Prolong engine/trans treatment?

[Fman]

Is anyone using this in there boat? I know its been around for a long time, wanted to find out if anyone on this site has used it. Good or bad results?

Heres the link: http://www.prolong.com/index.html

[michael hunter]

I never use additives but I do use synthetic oil Mobil 1 or Castrol syntec 20w50.
I have using them for 20 plus years and never had any engine problems.
I change every 50 hours with a good filter . I dont think Prolong will hurt anything as
long as you change the oil as recommended by Indmar.