Hi Bernd,

     When I purchased SM37 in 2016 the previous owner stressed to me to always keep the tank full and to always use the Baja filter.  He said in the 16 years he had her no one drop of fuel went into the tank other than through the Baja.  He did two circumnavigations and claims to never have had an issue.  I followed his advice.

A year into my ownership, I performed maintenance changing out the Racor filter and the Volvo engine filter.  Both were clean.  I intentionally ran the diesel tank dry and used a boroscope to inspect the tank and found it also spotless.    I continued to use the Baja filter and also add a Biocide each time I fill up.  

 

 There are two reasons to keep the tank full, one is it prevents condensation from forming in the tank as temperature changes.  Gas expands and contracts with temperature and draws in moisture.  In a climate with daily temperature changes the cycle can pull in a notable amount of moisture after a period.  The moisture aids in the growth of bio-organisms that feed on diesel.   Second reason at least  for me in the Atlantic and Caribbean, is to have the ability to run from a hurricane at a moments notice.  Amels have large tanks which give them excellent range in a pinch I like to have that capability.

   Regards,  John

John Clark

SV Annie SM 37

Brunswick GA   

On Mon, Feb 10, 2020 at 10:13 AM Bernd Spanner <bernd.spanner@...> wrote:

Why fill up your tank to the max when you know where you want to go?

I think filling it up to the max only makes sense when you go for a really long passage and then you add some anti diesel bug adds.
When you fly on an airliner to your boat they only take as much fuel as they need plus alternate, contingency and a bit more for unforeseens.

--
Bernd
SN 119 / Cascais, Portugal