Waste holding tanks

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GBNI

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Oct 5, 2021
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Can anyone advise the size of the waste/holding tanks on a GB42MY?
Do they have both deck and sea discharge? THANKS
 
How old a boat?

To answer your question, you have to do your own examination of the vessel. You may find the original tank had a problem and was replaced or a previous owner decided they wanted more capacity. That's something that I would make the measurements on and calculate the capacity.

Regarding overboard discharge of the holding tank, it's generally pretty easy to follow the plumbing and know for sure. On my boat, I removed the overboard discharge as it was something I would never use and eliminated the failure points. If the next owner wants it, it's pretty simple to put back as the plugged seacock is still there.

Ted
 
As said by Ted if the boat is an older one it may have well had the tank replaced. I would just measure it and calculate the volume.
 
It's easy to calculate the size if the tank is rectangular: LxWxH in inches 231 (cu in/per gallon. You're measuring the outside dimensions, plus not every cu mil is useable space, so you'll want to reduce that number by 10-15% to a whole number to arrive at the approximate useable capacity.


Is the tank metal or plastic?


--Peggie
 
Can anyone advise the size of the waste/holding tanks on a GB42MY?
Do they have both deck and sea discharge? THANKS

Typically, GB-42s have a 45-48 gallon fiberglass holding tank unless, like Ted suggests, the original tank was replaced for some reason. A 48-gallon tank fits nicely between the center engine stringers and under the generator.

Only way to know for sure is to calculate its volume by measuring it.
 
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what year did holding tanks became mandatory? 1980's?
Before that boats did not have them so it was added.
 
Something else to be aware of is the pick-up pipe for the holding tank. GB used to make them of brass which would deteriorate in the sewage. I could only pump out about 25% of the tank and wondered why it would fill so quickly.
P.S. Boat is a 92.
 

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Looks familiar.
 

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