greasy dirt inside Blue Hole canoe

I have a 1986 Bluehole Starburst royalex canoe. It has a greasy film inside the boat. I have a large yellow center airbag and it is covered in black stains. I had noticed but not paid attention to the problem until last night when I saw a friend with a similar vintage Starburst and it had exactly the same greasy dirty film inside. What it is? I store the boat in the same garage as my other 6 Royalex canoes and they are clean inside. It almost seems something is emanating from the inside vinyl layer of the boat and ending up on the surface. In some places it is just a thin layer of gray greasy film but in spots there are big black patches. Any insight out there? It does not clean off easily. It takes a strong cleaner and a lot of scrubbing. I have been unable to remove the stains that have transfered to the center air bag. The boat has wooden gunwales and thwarts and minicell pedestals.

If you are careful
you can get often get that stuff off the boat with acetone or methyl ethyl ketone. Don’t let this stuff pool in the boat as it is capable of eating into the hull. If you scrub too hard you can take the inner vinyl layer right off the Royalex.

You might be able to diminish the stains on the bags by scrubbing with a bristle brush using a solution of detergent soap and diluted bleach. Doubtful you will be able to get the stains out, however.

what is the greasy dirt
Do you know what the greasy dirt is? It seems to appear either on Bluehole royalex or perhaps royalex with a grey vinyl interior. My Old Town Tripper with a white/cream interior doesn’t have the issue.

If I push the film with my finger, I can get it to accumulate in a little pile, almost like a thin layer of almost dry contact cement.

mineral spirits dissolves it
Mineral spirits will cut the film. It’s worse (much blacker) on the part of the hull contacted by vinyl air bags.

I think some microorganism has learned
to live on dirty, intermittently wet, vinyl surfaces. I very much doubt that Blue Hole canoes are any different from other Royalex canoes with respect to what will grow on the surface. Differences in the pattern can be explained by the degree of sun exposure and how long a surface can remain wet.

Once a surface gets dirty, and gets some microorganisms that like the dirt, then the surface will attract more dirt, providing stuff for the organisms to eat.

I would recommend a strong vinyl cleaner. I suggest avoiding acetone, because if you make a handling mistake, it will perfuse through the vinyl and attack the ABS structural layer. A handling mistake can occur if you let a an acetone-soaked cloth sit on the vinyl while you go in to eat lunch. Happened to me.

I don’t think
that this phenomenon has anything to do with the maufacturer. I have a storage shed with whitewater Royalex canoes, 5 of which are made by the same manufacturer (Dagger). Some have been affected and others have not.

Out of curiosity, what’s the year of
manufacture of your other Royalex boats? What’s the oldest?

age of boats
My oldest Royalex boat is from the late 70’s. They range to late 90’s.

Tilex Mold and Mildew remover

– Last Updated: May-29-09 2:33 PM EST –

Spray it on, wait 5 minutes, hose it off....

Thanks. The Tiliex Modl and Mildew remover is working. I still have to scrub it but after a couple of applications the scum is coming off. Mold and mildew are pretty rare in Colorado since our climate is so dry but I bought the bought in Georgia. I’m guessing a colony of mold came home with me 15 years ago and has been multiplying ever since.

I would try bleach, I cleaned out a Discovery like that…the inside stunk from having like 100 too many fish laying in it. I filled it like a bathtub, dumped in some bleach, let it sit for a while and then flipped it over…then washed the inside with dawn and a sponge. It was LIKE NEW in there after that!

Krud Kutter
Removes the greasy dirt, but the stains remain. Works great.

Tilex is bleach
Looking at the label, it appears that Tilex Mold and Mildew remover is bleach at 10 times the cost.

Georgia apologizes for corrupting your
boat collection!


– Last Updated: May-29-09 10:54 PM EST –

Detergent Surfactants that cut the grease, and lift it away from the surface.....

I just know it works, and when in contact with organics, it breaks down into salt and water....

perhaps the same or similar …
… condition . Purchased a used (84) Royalex canoe last winter , very nice condition “except” for the oily stains that were hardened and dry .

I was thinking they would easily wash right out … man , was I incorrect about that , tried all sorts of milder things and rubbed and rubbed and rubbed w/o much reward , “until” , I posted about this situation and E.N. suggested carefully trying acetone .

The canoe cleaned up like new with each swipe of the cloth dampened with acetone … never did any damage to the vinal or abs (Royalex) , but made what seemed prior an immpossible task , a pleasure to do !!

I recomend trying it !!

I did some research on the net and discovered that there are/were special oils that were used in the Royalex manuf. to help maintain plyabilty (Royalex hardens with time) , and these oils “weeped” from the inside out … the canoe I purchased apparently had been weeping a long time and never cleaned/maintained , the dirty oil stains had basically become one giant connected stain that was determined to stay where it was , 'until" , the “acetone” wipe down !!

Have been out paddling for the weekend and I didn’t see this post till today.

I suspect that the oldest Dagger I still own is a Legend probably circa 1990. That boat has not had the slime disease. I also have an Impulse, made perhaps one or two years later, which was affected, but I was able to remove the crud with acetone.

By the way, I tried detergent soap, bleach and mineral spirits first on that boat and they did not work.

I think you are right
I believe that in many cases this residue is a result of oils that weep to the surface and then oxidize on the vinyl layer. Sometimes there is discloration that looks like mildew, but I’m not sure it is.

I have used acetone or MEK on Royalex hulls many times, probably hundreds, and never damaged a hull with either. The most common reason I have used these solvents is to clean and etch the vinyl surface in preparation to glueing in D rings or pedestals or such. I have also used them to get off glue residue from Vynabond or contact cement that has been left after removing vinyl D ring patches, knee pads, or such.

They have to be used with care. If you dribble any into the hull, it must be wiped up immediately. Prolonged contact of the hull with these agents will result in hull damage. They should not be applied to any areas of damaged hull where the ABS foam core is exposed. But these agents evaporate very quickly. They can be applied to the surface with a moistened cloth and will be long gone before any hull damage occurs, if care is used.

I do generally wash the hull out with detergent soap and water and rinse well after using these agents, though.

the only other thing I can add …
… but i’m sure you know this pblanc , is that some type of protective glove (rubber,nitril, etc) should be used when handling such … I started with plain ol latex disposables but they are cheap and tear quickly .

The thing I wanted to say was , the weather was cold and my hands quickly got very cold because of the evaporation factor with the acetone and prolonged use time with it … I switched to a heavier (industrial) glove and used a pair of cotton Jerseys under those first . Maybe call it an acetone drysuit for your hands , lol .

That made all the difference in comfort … no more freezing hands !!