Pink Spots on Upholstery in Bowriders and Pontoon Boats…Why?

Are you seeing pink blotchy or round pink colour discolouration on your expensive particularly white or off white vinyl upholstery?  The pink blotches  may also be found radiating near seams and stitching.  My name is Tom Welsh and I am the general manager/owner of Huntsville Marine since 1986.  I remember well in the late 80’s pink mold on particularly the seam areas of white vinyl boat tops…..never could get it off either.  Recently I have seen and heard of numerous cases of the pink blotches being found again and on some fairly pricey boats as well.  One large marina in Muskoka ( not Huntsville Marine) seemed to be having numerous cases of it!

If you Google the topic you will find lots of information available including some causes.  For many years I though it was pink mold but apparently doing research it is actually caused by a bacteria called Serratia marcescens.  This is the same organism that sometimes is found in homes as a pink mold like smear in bathrooms and showers.  Regardless of that…the pink stuff makes a real unsightly mess on vinyl surfaces.  I continue to be of the opinion that moisture loading common with shrink-wrap is related to its appearance as well as the use of poorer quality vinyl’s where biological guard on the vinyl itself or the thread has not been applied…..the cost thing again!

To date I have been unable to find any cleaning agent that removes the pink stain left with the reaction to vinyl or where it is active.  In cold boat storage below 0 degrees C this organism cannot grow but in warm wet conditions it can prosper.  This is another reason why the proper application of biological control agents is recommended particularly in cases where shrink-wrap storage methods are chosen.  Add to this that boats should not when possible be shrink-wrapped when wet.

If you Google Pink Spots in boats, or Pink Mold in Boats you will find quite an extensive list of reading material.  Spray Nine will kill the organism and is safe when used as listed on boat upholstry but will not remove the stain.  I have read that Tilex when applied and left may remove part or all of the stain but highly chlorinated compounds are hard on upholstry.