Ferrocement Fittings and Waterproofing

[PoolParty]

Dear Cruisers,
This is my first post so please be gentle.
Yes I realise this is a nautical forum but those who have experience with ferrocement boats may be able to help.
I am building a ferrocement swimming pool which will have the water on the inside as opposed to the outside as you no doubt hope to find with a boat.
Also my pool wont actually be going anywhere (hopefully) but apart from that, they have much in common, hence my interloping amongst you - hope that's ok.

Anyway, I wanted to know what the modern ferrocement owner uses to waterproof and paint the outside of his or her boat with.
I presume some some sort of epoxy paint, but I wanted to know if you use some sort of flexible coating before applying the epoxy as expoxy paint isnt know for being particularly flexible and whilst a pool wont flex as much as a boat, if there are movement related cracks, I dont suppose epoxy paint would accommodate them that well.
There is a school of thought which says that a low water content mortar made with superplasticiser is sufficiently dense not to have to worry about waterproofing. This is to my mind risky especially in a salt chlorinated pool or marine environment with such thin mortar cover and a heap of thin metal meshes just waiting to rust away, only millimeters below the surface.
Thoughts on that welcome.

The other issue which I am sure ferro boat owners will have had to deal with many times, is fixtures. Whilst I wont need to hang portraits of my Great Aunt Agatha or put up shelves for homely knick knacks, I will need to fix a skimmer box and lights by using screws. This I find worrying because even if I can drill
decent holes into the walls, the screws will be right into the mesh meaning a nice hole for water to get straight into the metal. I suppose I could cover the screws with sealant, but this seems less than satisfactory.

many thanks,
PoolParty