Brown spots on tne vinyl of boat

[evil 13]

I have a 07 malibu wakesetter lsv i just bought it new last year in june.I have 43 hours on it preatty much use it every weekend.The problem i have is that after not using my boat for i month i take off the cover and the first thing i see are some brown spots they look like rust stains.I know there not rust stains because there is no metal next or near the stains.The stains are in the back on either corner of the boat.They are located in the back compartment doors that raice up.Like i said the stains are in the same area just different door.I dont know how 2 post pictures but ill try.Has anybody had this problem/ i think i had seen a topic about but not sure.The other thing is that with the sum the stains kind of fade away but u can still see it

[radioman]

the brown or black or yellow spots are mildew. I have to flip up all our seat at the end of the day to dry , before boat is put in the shed. the sun lightens the spots, because uv rays in the sun kills mildew. use a cleaner with an algecide and a soft brush to remove most of it.

[eyepeeler]

the brown or black or yellow spots are mildew. I have to flip up all our seat at the end of the day to dry , before boat is put in the shed. the sun lightens the spots, because uv rays in the sun kills mildew. use a cleaner with an algecide and a soft brush to remove most of it.

Sounds like spider excrement.

[WakingMeHappy]

I just started having the same problem on my 99 Sunsetter but thought is was old-age wear. I hadn't thought about mildew. It's only on the boot (storage) cover. I always remove the seats and store them in the garrage after they dry.