First, let me congratulate you on your choice of boat. The SouthCoast 36 was very high on our list of choices when we were looking for a good comfortable cruiser a few years ago, and I have many photos of Southcoast 36 interiors as a source of motivation for our own interior
rejuvenation whenever that happens.
I am posting
here because I just went through a process that I suspect is very similar to what you face. Our Swanson 42 had a failed keel
tank (freshwater) which was located under the engine
. In December I finally got around to dealing with the tank, and I learned a bit in the process, which may apply to your situation.
First, I am going to assume that given the very similar pedigree of our boats that the construction methods will have been the same, and certainly my very careful analysis of the SC36 years ago suggests they have a lot in common with our Swanson 42.
Second, I am going to assume that the previous owner did not decommission the tank just for the heck of it, in the case of our boat they most certainly did not give up on 420 litres of fresh water storage
just for a simple problem.
So, I won't bore you with the details, but I pulled out our engine
(all 450kg) in December and opened up the failed keel
tank from the top, using an electric
jigsaw. Then I extracted the utter evil gunk, removed the hideous failed bladder tanks
that had been inserted to get around the original problem, washed it all out, sat back and worked out what had gone wrong.
Well, it appears that the keel tanks
were lined with some kind of epoxy
or hard setting liner which had cracked and failed, exposing the inside of the keel to the tank and thus probably causing foul "osmosis" tasting water
(Acetic acid?) When this happened (around 15 years ago) the owner at the time just pushed in some flexible bladder tanks and used these. But of course they failed (they did not fit properly, they never could have, so they chaffed to bits in under five years) and the result was two big black pvc bags floating in scummy solution of water and diesel
and goodness knows what.
So, my point is, the pressure test is a great idea, and if it fails I would seriously recommend you do NOT put any diesel
, or ANY liquid in those tanks as cleaning
them out will become a nightmare, particularly if they are full of now-contaminated diesel. I suspect you will find they too have a failed liner coat (maybe someone here can tell us what the layer of brittle, semi transparent lining material is likely to have been) and that they need some kind of sensible insert to be used again.
Next, I know you don't like the idea, but I would suggest that pulling the engine is worth the hassle. The SC36 came with around 50+ HP from memory, so the weight should not be a major concern, and you'll have a chance to clean up the engine if it needs it, clean all those fiddly bits of the bilge
, get to know a really critical and time consuming part of your boat (the engine) but most importantly, you'll be able to open up the tanks properly and make a smart decision on the best way forward.
I don't know what the best way forward will be. I don't even know what I will do with ours right now. We are ok for diesel and water storage
, at least for coastal cruising, so there's no great pressure to do anything, but if I had to I would seriously consider custom made poly tanks based on the suggestions of a few CF regulars who's opinions I highly respect.
Certainly, after my experience, I will never fit a bladder tank, but I admit to a bias that may be blinding me to their virtues. So be it.
Happy sailing, very envious of your lovely boat...