How to Measure Your Tank

Before you place an order, make sure your tank will actually fit.

All tanks are built to the exact dimensions you provide. We do not guess, assume, or adjust your measurements. If your tank doesn’t fit, it's very likely because the measurements you submitted weren't correct.

By checking the agreement box at checkout, you’re confirming you’ve read and followed these instructions.

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Important: What Your Measurements Should be

The dimensions you enter into the quote form must reflect the main body of the tank ONLY.

Do not factor anything else into the tank body dimension:

• Filler neck height

• Vent Pipe height

• Fitting height

• Mounting tab dimensions

• Clearance or obstruction space

These extras listed above are some examples of what are accounted for separately in our system. Entering inflated or incorrect numbers will throw off your quote and almost always lead to fabrication and fitment issues.

We need your raw tank body dimensions — just the shell — in order to generate the most accurate price and build plan possible.

 

General Rules for Measuring

Keep in mind: filler necks and vent pipes will typically add 2.5–3 inches of height above your entered tank height. If you are building within a tight overhead space (under a deck lid, floor, etc.), be sure to factor in this additional height so the tank will still fit once fittings are installed.

• Always measure in inches

• Use a good tape measure, not a photo, another estimate, or an old tank

• Do not measure your old tank unless you're 100% certain it fits your space correctly with room to spare and is not touching or rubbing anything.

• Leave at least 1/4" clearance on all sides: top, bottom, ends, and sides

• Account for:

  • Deck lids / access hatches

  • Sloped floors or bulkheads

  • Stringers, cross-bracing, or brackets

  • Hoses, wires, or fuel line routing

  • Mounting tabs (they add width/height depending on placement)

  • Inspection clearance if you ever plan to remove the tank

If your tank has to slide in at an angle, make sure it will actually clear the opening while being installed. If it's tight — go smaller.

 

Key Dimensions We Need

 Length, end-to-end, the longest dimension of the tank

Width, side to side when looking from above

Height, bottom to top of tank body (do not include filler neck)

Filler Neck Height, we add this separately — you do not include it

If you're ordering a tapered, belly, v-bottom, or port/starboard shape — you'll also need to provide secondary width and height numbers. These are all handled on the quote page.

 

Mounting Tabs

If you're adding mounting tabs, they must be accounted for outside of your tank dimensions.

• Standard flat tabs add roughly 1 1/4" of width (on each side) or height depending on where they're placed

• Heavy-duty angle tabs add closer to 2" (per side)

• We do not pre-drill tabs — you install as needed

• You must clearly show tab location & tab length on your drawing

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Mockup Tanks (Cardboard vs. Plywood)

We’ve seen a lot of customers try to mockup a tank out of taped-together cardboard and cram it into a tight space to check fitment. While the idea seems smart, cardboard bends, compresses, and flexes. An aluminum tank does not.

If your cardboard mockup fit, it likely did so because it deformed to squeeze into the space. Your actual tank will not do that.

If you're serious about mocking up a tank before placing an order, we strongly suggest building the mockup out of thicker plywood with rigid corners. This will better represent how the finished aluminum tank will behave during install.

If you're even considering using cardboard, we recommend reviewing our Return Policy before moving forward — and reconsider using plywood.

 

Common Mistakes to Avoid

• “I measured the old tank, not the space.”
  → Bad move. Old tanks swell, warp, or weren’t a great fit to begin with.

• “I forgot to subtract for mounting tabs.”
  → Tabs take up space. If your tank is tight, you must allow room for tabs.

• “I didn’t think about the lid or deck.”
  → Clearance is everything. If you can’t get it in, it doesn’t matter how well it’s built.

• “I assumed you’d call me if something looked off.”
  → We don’t guess. If something's unclear, we won’t build it until we confirm with you. But if your specs are wrong and we build it as-is, that’s not our fault. Be as descriptive as you can in your notes and drawings.

 

Drawing Guide

We recommend that you submit a couple simple drawings:

• Doesn’t need to be computer generated

• Pencil or pen on paper is just fine

• Just make sure it shows:

  • A top-down view with fitting size, locations and orientation. Please indicate bow, stern, port, starboard on your drawing so we are all on the same page on how we are reading the drawing.

  • An end view with overall tank shape, including dimensions

  • Any special notes, clearances, or tab placement

  • We also encourage you to send clear pictures of the old tank as well (if possible). These really help clear up any potential questions we may have regarding your drawings.

Most people just scan or snap a phone pic of their sketch and upload it with the order — that works fine. Just make sure it's legible.

If you're unsure whether your drawing is acceptable, we've created a Drawing Examples page that shows exactly what we're looking for — from ideal to borderline. It's worth checking before you upload something that may get rejected.

 

Final Reminder

We are not responsible for tanks that do not fit due to incorrect or incomplete measurements or lack of details in your notes.

By checking the box at checkout, you confirm:

• You have measured your space accurately

• You left at least 1/4" clearance around the tank

• You accounted for tabs, hoses, and install space

• You have reviewed this page fully

• You understand that we build to your provided specs exactly