Association Forum - What Causes These Black Spots?

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

General Sailing Forum

What Causes These Black Spots?

New Topic

Topic Locked

Printer Friendly

Author

Topic

Kper
Captain

Member Avatar

USA
417 Posts

Initially Posted - 09/19/2014 : 04:43:31

And how do I get rid of them for good?
They were there when we purchased the boat this past spring although not as bad. We pressure washed them away and they seemed to have gone from almost non-existant to this bad in the past 2 or 3 weeks. I just discovered a fuel leak in the fuel line, could this have anything to do with it?

Edited by - on

Akenumber
Navigator

Members Avatar

USA
247 Posts

Response Posted - 09/19/2014 : 05:15:54

Looks like mold to me. Another user recommended soft scrub with bleach. I tried it and it worked great.

Edited by - on

islander
Master Marine Consultant

Members Avatar

USA
3992 Posts

Response Posted - 09/19/2014 : 05:23:20

Kyle we all get those mold/mildew spots. You can use a bathroom mold/mildew cleaner or what I do is simply spray the surfaces with a bleach mixture, let it sit then wash it away. For some reason the mold loves the area around the gas locker the most. Zep makes a concentrated house wash that is made for pressure washers but I put it in a spray bottle undiluted and wash the boat with it. Works very well on the mold,bird poop etc and leaves the boat white again without costing much. A gal will last a long time for under $10.http://www.homedepot.com/p/ZEP-128-oz-House-and-Siding-Pressure-Wash-Concentrate-ZUVWS128/202056507?MERCH=RV-_-RV_gm_pip_rr-2-_-NA-_-202056507-_-N

Edited by - on

Kper
Captain

Members Avatar

USA
417 Posts

Response Posted - 09/19/2014 : 05:53:11

I should have just listened to the Mrs. Mold, she said, but would I listen? I'm always worse-case scenario thinking it was something far sinister! lol

Thanks everyone.

Edited by - on

Ben
Master Marine Consultant

Members Avatar

USA
1234 Posts

Response Posted - 09/19/2014 : 06:35:10

Kper, that's exactly what my 1987 C25 would look like towards the end of the season. I think I read somewhere that it's because the gelcoat of boats of that age have worn away some and become pitted, so they're more prone to having moisture held in those tiny gelcoat pits. this gives the mold a chance to take hold. For years I would do the softscrub thing, and it truly did work very well. However it IS an abrasive, so would take away a little gelcoat with it as I softly scrubbed the mold. I ended up switching to Tilex Mold and Mildew, which also works very well and is not as abrasive.

Edited by - on

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 09/19/2014 : 07:16:58

Before launching in the spring, I wax the cockpit, and the rest of the boat (1980), to keep dirt and grime at bay. I'm not a fan of abrasive cleaners on gelcoat.

Edited by - dlucier on 09/19/2014 07:29:29

islander
Master Marine Consultant

Members Avatar

USA
3992 Posts

Response Posted - 09/19/2014 : 08:49:14

quote:
I'm always worse-case scenario thinking it was something far sinister!

Alright, We lied to you. The truth is that your boat has the dreaded BLACK SPOT DISEASE! There is NO CURE! Don a Haz-Mat suit and burn the boat IMMEDIATELY and anything that has had contact with it. See your doctor for ANYTHING lasting more than 4 hours. Contact the center for disease control.

Edited by - on

Kper
Captain

Members Avatar

USA
417 Posts

Response Posted - 09/19/2014 : 09:27:40

quote:
Originally posted by islander

See your doctor for ANYTHING lasting more than 4 hours.

Wait a minute, isn't that for something else?

Edited by - on

Frank Law
Navigator

Members Avatar

USA
159 Posts

Response Posted - 09/19/2014 : 10:03:30

I believe the spots / mold or whatever it is comes from the ethanol gas fumes ... I get the same stuff inside our gas tank cap on our cars ..This has been happening for a number of years now ..

FRank Law
"ABOUT TIME" --FOR SALE IN SWAP MEET
# 3519
SR , SWK

Edited by - on

shnool
Former Capri-25 Tech Editor

Members Avatar

USA
1032 Posts

Response Posted - 09/19/2014 : 10:20:02

the ethanol fumes is an interesting thought... I attributed it to enclosed hot/humid area, but you are right it was worse in the fuel locker for me in my Capri 22.

Yep, wash, bleach (softscrub is a good choice with bleach)... but then a wax and it'll hold off for quite a bit... a dark shady spot in the marina will make it worse (ask me how I know).

Edited by - on

GaryB
Master Marine Consultant

Members Avatar

USA
4275 Posts

Response Posted - 09/19/2014 : 16:15:32

I work near the oil and chemical plants along the Houston Ship Channel. There are large steel storage tanks in some of the tank farms that have the same looking stuff around the vents at the top of the tank.

BTW... my boat gets the same stuff. Zep makes a mold and mildew cleaner you can get at Lowes or HD. Works better than anything else I've used. As soon as it hit this stuff it starts killing it. No scrubbing. Let it sit for a couple of minutes and hit it with a garden hose and your done. Makes the gel-coat look bright white.

Edited by - on

pastmember
Master Marine Consultant

Members Avatar

2402 Posts

Response Posted - 09/19/2014 : 19:59:40

It does not happen in Kansas. I think most boats are in very humid climes.

Edited by - on

OJ
Master Marine Consultant

Members Avatar

USA
4382 Posts

Response Posted - 09/19/2014 : 20:07:30

Tilex works well for us.

Edited by - on

sfsmith
Navigator

Members Avatar

USA
120 Posts

Response Posted - 09/20/2014 : 06:05:16

The gas locker attracts black mold, and it seems to spread from there. Clorox Cleanup works pretty well. I installed a small louvered vent in the vertical face of the locker lid, and the problem has almost disappeared. I just did the end-of-season cleaning, and there was very little mold.

Edited by - on

Voyager
Master Marine Consultant

Members Avatar

USA
5231 Posts

Response Posted - 09/20/2014 : 12:10:51

Yep - the gasoline fumes have an oily component that sticks to the gelcoat, so between regular mold and the sticky oil precipitate attracting dirt, it seems that the fuel locker is the place that the black dots start from first. I notice that the dots get worse during periods of higher humidity (right after a rain) and fade a bit in dryer weather.
I mentioned the dots to a friend with a gasoline-powered powerboat (Fortier 26), and he recommended purchasing "Simple Green" cleaner. Very similar to "Islander"'s first comment about Zep, you'd mix the cleaner with water in your own spray bottle. My buddy said that chlorine bleach is too abrasive and prone to eating the gelcoat, so he avoids using it unless he's tried everything else first.
He also recommends, clean it up with Simple Green then hit the spot with a quick dash of wax or polish. Cleans, then restores the shine.

Edited by - on

OJ
Master Marine Consultant

Members Avatar

USA
4382 Posts

Response Posted - 09/20/2014 : 12:43:16

quote:
Originally posted by Akenumber

Looks like mold to me. Another user recommended soft scrub with bleach. I tried it and it worked great.

FWIW, we used to use Soft Scrub on our previous 1981 C25. Later sold the boat to someone in the marina. The following season he asked if I had used Comet on the deck and cockpit. He went on to explain that the gel coat was looking thin in spots - and was wondering if an abrasive cleaner was responsible. Again, FWIW.

Edited by - OJ on 09/20/2014 18:27:02

Dave5041
Former Mainsheet Editor

Members Avatar

USA
3754 Posts

Response Posted - 09/20/2014 : 17:38:42

Whether it's mold or a byproduct of hydrocarbon vaor oxidation, it predates E-10, it scrubs of easily enough. I just use a soft scrub brush with Starbrite deck cleaner.

Edited by - on

Kper
Captain

Members Avatar

USA
417 Posts

Response Posted - 09/20/2014 : 17:40:18

Thanks, again, everyone.

Edited by - on

TakeFive
Master Marine Consultant

Members Avatar

2269 Posts

Response Posted - 09/20/2014 : 19:24:05

I'd love to see some real science on this subject, particularly to determine whether the black is mold or just dirty sludge.

I've seen the black spots on my C250 gas tank and inside the locker. But I've never seen it on any of my other boats' gas tanks. They are not stored in a confined space like the C250 tank is.

I have also seen black gunk inside the gas door of my son's Honda Accord. When it was the family car and kept in a garage, we never saw it. But after he took it to college, the black sludge appeared inside the door. (There are also numerous references to this phenomenon on the web.)

Based on all this, I always assumed that it was nothing more than gas fumes that mostly evaporated, but the higher distillates stuck to nearby surfaces and allowed pollen, dirt, and other stuff to stick onto it.

In my experience, a little gasoline on a rag is effective at taking this stuff off, as you might expect.

I've never seen a shred of evidence that it is mold. I would think anyone with a microscope could look at the stuff and determine if it is mold or mildew. But after searching Google, I see nothing but idle speculation that it might be mold. No hard evidence.

Edited by - TakeFive on 09/21/2014 07:46:37

pastmember
Master Marine Consultant

Members Avatar

2402 Posts

Response Posted - 09/21/2014 : 07:01:25

RE SoftScrub:

SoftScrub is for people who wash their boat decks every couple of years like me. It was developed for fiberglass bathtubs and showers. It is particularly useful as a first time hull prep for PolyGlow because it will remove oxidation. I would nor recommend it for regular use, as in those people who wash their boat every time they sail. It does leave a flat finish which is best for decks. I scrubbed my deck and cockpit with it yesterday because this year's plague is spider poop; more than anyone can remember. I never thought I would miss May Flies.

I admire those for whom a clean and shiny boat floats their's... but it has never been important to me. I do things as maintenance and modifications and do not worry about the outside of my boat for looks. We all admire a pretty girl but my boats are more the good personality type.

Edited by - on

redeye
Master Marine Consultant

Members Avatar

3474 Posts

Response Posted - 09/22/2014 : 04:10:41

< some real science on this subject >>

So anyhoo.... sometime back I went to the George Dickel still in east Tenn.. I'm a photographer and I couldn't help noticing the whole place had a kindaofa "Hard Black" or what I'd call a distinct D Max. The wood on the buildings and everything had an interesting contrast, all the gray areas went to black. Looked like the ads and their bottle label. Late in the tour the guide told us that if you noticed there was a black... I think he said yeast, or from the yeast, I don't remember him saying mold but rather fungus, on the trees and buildings around the main building.

OK that didn't take long ..googled and

"humidity, promotes the growth of a fungus called Baudoinia compniacensis on all the trees ... Black Trees All the trees around the distillery have black bark."

And Wiki...

"Baudoinia compniacensis is a cosmopolitan colonist of outdoor surfaces subjected to extreme daily temperature shifts, elevated high relative humidity, periodic wetting, and ambient airborne ethanol."

[url="http://www.nytimes.com/2012/08/30/us/kentuckians-fed-up-with-a-fungus-sue-whiskey-makers.html?_r=0"]And this...[/url]

"It is during the maturation process, not during fermentation."

SO... while we are ageing our ethanol it gasses off something that a black fungus ( or mold ) likes...

Edited by - redeye on 09/22/2014 05:30:04

dmpilc
Master Marine Consultant

Members Avatar

USA
4593 Posts

Response Posted - 09/22/2014 : 12:45:01

Great info, Ray.
BTW, were you out sailing this past weekend? I was down there at LLSC for the Catalina 22 Gone With The Wind regatta; thought I might have seen your boat.

Edited by - on

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 09/22/2014 : 14:32:53

quote:
Originally posted by pastmember

SoftScrub is for people who wash their boat decks every couple of years like me. It was developed for fiberglass bathtubs and showers.

Are you sure? Looking at the Soft Scrub web site, they only mention using the Soft Scrub spray cleaner (non-abrasive) for fiberglass. Most tub/shower manufacturers recommend non-abrasive cleaners.

[url="http://www.hamiltonbathware.com/care.cfm"]Hamilton Bathware - Care and Cleaning[/url]

Edited by - on

Voyager
Master Marine Consultant

Members Avatar

USA
5231 Posts

Response Posted - 09/22/2014 : 17:30:45

My wife told me about Weinmann's fiberglass and acrylic cleaner for jacuzzis, bathtubs and shower stalls. It works well on the plumbing fixtures but never tried it on the boat. Doesn't scratch or leave a residue and it gets the grime, and the shower shines up pretty nice. Might be worth a try.
Ray - thanks for the research on the spots. Makes sense to me: the black spots come off with bleach, detergent or solvent.

Edited by - on

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.