IP40 water heater replacement questions

I need to remove the 11 gallon Atwood water heater, model EHM11-SM-FHX, in my IP40 so that I can replace my davit base on the port side.  I might just replace it while I have it out.  I have a few questions that you all might be able to help with.

1.  How is the water heater attached to the shelf it is installed in?  Where are the screws that I need to get to to de-install?  I see a tab on the back of the unit that is screwed to the shelf but I am sure there are more than that.  
2.  What is the de-install process?  Any tips?
3.  What have people used to replace their original units?
4.  Does anyone have a manual or a link for a manual for the original or replacement?

Thanks!!!

Bill,

I replaced the OEM many years ago. Memory is fading, but I believe I took the original apart piece by piece to extract it. Did not have to enlarge access port. I replaced with a 6 gal Isotherm (Isotemp). Very happy with the results. Insulation keeps water warmer far longer than Attwood.

Hi Bill, In 2019, we replaced the hot water heater on our IP380 with the same as original, except in White Aluminum instead of gal steel. - Seaward Marine Water Heater - 11 Gal- Rear Heat Exch 120V - White Epoxy, model S1100W. I ran out of time, so had the yard do the install. I think there were only 2 tabs, one in front, other in rear. It came out through the access in aft cabin. The yard also replaced the engine hot water hoses (20 yrs old) and added shut off valves near the engine, so easier to service later (if needed). I think the harder part may be replacing the hoses at the back of the hot water tank. We got our tank at Defender - but currently back ordered.

Looking for your tank, I found pix and specs here, but not sure if this is exactly yours, www.boatandrvaccessories.com/products/at..._sid=22740f3fc&_ss=r. "This product has been discontinued by the Manufacturer and replaced by Attwood Seaward F1100" . You may just have to do web research and find a good replacement.

Hi

I have recently replaced the hot water tank on my 350. I fitted a johnson aquaH 22 litre.

I found that the insulation on the original whale type was almost non existent & now the water stays hotter a lot longer. 
with the addition of a mixing valve at the tank you waste less hot water too.
Its worth fitting a small expansion vessel onto the cold inlet side of the tank.

regards

john