C-Dory 22 Cruiser water Tank Capacity - Not 20 gallons

drbridge

A few years ago I completely drained our water Tank on our 2004 C-Dory 22 cruiser. I then filled it one gallon at a time using one gallon jugs for the purpose of marking graduation lines on the clear vent tube so that we would be able to have an idea of the water tank level while on longer trips. There was no water line visible on the vent tube until there was about 4 gallons in the tank. I then used a marker pen to draw a line every time I put in a gallon. This worked very well and also revealed to me that our tank does not hold 20 gallons as advertised, but only 16 gallons. This was all done with the the boat sitting level on the trailer. I have also removed the wood cover/shelf that was originally mounted above the tank. This allows for more storage and also visibility of the tank, so I can confirm that the tank was full at 16 gallons. I don't know why ours would be any different than anyone else's, so for planing trips you might want to note the true capacity of your tank. We also carry about a half dozen one gallon containers with us that we use for drinking and the tank water mostly for other uses. We also use the jugs to refill the tank when we are at a Marina while cruising, as it is about as fast and less hassle than dragging out a hose to fill it and we don't have to take up space packing a hose. Most of the marinas where we boat don't allow boat washing, so we can't use the hose for that either. water also tastes better not running it through a hose. Just wondering if others have measured the capacity of their water tank.

bridma · Posted: Fri Apr 07, 2023 5:44 pm Post subject: water tank capacity

I believed my water tank capacity on my 2009 boat was 18 gallons. So there's another number to throw into the mix! I will fess up, I never actually tested the capacity.
Martin.

jkidd · Posted: Fri Apr 07, 2023 6:19 pm Post subject:

What was the temperature of the water when you did that. Changing the temperature of the water will cause that. 50 degree water will be more dense than 100 degree water.

Robert H. Wilkinson · Posted: Fri Apr 07, 2023 7:33 pm Post subject:

Was your Gal. jug US or Imperial? A US gal. measures 3.78 liters and an Imperial gal. measures 4.54 liters.

I find that fuel tanks are usually rated in US gal. but not sure about water tanks.

Rob

drbridge · Posted: Fri Apr 07, 2023 8:07 pm Post subject:

Was your Gal. jug US or Imperial? A US gal. measures 3.78 liters and an Imperial gal. measures 4.54 liters.

I was using gallon milk jugs filled to the top, and that would be US Gallons. I would think any vehicle/vessel that was made / sold in US would have all liquid capacities measured in US gallons, quarts etc. etc. I know that my fuel tanks hold exactly the 24 gallons that they advertised.

What was the temperature of the water when you did that.

Water Temp was about 50. Since water expands about 4% from room temperature to boiling I do not think that temperature can be an important factor in this equation. The difference I measured between advertised capacity and actual capacity was 20%.

jkidd · Posted: Fri Apr 07, 2023 8:28 pm Post subject:

What you tank dimensions? 1 gallon being 231 Cubic inches.