Monday, 18 April 2016

Auntie Fouling to the Rescue

Dear Auntie Fouling

Spring is here and my bottom is a disaster!  There is so much advice out there about how to get it in shape - how do I know what’s right for me and my bottom? 

More specifically, I have just bought a 25-year old Catalina 25 lifting keel with, I would say, 25 years of bottom paint still clinging to the hull, judging by the layers of colors I’ve found so far. 

I know I have to scrape until I get all of the old paint off, but how do I know when to stop?  And then what?  Do I need to prep the surface or can I just slap the paint on?  And which paint?!  I’m tending towards the really expensive stuff because I want to do it right, but I’m just not sure what’s right for me. I also read that these bottom paints are toxic and that I should suit up for the Apocalypse. What’s up with THAT? And how many coats of paint should I use? And do I need to do something in between coats?  

Signed,
Bummed about my bottom


Dear Bummed,

If you ask 3 different people how they clean their bottom and apply bottom paint, you’ll get 5 different answers. Confusion is just part of the fun of being a boat owner and you must learn to embrace it.

Scraping your bottom:  yes and no.  (See how much fun this is going to be?)  Ideally, you should try to get as much of the old paint off as possible, but you must keep in mind that your goal is to have a smooth bottom.  If you’ve got pits and rough spots, those need to go.  Usually your epoxy layer is a white or cream color, and as far as I know, no one makes bottom paint that color, so stop when you strike white (or white-ish).  If getting down to the epoxy layer is a massive job, just aim for smooth.  Buy a quality scraper with replaceable cartridge blades. These babies cut through old paint like a hot knife through butter.  When you’ve got things as good as you can with the scraper, pull out your orbital sander and have a go at any uneven spots.

A note about safety:  Bottom paints are toxic to aquatic scum, and very bad for any of your soft tissues, specifically skin, eyes, lungs, etc.  One of the biggest dangers is from the fine dust while you’re sanding the old paint off the bottom.  Before we learned how to suit up properly, we suffered lung infections and eye infections from bottom paint dust and we hope you’ll learn from our mistakes. Tales abound of reckless people eschewing masks who ended up in the hospital for months with severe lung damage, so please take the warnings seriously. 

What's hot in boat-yard apparel for 2016.

When scraping and especially while sanding, cover your eyes, nose and mouth.  Those little filter-type masks with the metal nose clip and elastic bands are, in my humble opinion, good for NOTHING.  They’re hot and sweaty and have gaps in them and make you itchy and miserable.  The best method we’ve found is to take an old tee-shirt and pull it down over your head until it stops on the bridge of your nose and on your ears.  If the sleeves are long enough, tie them behind your head.  Bonus points if you take a magic marker and draw a big smile around the mouth area.  Friendly suggestion:  brush your teeth well before putting on any mask.  You’ll be mouth-breathing in close proximity to your own nose.  Trust me on this one.  For the eyes, use wrap-around eye protection that you can get from a hardware or garden store, not sun glasses with open sides.  When it comes time to paint, cover your skin to minimize contact with the fresh paint (plastic gloves, long sleeves, pants).  Don’t forget a bandana or cap for your hair.  If you have a choice, it’s good to do the painting on a breezy day when the fumes will be whisked away.  See also “Clean Up” below.   

Preparing to paint:  Now you have a smooth bottom and are ready to paint.  Wipe the bottom down with a damp rag to get rid of the dust. Tape off the zone to be painted around the water line.  Do NOT use masking tape.  Once it bakes in the sun it’s very difficult to get off.  Use the plasticky pvc-type tapes for this job found at any boat store.  Bottom paints need to be stirred well before you use them.  Use a stirring stick or paint mixer attachment for a drill and mix for several minutes.  You may need to remix every hour or so if you see any separation occurring.  Read the can for instructions for your particular paint.  Most paints will lose their anti-fouling properties if they are exposed to air for more than 3 weeks, so you should only start painting when you know the boat will go in the water within the time delay.

But wait !  Which paint ??:  This all depends on your bottom, what kind of sailing you do, where your boat is berthed, what kind of water it is in, what the last type of paint applied was, how well you removed (or didn’t) the last coat of paint, and how much money you have.  In general, if you are taking your boat out of the water and re-applying bottom paint every year (as you should), you do not need to do anything fancy.  There are two basic flavours:  hard matrix (modified epoxy paint) and ablative.  The biocide in the hard matrix gets leached out over time but the paint layer stays more or less intact.  It dries to a hard smooth(ish) surface that doesn’t wear off.  The ablative paint slowly wears away, exposing fresh biocide at a regular interval and the paint itself erodes with time as well.  If you sail a lot of miles or if your boat is berthed in an area with a strong current, an ablative paint will wear away quickly, but the advantage is that it’s easier to remove for the next season’s paint job.  The hard matrix will provide continual protection but eventually the biocide will be gone and you’ll just be left with paint and algae, and a bigger mess for the next season.

We have always used hard matrix.  For the way we sail, it lasts longer, it’s cheaper, and we scrape and repaint every year.  This year, however, we’re doing something different.  We’re heading into the Med and we’re not sure we’ll pull the boat out of the water or not for 18-24 months.  We need long-lasting protection.  The Jeanneau boatyard guys suggested the following one-two punch:  hard matrix as a first layer, then ablative as a second layer in a different color.  The ablative will slowly wear away to expose the hard matrix, which will then take over as the ablative fades.  With the color differences, we’ll be able to see the “wear” zones and can judge how quickly the ablative is ablating.

1st coat, hard matrix in grey.  Note red pvc tape at the water line.

Final coat, black ablative.

For you, Dear Bummed, I would suggest 1 good layer of hard matrix.  Your boat is berthed in brackish water in a river exposed to current, and you tend to haul out at least once per year anyway, so no need to go overboard (so to speak…) with fancy high-copper content paints.  Go for plain hard matrix.

Painting:  We like small rollers for applying an even layer.  Use cross-hatched passes to cover an area.  If you want to impress, you can finish the last pass of the roller in the direction of the water flow, which, in principle, may give you an additional 0.1 knot of speed. It’s a long boring job and you may as well amuse yourself.  Start painting the keel and the underside, then paint your way up and out to avoid getting paint on your hat or bandana when (not if) you bang your head. (Hey, you already look pretty silly with that tee-shirt pulled half-way down over your face – why not add an old bicycle helmet to the costume?)   

If you choose to do a 2nd coat, read the can for instructions about drying times.  If you put the 2nd coat on straight away, you can just put it on directly over the 1st coat after it’s dry.  If you have to wait for a few weeks between coats, you will no longer have a chemical bond with the 1st coat and will have to make a physical bond for the 2nd coat, which simply means a quick pass with fine-grained sandpaper (HAZMAT clothes and mask again…).  You want to have a little bit of paint left over to cover the patches under the cradle or trailer that you can’t reach.  Do this just before the boat goes in the water – it doesn’t need much drying time.  If you’ve got quite a lot left over, take another pass along the water line, which is where most of the algae will build up.

Note: this should go without saying, but I’ve seen it happen.  Do NOT paint your anodes, folks.  Think about it. 

Change anode.  Do NOT paint it !

Clean up:  Take the tape off as soon as you finish your last coat.  Don’t let it stay on until the paint dries or you risk pulling off flakes.  Dispose of everything as directed on the can.  For any spills on the skin, you can use paint thinner (or gasoline) to wash it off, but hop in the shower as soon as possible and scrub down well (loofa, sponge) a couple of times to “detox”.  Don’t forget the inside of your ears.  That fine dust can find its way into the darndest places.  Rinse eyes as needed with water or a saline solution.  For your nose, netty pot, netty pot, netty pot. 

And now the most important part: no matter how careful you were with the mask, etc., your nasal passages and throat have probably been assaulted.  The best thing for you to do is to pour yourself a large icy gin and tonic.  The ice soothes, the bubbles dislodge any lingering particles, and the lime and gin disinfect. You may need several applications of this phase, but your health is no place to cut corners.     

9 comments:

Ellen @ The Cynical Sailor said...

This is a great post! I love how you made a discussion of bottom painting (yawn) hysterical AND interesting!

Cheers - Ellen

Sailing Mareda said...

Thanks Ellen ! Coming from you (e.g., the mistress of funny boating posts) this really makes my day. That and finally getting all the paint out from under my fingernails...

Keith & Nicki Davie/Dunbar said...

Great post, but with on thought on safety equipment: The Tee-shirt over the head idea is stylish and basically free, but it's really not safe. I don't know what the micron-size of a tee is, but I guarantee it's not small enough to stop the dust from your sanding completely - and as you pointed out, you want to stop it all - that stuff is nasty.
Instead, spring for the $40 USD breathing mask with chemical cartridges or - better yet - the $110 USD full-face mask that covers mouth, nose, eyes and face completely and filters out all dust and solvents. Yes, it's an investment, but really - it's your health we're talking about here, and it's cheap on that scale.
Great post beyond that little thing!

Keith & Nicki Davie/Dunbar said...

Oh, and note that there are a number of water-based ablative paints out there now, some rating quite good - so no solvents needed for cleanup, and less noxious fumes, too!

Sailing Mareda said...

Thanks for the breathing mask ideas, Keith and Nicki Davie, and you are right to point out that this is serious business. The tee-shirt on a windy day does an okay job, but I do still get some particles coming out of my nose with the netty pot washes. We'll see how our ablative holds up this year and I certainly hope the clean up next year will be minimal.

LittleCunningPlan.com said...

Yes, great post! We need a bottom job on Galapagos. Our last boat was 34 feet. We did that one ourselves. My shoulders already hurt when i think of sanding the bottom of our 47 foot behemoth. I wonder if we can pay someone to do that? Oh, right. We're supposed to be saving money. I'm sighing heavily as i type.

Astrolabe Sailing said...

Lol love this post! Great idea with the hard vs soft antifoul as well. I hate this job!
What are you using on the sail drive? We cant use the copper based antifoul on the saildrive as it will eat it, so we have to use some other non-copper stuff which really doesn't work very well.

Sailing Mareda said...

Thanks Little Cunning Plan. I don't want to demoralize you, but my arms definitely felt the difference between 34 feet and 37 feet ! Granted, Mareda is also much wider than Spray was, but I was really surprised at how much harder it was. Maybe I'm just getting older and flabbier. I, too, had the brilliant idea of paying someone, but we are also on a budget.

Sailing Mareda said...

Thanks Astrolabe ! We used the same anti-fouling on the support part of the saildrive down to the anode connection, but didn't touch anything from the anode to the propeller. The propeller part is already treated with something (?) and the boatyard guys said it wasn't necessary to put anything on it. I don't think our paint is very high in copper (mostly the cheap stuff). I hope we won't have any bad surprises ! I'll let you know next year...