If we had the model number, we can be more accurate, but this I can tell from the 1986 sales brochure.
Not sure on the 16 ft length where you are measuring that from. Rear of the bumper to tow ball or the box length of the camper without the tongue on the front? Sunline used rear of bumper to tow ball.
This may help for what your needs are.
In 1986, Sunline made a Saturn Model T1550 that is 15' 11" bumper to tow ball with a 21 gallon grey water tank and a black tank that is 10 gallons.
They also made a Saturn T1650, T1651 and a T1670 all which were 16' 10" long bumper to tow ball. All this these models had a 25 gallon grey and 25 gallon black tank.
If you are looking to just dump the black tank, you would need at least a 25 gallon or larger to cover all those models if you want to dump the tank all at once. As you can see, just knowing 16 ft and not where is was measured from, or a model number, makes it harder to narrow this down any closer.
I found this info from the 1986 Saturn sales brochure in our files section.
To get to the files section, you need to be logged into the forum.
At the top of the forum are tabs, look for the word "FILES" click it.
Once into the files section, scroll down to the "Sunline Brochures" section. Go in there and find a sale brochure for the camper you are looking at and down load a copy. There is a lot of good info about your camper in there. have a look.
Hope this helps
Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
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