replaced my plastic tanks twice in 15 years. The UV/Sun is definitely the principal enemy. After the second set delaminated, I installed snap-in sunbrella curtain/shades which has massively extended the life of the plastic tanks (6 years old now and still good). You have to ensure you get the low-profile venting caps to have it fit under the seats.

BWYachts has a really interesting set of custom made aluminum tanks that fit in the same space but hold 17 gallons each. I've been coveting those for some years, but waiting for my current (sun-protected now) plastic tanks to delaminate/fail so as to justify cost.
The additional weight (~61lbs total, 30lbs per tank) I think is a minor concern even with the high Center of Gravity of the fuel tanks. But would be interested to hear from someone who has them.

v/r

[OverEasy]

Hi Dustoff!

Well the aluminum tanks won’t sunbleach that’s for sure!
At 30 lbs they are bound to be durable I expect too.
I wonder what they cost and if the come in a Mac26X flavor? ( Although I expect my wallet would look a little bleached… )

Best Regards,
Over Easy

[ris]

I think Chinook has those 17 gallon tanks. It might be somebody else. I will try to get hold of Mike.

[dustoff]

I looked at them again. They're 16 gallon tanks. Figure the tanks weigh about 10lbs each more than standard poly 12 gallon tanks, and carry 4 more gallons each of fuel at 6lbs per galloon. So completely full of fuel total weight would be about 70lbs more than full 12 gallon moeller tanks. Not a big deal by itself, but ounces add up to pounds etc. Each little modification I've done always adds a bit of weight and another 70lbs is something to consider. I've added 32 gallon fresh water tank & pump, grill and stove, swim platform, sterns seats, canvas package, head, electronics, rigging and sail control improvements, etc. I haven't come anywhere near to Highlander's weight increase, but I'm guessing I've added 3-400 lbs to base weight of the M. I'm Just considering the impacts. In a way, I've probably reduced the # of passengers I should take to stay within safety margins when fully loaded with water & fuel. With my aging ETEC 60 and the ballast in i'm already topped out in motoring speed to 14 knots when loaded for an overnight trip.

[OverEasy]

Hi DustOff!

Thanks for mentioning the “just one more thing” weight syndrome!

Things do add up!
I recently noticed that our ‘boat backpack’ that we carry to/from the boat seemed to be heavier this season… I initially thought it was just my getting used to it again…. Then curious I emptied it out and found all those ‘little things’ it had been accumulating… 2 bottles of sunscreen, an extra set of glasses, a ‘spare’ binocular, a roll of laundry quarters…. Etc… about 8 lbs worth in all!
That’s equal to a gallon of water!

I had a good laugh and got things pared down.

So the aspect of adding weight to the boat is a similar aspect that needs to be addressed too!
I recently went through the onboard bins at start of season paring down and reorganizing. I moved all the ‘carried’ boat hardware (junk drawer) stuff from the baskets to a lidded bin. It was humorous to see all the ‘good junk’ I’d been lugging around as an ‘I might need that someday’! Most of that stuff is now on a shelf in the garage where it belongs…about 15 lbs worth alone…. Never mind all the other stuff that I didn’t put back in the boat for this season (given the change in cruising plans due to the radical economics aspects we are facing of late).
Oh well…

At one time we’d considered adding an additional 5 gallons worth of fuel capacity above our existing 24 gallons but that would have entailed mounting to the stern rail which is pretty high off the water line… it really wasn’t worth it at this time for us… slower engine speed gives us the additional range.

Best Regards
Over Easy

[45Plus+]

I should have mentioned in my previous post that my two 6 gallon tanks are Scepter - low profile, under seat types. They fit just fine, fuel cap and all. The only thing I do not like about them is the fuel line connection point is not in the center of the tank - it is well off to the side. This means my fuel hose sticks out a bit more into the cockpit before turning and running back to the engine. It was nicer to have that fitting on the center of the original tanks so the fuel hose could be snaked through the gas tank cubbies and only pop out well aft. Something to consider. I will be having to remind people to watch out for the fuel hose while motoring. While sailing, I think I will disconnect the hose at the tank and loop it around the fuel filter/water separator located in the motor well area until the motor is needed again. I also checked to see if I could reverse the position of the tank so the fitting is on the outboard side of the cubby but there is not enough clearance to connect the fuel line (too bad....).

I still have one of the original 12 gallon tanks on one side. It is showing sun damage on exposed surfaces - mostly just the outer upper corner of the tank. The sunbrella curtain idea makes sense for this tank but as mentioned above, the way the fuel line connects to the new 6 gallon tanks (ie sticking out into the cockpit a bit) might preclude that idea (unless I use a baggy curtain or only install it when the boat is not being used (ie the fuel line disconnected).

As a related aside, while replacing fuel tanks, hoses, filters etc I also replaced the male and female hose connectors. I was disappointed to see two of the new fitting I put on my new and old tanks leak gas when the tank was under pressure (from the sun) or when the tank was tipped up to flood the end of the tank where the fitting is located. Obviously the little pins in the connectors were not sitting properly on the o rings in the fitting. Both the tipping and heat build up pressure should have firmly set the pins against the o rings and stopped any leakage. And these were supposed to be higher quality, all metal, fittings from a marine supply store as opposed to Amazon. Go figure. Good thing I was around to see the pressure related leakage. Who knows how much gas might have been forced out of the tank into the fuel tank cubby.

[dlandersson]

Ditto. Except my tanks are both one the starboard side.

I use the 2x6gal tanks and just switch the fuel line as needed to the active tank via a quick connect system. I have them on separate sides to balance weight and have found I prefer that to both on 1 side. To see when I need to switch tanks I use the pick up and jiggle it test. Works fine and less to go wrong.

[dlandersson]

Ditto. It's irritating, but not a big deal.

I should have mentioned in my previous post that my two 6 gallon tanks are Scepter - low profile, under seat types. They fit just fine, fuel cap and all. The only thing I do not like about them is the fuel line connection point is not in the center of the tank - it is well off to the side. This means my fuel hose sticks out a bit more into the cockpit before turning and running back to the engine.

[LordElsinore]

BOAT had those aluminum tanks and said he really liked them. He's posted about them on here before. Sadly he's no longer a Mac owner and hasn't been on here for a while. I've been eyeing those for a while, though there is a battery grounding wire you are supposed to attach as well so keep that in mind (probably a hole or through-bolt of some kind needed)

I ordered 2 12 gallon Moeller tanks 3 years ago off Amazon, even though the BWY site claimed that the newer tanks weren't the right size. They fit just right as replacements for my faded originals

Here's a link to the ones I bought. They've gone up $20 since I bought mine:

https://amzn.to/3Gr4bTS

[Russ]

BOAT had those aluminum tanks and said he really liked them. He's posted about them on here before. Sadly he's no longer a Mac owner and hasn't been on here for a while.

Here's a link to the ones I bought. They've gone up $20 since I bought mine:

https://amzn.to/3Gr4bTS

BOAT doesn't own his Mac anymore? Wow. He had some great mods. Very professional.

Thanks for the link to the tanks. Mine or original and getting kind of old. I was worried the new tanks would not fit.

[OverEasy]

Hi 45Plus!

. And these were supposed to be higher quality, all metal, fittings from a marine supply store as opposed to Amazon. Go figure. Good thing I was around to see the pressure related leakage. Who knows how much gas might have been forced out of the tank into the fuel tank cubby.

I appreciate your concerns! We’ve undergone our own issues early on with Quick Disconnects (QDs) not performing as expected.
When we converted Over Easy to two 12 gallon Moeller tanks I gave up on any QDs entirely and went with ‘permanent’ fittings and hoses. I wasn’t concerned with any tank removal issues as there was no way this side of Hades (as I was never gonna lug around a full 12 gallon tank of fuel, never mind two of them! We chose to use the marina refueling option, the fill it at the gas station when it’s on the trailer option, or the manageable 5 gallon tank and a hand cart option. )

The regular brass plumbing fittings and hose were much more streamlined for installation, use and durability. That might be an option for you and your situation or routing desires.

Best Regards, Over Easy