Help! No hot water!

I have a torrid 120v tank water heater, I have replace the element and the thermostat and power to it but it wont heat up!
I was told that the compartment flooded and submerged half of the tank (multiple times) there is plenty of rust for evidence. But it was supposedly working recently.
Using my multimeter I have 120 from black to ground but i also have 120 from white to ground. Black to white reads 0 volts. I residential, this would tell me that i have two possative wires that are the same phase (not a 240v config) and no negative. I am not sure if it would be the same on a boat. How could I have two hot wires and no neg if the water heater was working before? Am i missing something? Will a boat neg read 120v instead of 0v?
Thanks for any help
Jp

You have an open neutral (white lead). Track it down and find where volts are and where volts are not. Between those two is a fault.

It sounds to me like the hot (black) and neutral (white) are shorted together. It there is zero volts between them and 120 to ground from both of them I suspect that they are shorted. Boat electrical and home electrical are different enough that you can create a dangerous situation if you are not sure what you are doing. Sounds like you may have a lot of electrical problems lurking around if the boat was partially submerged several times. I would power everything down and ohm between the hot and neutral and see if they are shorted. I would recommend getting a certified marine electrician to look at it and make some recommendations. Oh BTW, welcome aboard.

Comodave said:

Sounds like you may have a lot of electrical problems lurking around if the boat was partially submerged several times. ....................... I would recommend getting a certified marine electrician to look at it and make some recommendations.

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+1

Good idea! I didnt think about testing continuity between them. I'll give that a look.

Just the water heater was submerged not the whole electrical. Bad bilge pump has since been fixed

Disconnect the white and black from the tank. With power on test your voltage. If you are still at zero whit to black and 120v white to green then you have a problem with your wiring. If you are at 120v white to black and 0 white to green your problem is with the hot water heater. Based on your description either is highly suspect.

If in the wiring, trace it back to the bus, wouldn’t be surprised if you find a flooded junction box.

Ski in NC said:

You have an open neutral (white lead). Track it down and find where volts are and where volts are not. Between those two is a fault.

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Like Ski said. You have a broken neutral somewhere. You are reading the 120 volts on the white because it is connected to the hot through the heating element.

Ski in NC said:

You have an open neutral (white lead). Track it down and find where volts are and where volts are not. Between those two is a fault.

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Duvie said:

Like Ski said. You have a broken neutral somewhere. You are reading the 120 volts on the white because it is connected to the hot through the heating element.

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+1
You have voltage but likely no amps therefore no heat
Disconnect wires from heater and retest - if 0V on white then start continuity testing and find the open.

Duvie said:

Like Ski said. You have a broken neutral somewhere. You are reading the 120 volts on the white because it is connected to the hot through the heating element.

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This.

Personally, I would just replace the tank. I presume it is a 5 gallon tank. If it has sat in water the insulation and tank are probably ready to fail anyway.

If the water you run through it smells like sulfer it is probably loaded up with sludge anyway. The tanks are cheap and generally easy to replace.

BTW, you will still have to track down the bad wire but that should be easy.

pete

The bad wire could be internal to the water tank. A friend had a short between neutral and ground that was internal to his water heater.

A correction, Torrids are not cheap but they are overkill for most of us because they will go 20 years and most of us sell way before that...