Fuel tank discrepancies: Did Albin misrepresent capacities?

[Mariner]

As part of a reworking of my 36 ET's fuel system (separate thread to come), I reached out to the metal fabricator that made the tanks in my boat (I won't name this Bristol, RI company) with some questions, and they sent me the original drawings, from Albin, that they used to make the tanks. The drawings from Albin indicate a capacity of 200 gallons each, but on the notes, added by the fabricator, it indicates a capacity of just 123 gallons each. The plates on top of the tanks also say 123 gallons. However, the exterior measurements of the tanks themselves, which match up with the drawings, seems to indicate a capacity of 200 gallons each. Albin originally marketed the boat as having 420 gallons of fuel capacity (200 gallons in each side tank, plus 20 in the belly tank). My gut, based on 20 years of running the boat says the 420 gallon capacity is probably more accurate, but I'll need to review the fuel logs to confirm.

However, when I asked the engineer at the fabricator about the sizable discrepancy, I was told that it was a repeated issue with Albin in that they would overstate their capacities, sending over drawings indicating a capacity higher than what the dimensions would actually provide, and then use that inflated number in their marketing.

So, what has your experience been? Does your Albin seem to have the advertised fuel capacity, or is it something less?

[Jkraft]

My 2006 31 is right on the money. I log my fuel usage down to the gallon. Mine is advertised as 300 gallons and really has 285 usable. Three tanks. Each stamped 100 gallons. Each actually holds 95

[Mariner]

I went down to the boat today and reviewed the fuel logs and can confirm that it is, indeed, 200 gallons per tank. So yes, I think the tank fabricator is wrong. It's odd that there's such a huge discrepancy, though.

[Norseman]

The single fuel tank on my 2001 -28TE had a placard from the tank manufacturer saying 136 gallons (or 132 can’t remember exactly)
Either way it was pretty darn close, I had a FloScan system measuring Fuel Used down to the 10th of a gallon and after some tweaking I got it down 3% accuracy: The most I filled was 120 gallons after burning 116 or so, close enough and still a few gallons reserve, but on longer trips I carried 5 gallon diesel cans.
On the other hand, the fresh water tank was all fake news: It was advertised as 36 gallons, but after emptying the tank, opening it up to make sure it was dry I used a hose flow-meter and got exactly 26 gallons, so we are 10 short.
Not so fast said some, the hot water tank held another 10 so that is 36 total…
Don’t think so, the hot water tank held 6 gallons and the 6 was not usable after the main water tank was empty,
(I considered plumbing in another pump so as to use all the un-usable water but ended up carrying blue water jugs instead.)
I am not sure, but thought I have seen the holding tank advertised as 20 gallons, but I know for sure it was only 10, ended up removing the small holding tank and installed a custom 18 gallon tank instead.

[Jastemwe]

I am wondering if anyone with an older 36’ trawler (1978-1982) knows what the diesel tank capacities per inch are. It is my understanding that my 1979 holds 175 gallons per tank —350 gallons total. My measurements/calculation of the tanks show that they hold at least 170 gallons each. Since we have no fuel gauge, only level-indicator tubes, I’m looking for a gallons/per inch from the top table. I could figure it out, but can’t see the width of the horizontal bottom of the tank to get an accurate cross-sectional shape.