What is this substance?

[Skoot1123]

Hey Ballers - I have a question about a substance on the bottom of our boat. I noticed this summer a bit more oxidation on the sides and decided to get serious about removing it. In process of buffing the rest of the boat I thought it would remove the stuff on the bottom, but it has proven otherwise. The best description I can think of is that maybe it is dried wax? If I take my fingernail and scratch it the white substance flakes off and the gel is nice and smooth underneath. Any ideas for what it might be and how best to remove it?

Thanks Ballers!

[MISkier]

Maybe try some CLR? Could it be lime deposits?

[oldjeep]

Not sure what it is, but I would just use some Collinite 940 fiberglass boat cleaner and follow it up with a couple of coats of 885 fleetwax. That combo keeps my mostly black boat shining, ought to work fine for red. If it doesn't come off then you have not applied enough elbow grease with the cleaner.

 

[Skoot1123]

@MISkier - that is an interesting idea. Our lake water could be a contributor to that and the lake that the boat was previously in could also exacerbate that.

 

I did spray on some Starbrite instant hull cleaner this past Saturday. It did help break it up a bit and turned it whiter, so I think it did work. I have some Mary Kate On Off Gel coming as well. Maybe that will cut it further or altogether.

 

@oldjeep - ah, I have heard of Collonite 940. That may cut it pretty good. Your boat looks fantastic. There are also some “spots” on the sides that are pretty stubborn. For buffing I have been using buff magic. Seems pretty good so far, but would be even better if it could solve the spotting issue. Unfortunately those spots don’t show up in pictures.

[oldjeep]

What are you buffing with - hand power, orbital buffer or a high speed buffer? For tough stuff there is pretty much no way to remove it with hand power or a $25 wax buffer.

[swc5150]

Try Lime away. I agree that looks like lime residue.

[ALPJr]

Try some elbow grease

[Skoot1123]

Buffing is being done with a Rotary Pro Shurhold polisher. I would definitely recommend this variable speed rotary buffer, prior buffing experience recommended. Once this stuff is knocked down then I can finally make the boat shine like I want it to.

[swc5150]

I learned the hard way to remove lime. If you have the time and will, and determine this is in fact lime, sure you can elbow grease it away. Or spray Lime-away on it, give it minute and wipe away. You can do the entire boat in very short order. It doesn't need to be hard:)

[Skoot1123]

@swc5150 - whole heartedly agree. I know I can scrape it off but the time that takes is not time I want to spend.

 

That’s one reason why I bought the buffer - have the machine do the tedious work.

[cougfan]

@Skoot1123 like the old saying says “ work smarter not harder “ ?

[oldjeep]

I personally stay away from spraying any form of acid on the hull. Seems to leave the gel in a state where it is more likely to pick up and hold skuzz.

[Skoot1123]

@oldjeep - Interesting. Hopefully your hull hasn’t been as dirty as mine is at the moment.

 

Any layer of scuzz on the bottom/sides of the boat would in my opinion act as slight buffer for the gelcoat when doing the acid wash/rinse chemical work. Once the acid/chemical is washed off you for sure would want to get some type of protectant on the hull right away. For me, I’ll be doing a three stage buff/wax/polish. The polish will keep the surface smooth and make it less prone to additional scuzz. Has your experience been different than that?

[rockdog]

If above fails - wet and dry then polish, wax etc.

[skiinxs]

+1 on using Lime Away or CLR. If it was light, vinegar would do the trick and after removing it, in the future wipe downs with 50/50 vinegar / water after every use will keep the lime off. No reason to subject your gel coat to hard buffing, especially when that is pretty ineffective, when a simple spray -on, wipe off will do the trick. Lime away or CLR will not hurt the gel coat.

[NameUnavailable]

I skied at a lake in OKC that had hard water. We used hull cleaner which is an acid to take it off. You will need to wear gloves, and it will be on the bottom too. We never cleaned that as much. Then wax it. It will come back depending on wipe down method you use will tell how long it lasts.

[oldjeep]

@Skoot1123 - yes, in my experience the acid does something to the gel coat that makes it either more porous or rougher, causing it to get skuzzy faster. Best bet is to just keep it clean and covered in a good coat of wax all the time. If you have hard water, use something like Marine 1 wax as you dry as a wipe down. The water I boat in is pretty hard and you get white water spots all over the boat without it.

[richfoster]

@NameUnavailable - I skied at that lake. I think it was called “NameUnavailable Lake”. The cleaner we used was Zing. Definitely wear gloves. We didn’t use safety glasses but we should have.

[Skoot1123]

Going to try the CLR on the hull and see how that works. Hoping to get the crud off and have smooth gel again.

 

As everyone should know - take the necessary safety precautions when dealing with chemicals.

[skiinxs]

Another good tip, a friend has been getting to my lake early to ski a few times a summer and putting one of the newer ceramic coatings on my boats. With this stuff on the fiberglass, I have been able to ditch the vinegar and wipe down without it after hanging the boat each day. I never get any water spots any more and the stuff is really slippery, easier to wipe down. I used to be a big advocate of using 303 on the gel coat, but I believe this stuff is better.

[KRoundy]

@skiinxs Brand name of that ceramic coating, please? There are a lot of “ceramic” coatings on the market, and I’m sure there are some that are good and some that are junk.

[skiinxs]

I was afraid someone was going to ask... and I don't know the answer. I'll check and post as I hear back.

[Skoot1123]

Well - I used some CLR on the white substance seen in the picture on the running surface of the hull. Didn’t do a thing to it. Certainly a head scratcher to me. Any chemists have some insight?

[swc5150]

Try vinegar. It's cheap and you prob already have some in your house.

[Sethro]

That's not even the water line, is it? And you don't leave it in the water I'm assuming anyway? Does it wrap around to the underside of the hull too?

[skiinxs]

@KRoundy It was a ceramic coating from Mothers.

[Skoot1123]

@sethro - it does go all under the boat. I would say what shows is a tiny bit under the water line. Our usual procedure is to wipe the boat down after every use. (Sits on a cradle out of the water). It really is a curious thing. I used some distilled vinegar this evening and that didn’t take it off either. I am thinking there are now two options: Mary Kate On Off Gel and a wet sand of the hull. Sure hoping On-Off gel can take care of the rest.

[A_B]

I would try Bio-Kleen Fiberglas and hull cleaner spray before I would start any buffing wheels. It has removed red clay water stains on white hull amazingly well. Doesn’t impact the gel coat and easy to wax back to shiny finish.

[Nater]

Try blue liquid Toilet Bowl cleaner......It’s Like Magic!!

[Skoot1123]

@nater - tried that too. I don’t think the acidic concentration was strong enough at 9.5%. We’ll see.

[skiinxs]

I have had success with StarBrite hull cleaner helping a friend clean a boat that was left in the water for long periods of time. I sure thought by your picture that yours was calcium, but if it was the CLR would have removed it.

[Skoot1123]

@skiinxs - yeah I thought so too based on how hard it was. But it didn’t do anything. Once I figure out what it is and get it clean it’ll be like a brand new boat when I’m all done. I’ll be posting some pics.

[swc5150]

X2 for trying Starbite. But wear gloves and eye protection, as that stuff burns. Works miracles though. That’s my “after all else fails” go to.

[6balls]

star brite hull cleaner. No elbow grease. Put it on with a sponge just working along and the stuff you applied it to just starts to melt away as you move along, so double back quickly and rinse copiously. Once all done wax her up.

If that doesn't take off whatever you have there--shoot I dunno.

[markn]

Simple, quick test. If it is calcium carbonate (hard water that evaporated to dryness and accummulated) if you apply an acidic solution (muriatic acid, phos-acid which is lime away) and it "dissolves or fizzes or bubbles, then it is a mineral salt. If you apply an alkaline solution (caustic) and it comes off, if is organic. Acids do not clean organics and caustic solutions do not clean mineral salts. Based on the pics, it is simply calcium carbonate. Lime Away will dissolve it easily. Just give it a good rinse after cleaning. Phosphoric acid is a pretty weak acid and will not hurt the Gelcoat. Good luck.

[Skoot1123]

Well folks - finally - after trying a lot of different combinations and frustration I bought some straight muriatic acid from Ace hardware. Started spreading it around with a rag and felt like it was doing something but to be sure I had to pull the boat out of the barn. Out in the open I sprayed it on a small spot to see what it would do - it fizzed like crazy! Not sure why there was such a difference between spraying vs wiping it on but there was. Finally - after a couple hours I have a nice and pristine looking hull.

 

 

 

[BraceMaker]

@Skoot1123 rinse your trailer then do it again then spray a mixture of baking soda and water on the trailer and rinse sgain. Same for the floor.

[DangerBoy]

Sorry, I didn't see there was a second page so I wrote a long post saying it's dried algae/biofilm and you'll need to use a strong acid to remove it. Most boat hull algae removers contain phosphoric and/or oxalic acid. I used Muriatic like you did but I diluted it 50/50 with water.

 

I don't think using baking soda to neutralize the acid is necessary. Just spray everything down hard with a pressure washer using lots of water to dilute the acid and you'll be fine. ;)

 

 

 

 

[DangerBoy]

To prevent that sort of buildup from ever returning, I wax the hull every spring and then wipe the hull completely clean of biofilm using rags and a bucket of water every time I pull the boat out of the water on its trailer. Never give that crap the chance to dry on the hull. It's super easy to clean off when the boat has just come out of the water; it takes way more work to get it off once it's dried on the hull.

 

My old boat was 40 years old when I sold it and the underside of the hull stiĺ looked great because I followed the above regime every year without fail.