Yes, You plumb the Raritan directly into the existing holding tank, remove all the Vac stuff.
Been using wema/,kus gauges on my Viking for years, absolutely nothing to worry about.
You can get Stainless units at McMaster Carr, they have a very didd range and excellent quality stuff.
I must admit that a fresh water boat has significantly less maintenance required. I'm still running original air units, none of the engine cooling...
Alot of us in the same situation. Mine's original from 1987, I changed the element in 2000 and that's it. But mine only runs 4-5 months a year.
Is the liner glass or some metallic product, a lot of heaters have glass liners, if it's glass then it may not be your source of problem.
Any particular reason your changing it? If it's not leaking most serviceable parts are available to purchase.
I ask because it's not like there's a line of offers to buy that boat.
The big question....did the OP of this thread really walk away...or did he just tell us that?