Boat Cover Cleaning

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
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Boat Cover Cleaning

Postby Jefecinco » Wed Jun 15, 2016 7:22 pm

A couple of days ago I removed the cover from our 190 Montauk to get ready for a fishing outing. I found the underside (inside) of the cover had a fair bit of mildew present. I removed the cover, cleaned up the boat, charged the batteries and finished preparing for fishing.

The following day I unrolled the cover and turned it over with the underside now up. I spread the cover out on the driveway and weighed down the bow and corner areas with a few gallon bottles. I rinsed the cover then using a soft bristled deck brush. I washed the cover with a mild car wash mixture. After rinsing I found that the washing had not been very effective. The next day when the cover had dried I reinstalled it on the boat in an upside down position. This morning I mixed a couple of gallons of water in a bucket with some Tide He and some household bleach. I then washed down the cover with the same brush and rinsed it very carefully. As luck would have it it began to rain just as I was finished rinsing the cover. It rained lightly for about two hours.

After a couple of hours of sunshine I checked the cover and found that although the mold appeared to be gone somesome light brown spots remained. I plan to leave the cover installed upside down over the weekend to allow the sun to do it's best to kill any remaining mold spores and hopefully bleach out the remaining stains.

The fabric used for the cover is Raven Mills Sundura, a cover fabric recommended for damp climates with long hot summers. I'm considering adding a couple of vents to the cover to encourage natural ventilation to avoid a recurrence of the mold.

I welcome your thoughts on the approach used and the idea of adding vents.

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Re: Boat Cover Cleaning

Postby Beerspitnight » Wed Jun 15, 2016 8:38 pm

Hi Butch,

I wonder how the addition of the vents will affect the effectiveness of the cover. I had my boat covered with shrink wrap for two years and I was very surprised at the amount of dirt and grime that accumulated on the inside of the boat during that time. I had hoped that the wrap would have prevented the intrusion of dirt, but that was not the case.

I'll assume that your boat cover is not used for long-term/year-long coverage, so perhaps the intrusion of dirt will not matter in this case.

I also wonder if there is a product that you can apply to the underside of the cover to prevent the mold from reappearing in the future.

1989 MONTAUK 17

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Re: Boat Cover Cleaning

Postby Jefecinco » Thu Jun 16, 2016 9:37 am

The cover is on the boat when it's not in the water or being maintained in some way. You could say it's a full time, year round cover. To complicate matters the Montauk is getting little use in the past couple of years because we find ourselves using the Sport 13 much more.

The Sport 13 is a very easy and convenient boat to use for only two people when the weather is friendly. It launches and recovers easily and the cover is a snap to remove and reinstall. Washing takes perhaps 45 minutes including the engine flush. My Admiral is disinclined to use it in our Mobile Bay Delta due to the low freeboard and the abundance of alligators, but we use it a lot in the Bay and in the beach area. Recent events in Orlando have done little to encourage her to change her position.

I should sell the 190 Montauk and simply charter a guide boat when I want. Overall, that's the smart move but I'm emotionally invested in our Whalers.

Your suggestion to use a mold preventer is a good one. I'm looking into that and if I can find one that will neither damage the cover nor the boat I'll try it. I'll post here if I get lucky.

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Re: Boat Cover Cleaning

Postby Masbama » Thu Jun 16, 2016 10:09 pm

Being in Mobile I know what you are going through. My polyester cover has some gaps that allow air to get through. Still some mildew after a long period of non use but I find using Clorox bathroom cleaner that has some bleach in it and letting the the boat and cover sit in the sun does wonders for cleaning both. Rinse with water after sun time though.

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Re: Boat Cover Cleaning

Postby Jefecinco » Fri Jun 17, 2016 8:55 am

Thanks for the tip. I'll look into the Clorox Bathroom Cleaner. I found an article in "Practical Sailor" recommending Concrobium as a result of tests they conducted. Carrie, at Carver Covers recommends 303 Fabric Protector treatment to minimize water intrusion.

I will reapply the 303 to the cover but I'm fairly certain the moisture on the inside is condensate. During the heat of the day hot highly humid ambient air enters under the cover. In the evening and overnight the temperature of the cover drops near or below the dew point and the water in the atmosphere condenses on the inside of the cooler cover. Carrie also recommended a couple of products designed to remove moisture from the air but I don't believe they are very practical in this application.

I'm tempted to try the Concrobium as a preventive measure and the bathroom cleaner the next time I wash to cover.

I think the measures mentioned are useful but have a feeling that better ventilation under the cover is the best move. I'm not overly impressed with the vents Carver offers for sale so more research is called for.

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Re: Boat Cover Cleaning

Postby ratherwhalering » Fri Jun 17, 2016 1:13 pm

I have found WET AND FORGET mixed 5:1 with water removes all mold and mildew over the period of about 3 weeks. I have a friend who is a professional boat maintenance worker and he has used this product for years without and noticeable detriment to Sunbrella fabric or stitching. I used a garden sprayer for one application and ended up wetting the cover every few days with water (not much rain her in California this spring). Results take a while but the process was very, very effective. I had quite a bit of mildew/mold on the inside of my newer Mills cover, which ended up on the interior of the hull. I think I should have turned the cover inside out, done the application, and probably would have had less clean up.

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Re: Boat Cover Cleaning

Postby CarverCovers » Tue Jun 28, 2016 6:31 pm

We would always recommend checking with the cover manufacturer for the proper care instructions. There may be different care instructions for different types of fabrics etc. There are several options available to keep your cover clean. Make sure your cover is properly supported, vented support poles are an excellent option because they both support the cover and also allow for additional breathability on a cover. Avoid letting water, snow or other materials like leaves and sticks stand on the boat cover. Also, always make sure the the cover is secured - by means of tie-down straps, suction cup tie-downs or mooring bags.

Regularly brush off any loose dirt with a soft brush and rinse with lukewarm water. To clean, a solution of lukewarm water and mild natural soap such as Ivory™ may be used. Rinse thoroughly and allow to air dry. The use of detergent is not recommended as it may diminish the water repellent finish on certain fabrics and invite the growth of mildew. You can clean both the inside and outside of the cover this way. We also recommend the use of 303 Fabric & Vinyl Cleaner to safely remove dirt and difficult stains.

As a last resort, you can use a Borax solution - but extra care must be used if you use this method.

1 cup white vinegar
1 cup borax powder
2 cups warm water

Mix together in bucket / spray bottle etc. Apply to cover – leave on for up to 10 minutes MAXIMUM (this is extremely important).

Rinse – make sure it is rinsed VERY well.

Re-apply 303 Fabric Guard.

Regular exposure and cleaning can diminish the water repellency of certain boat cover fabrics over time. The water repellent finish used on most boat cover fabrics allows water to bead and run off similar to that of a waxed car. When water beading diminishes, we recommend the use of 303 High Tech Fabric Guard after a thorough cleaning to restore the water repellency of your cover.

Allow boat cover to dry thoroughly before folding for storage.

There are supplemental care instructions for the Sunbrella fabric, please feel free to contact me if you need additional information.