Preparing Totem for Coppercoat

Two girls talk next to a sailboat on a hardstand.

 

Coppercoat’s advantages in durability (=savings!) and environmental friendliness (=how we live!) have made me more excited about antifouling than I believed possible. As if to complete the picture, Totem’s shiny new metallic hull is dazzling in the Sonoran sun. Once sanded to activate the copper the hull will oxidize to rich shade of verdigris, but for now it is stunning. Applying Coppercoat was an intense day of work, and an even bigger effort to prep. Researching our options confirmed how critical good prep is for this unique antifouling to be effective: here’s what we did, and why.

Two men scrape paint off the bottom of a sailboat
Jamie and Rudolpho tackling the bottom in June

  

Prepping for Coppercoat: two people examine the hull of a boat on a hardstand.

1. Stripped. Bottom paint and barrier coat were stripped to bare fiberglass last June, shortly after getting hauled in Puerto Peñasco. Totem didn’t have gelcoat left, the surprise that greeted us after blasting decades of accumulated bottom paint in Grenada. We painted on paint stripper, and scraped it off; not a perfect job of paint removal, with some visible bits in the valleys of Totem’s not-very-smooth hull, but sufficient for the summer. Boats with different substrates (e.g., gelcoat, metal hulls, etc.) get different prep.

2. Dried. From June until November, Totem’s wet hull dried out on the hard in the Sonora, Mexico. That’s Sonora, as in The Sonora Desert, where heat and low humidity provided an ideal climate to dry out during the summer months. Elsewhere (like the US east coast, or mainland Mexico, or further south) would have taken many months longer or required additional equipment (e.g. heating pads) or both.

Hull moisture meter readings were around 25% when we left. Eight blue-tape boxes were masked off to ensure repeat readings were in the same location; during our five months away, Cabrales Boatyard manager, Salvador Cabrales, would take periodic readings. He’d write the new measurement on the blue tape, then send a photo of it for us to see. Great peace of mind on progress while we were remote! The readings were at 6% to 7% at the end. During the drying period, the boatyard pressure washed the bottom to remove glycol, the sticky byproduct of a Polyester / Vinylester resin and a wet hull, that migrates to the surface as the hull dries.

 

A man writes on blue tape affixed to the hull of a boat.
Salvador updating measurement on the blue-tape reading area
Excel chart showing hull moisture readings declining over time
Homeschool bonus: charting the readings over time
Moisture meter showing reading.
Lower every time!

3. Stripped again. Totem’s bare hull was a rough surface, with flecks of paint remaining in the crevices. Brushing on paint stripper (we used Aquastrip) softened the remaining paint, which came off completely with a pressure washer.

Man brushes paint stripper on a boat.

 

Man powerwashes the bottom of a sailboat.

 

4. Sanded. The entire hull was sanded with 80 grit. After a full day of holding a vibrating sander mostly at or above shoulder height, Jamie hired a couple of guys from the yard crew to speed the job along and save his back.

Man in tyvek suit and face protection sanding a sailboat hull.
These guys helped a lot, but Jamie’s basically been in pain at night for a few weeks. 

  

5. Epoxied. If you’re at bare fiberglass, like Totem, the substrate (fiberglass) is porous and rough. After was wash and acetone wipe down, one coat of West system epoxy went on. When it was tacky, a second coat of West System with 410 micro-balloon filler to thicken the mix to work towards a smoother surface. Adding another layer of epoxy on top of a tacky prior coat is called hot coating: this creates a chemical bond between layers. The alternative is curing between coats and replying on roughing up the surface for a physical bond.

Three people measuring up epoxy to roll on a boat.
Mairen and Siobhan help mix up epoxy

 

6 – 9. Cured, sanded, washed, then wiped with Acetone. Epoxy was given a few days curing time before sanding. Sanding the thickened epoxy coat greatly improved substrate smoothness. Washing the hull got rid of the dust, and wiping with Acetone prepped for the next layers of epoxy.

 

Two people wipe rags on a sailboat hull while wearing heavy gloves
Wiping on acetone. Every once in a while need to demonstrate that I am not just behind the camera! 

 

10. Epoxied again. Several times actually: three coats of West System (two with 422 barrier coat additive) were applied to Totem’s hull bringing the total to five layers of epoxy, minus the 80 grit sanding.

Man in respirator with sander working on hull.
Looking pretty shiny after all the West Systems was applied! Fashion by Goodwill of Phoenix.

 

Siobhan uses a sharpie to mark rough spots that need more sanding; evening guard, Federico, looks on.

 

11 – 14. Cured, sanded, washed, and wiped with Acetone…again. Very intimate with the surface area of Totem’s hull at this point.

Drying the hull after a last rinse before the barrier coat went on.

  

15. Barrier Coat. Three coats of Interlux Interprotect 2000 were applied over the West Systems. Interlux recommends five coats, but with five prior coats of West System (including two with barrier protection additive) we feel confident that the combined eight coats will serve.

Three people work together to apply Interlux barrier coat to a sailboat hull.
Barrier coating as a family affair: Mairen stirs, Jamie and Siobhan roll on.

  

16 – 18. For the third time: cured, sanded (lighter, much lighter), and wiped down– but this time, no acetone! The hull was dusted with rags instead to remove debris from sanding, and leave a surface primed for Coppercoat. For future Coppercoaters, we have done even better to gently pressure wash one or two days in advance.

Consumables list – I’m probably forgetting something:

  • gloves – decimated a box of 150, plus a half dozen heavy-duty pairs for paint stripper
  • 80 grit disks – 175
  • 320 grit disks – TBD
  • paint brushes – 4
  • 3/8″ roller covers – 10 (Interlux Interprotect 2000)
  • 1/8″ roller covers – 6 (West System epoxy)
  • Acetone – 3 gallons
  • blue tape – 1 big roll
  • rags – large bag of clean, lint-free rags
  • mixing sticks – 20
  • spreaders – 10
  • Aquastrip  – 5 gallons
  • West System – 4 gallons for 5 coats, plus 410 filler and 422 additive
  • Interprotect 2000 – 7 gallons for 3 coats

A note on safety equipment:

Toxic stuff is all over this project. One of the reasons we’re excited about Coppercoat is how environmentally friendly it is, compared to alternatives, but getting to that point is not – really, a lot of boat work is pretty nasty, and this prep is no exception. Take care of skin, eyes, and lungs!

My friend Kate Laird (Check out her expedition sails and homeschool expertise!) called out safety kit shortcomings in some pictures posted, and she’s right. We should be better about how we’re protecting ourselves, and I also seemed good at capturing moments when we weren’t! Here’s an equipment list to help with planning ahead, with products we like.

Kate Laird from Seal expedition sail sanding paint on her boat's hull.
Kate- or is that Hamish? Or one of their teenage daughters? Working on the hull of their expedition vessel, Seal.

Respirator: Jamie and Kate both like this 3M 6200 half-mask. Bad luck was the straps on Jamie’s broke just before we started. You can get replacement straps and other parts – it’s one of the nice things about the respirator.

These reusable respirators have filters for particular matter (these pink ones) and VOC fumes (white ones here). Hot tip from Kate: keep the VOC filters in a ziploc bag to extend their useful life. They actually keep filtering away in there!

Jamie decided to try these disposable Moldex-Metric respirators this time. They were easy to source, lighter weight, and relatively comfortable. However, they’re really for “nuisance levels” organic vapors vs. fumes of OSHA PEL standards.

Skin protection: Tyvek jumpsuits are the standard, and they did get modeled around Totem, but the Goodwill in Phoenix turned out to be a good place for quick, affordable cover-up (50% off on Saturdays, and help from the Jollydogs crew picking things up for us!). We needed a few warm layers, anyway: we were NOT PREPARED for cool weather here in the late fall, and didn’t have clothes for it. Jamie’s happy: he hasn’t had a single day of gritty itchy boatyard yuck.

Eye protection: Jamie wears glasses but adds goggles over them when he’s worried about exposure. We picked up inexpensive eye protection in a hardware shop in Peñasco that worked fine for the girls. For more souped-up protection, this full-face respirator (3M 6700) Kate recommended is gold standard: big, single lens for easy viewing.

Further note on toxic junk, and being outside the US: I don’t know if there are any standards for the toxic waste produced in boatyards but the practices here mean we’re doing work that wouldn’t be handled the same way in the USA. Some things can be addressed by individual boaters, with some planning ahead. A shopvac using HVAC filters to capture and dispose of dust off sanders (Jamie’s got a bag on his that he’d empty regularly, and dispose – amazing how much of that stuff comes off – but no special filtering). You couldn’t just paint on stripper and pressure wash it off on a hardstand spot like we are, but set up for catchment and hazardous waste dispo…no, actually, you probably couldn’t because there’s probably not a hazardous waste facility. In the US, you’d stage the boat for this at a place where runoff is captured. For the most part, our lives are an incredibly light footprint environmentally: every once in a while, they’re really not.

Totem has 12 coats of epoxy right now. TWELVE. OK, so some got sanded off in the process, but even if we lost a couple of coats – it’s a long way from the bare fiberglass that peeked out when we blasted at Grenada Marine last year.

Coppercoat application: next post.

Wet bottom: a haulout story

boats anchored at Isla Danzante Baja

Totem cruises the Sea of Cortez;  in about three weeks, we haul at the Cabrales shipyard in Puerto Peñasco, a small harbor surrounded by the Sonora desert. Typically, boats can go a few years between haulouts. So why now – didn’t we just do this in Grenada, six or seven months ago? Yes, we did, and had an unpleasant surprise. This is the backstory, and what we’ll do about it in Peñasco.

At the time we hauled out in Grenada Totem had gotten nearly three years out of the bottom paint applied in Thailand. That’s a good lifespan for ablative! We chose Grenada to repaint (a relatively safe hurricane season location, affordable rates, cruiser-friendly boatyards). Not only that, but in Grenada we had an opportunity to do a “proper” bottom job on Totem.

Prior to hauling in Grenada, we put on three bottoms on Totem in ten years, representing at least 11 coats of paints and primers and barrier coast. That’s on top of who knows how many layers we bought the Stevens 47 then called “Don’t Look Back.” Even then the hull wasn’t very smooth; over the years, accumulation of bottom paint became progressively uneven. By sand blasting the bottom back to the original barrier coat over Totem’s gelcoat bottom, we’d be able to start fresh. The crew at Grenada Marine would help us get it done right!

sailboat in travel lift slings

Totem gets hauled at Grenada Marine

Blasted surprise

To take down the old paint, a specific grade of sand is used; it’s mixed with water into a slurry that’s blasted at the bottom. This removes paint without damaging gelcoat or epoxy barrier underneath. Except what we found underneath the paint was a big surprise: there was no barrier coat. There was not even gel coat. Just bare fiberglass hull.

fiberglass sailboat hull

Bare fiberglass: not what we expected under the paint

The crew sandblasting stopped work to inform Jamie. I’d like to say it was to inform me, too, but I was happily internet-ing away with wifi in Grenada Marine’s lovely open-air waterfront restaurant. But this discovery… it wasn’t really good news. It wasn’t what anyone expected. The only thing to do was remove the rest of the paint, evaluate the bottom, and then decide on the next steps.

Why bare fiberglass?

We suspect Totem had a big problem with osmotic blisters somewhere in her history. Os-whaaa? Osmotic blisters are bubbles on the hull caused by a reaction between salts (from absorbed seawater) and styrene (a chemical in the fiberglass resin). This reaction causes pressure which can be great enough to push outwards between the fiberglass hull and gelcoat outer skin, creating a bubble (or, blister).

It can also happen pretty easily deeper than the surface: when fiberglass boats are made, they’re mainly constructed from heavy-duty fiberglass roving. But the outermost layer is usually thinner/lighter, to provide a smoother surface so that the last layer before gelcoat is a gentler transition to a smooth outer hull. Because that’s a thin layer of fiberglass, in bad cases of blistering this layer can be affected too: it can create voids by pushing out in that last, lightweight layer of fiberglass. (Side note: we’re not chemical / material engineers; this is just our understanding!)

sailboat without bottom paint

Naked hull

We suspect Totem’s problem had sufficiently bad blistering that a prior owner did what’s called a full peel. That’s when all the gelcoat is removed (peeled), and the hull is allowed to dry (hopefully) to resolve a blister problem. The bottom is then rebuilt by adding a new, thin outer layer of fiberglass and a two-part epoxy resin barrier coat over the top of that.

The crew working with us at Grenada Marine murmured approval at the fiberglass hull. Whoever did it had done a nice job, and they appreciated a good layup. The question was: would the fiberglass be wet? Or dry?

It’s a bigger problem

When blasting was finished and we were waiting for Totem to dry from the wet slurry, Jamie was cautiously optimistic that the bottom wasn’t wet. We really hoped it wasn’t, as this signaled the need for more work and more expense. But the crew supporting us, who we had come to trust for knowledge and judgement, looked at Jamie and said – “I know it’s wet.” How? In even that brief waiting period, he pointed out a sheen on the hull’s surface. This was a sticky, shiny film that is a result of the reaction between the salt and styrene. That only happens if there’s moisture in the hull. Subsequent readings on a moisture meter over a period of days confirmed his observation.

Why did it happen?

The crew may have appreciated that fine layup, but we still had a problem. Well-done fiberglass work aside, there were two unknowns in that job which lead to the moisture problem we faced.

First, we don’t know what kind of barrier coat as applied. We can tell it wasn’t a two-part epoxy resin; we’d have seen that layer that when sandblasting. We could hope that that outer layer of glass was correctly done, but we don’t know.

Second, we don’t know if moisture in the hull which caused the blisters had been dried out before the repair was made, or if there was still moisture absorbed in the hull that got covered over. What we had left is a fiberglass bottom without a gelcoat that would shown blistering from remaining moisture, so we can only speculate.

jackstands supporting fiberglass sailboat

Excavating Totem’s bottom

Somewhere between these missing links of information, Totem’s bottom became a wet hull. Jamie suspects the hull wasn’t wet initially, but has happened over time under our ownership due to the problems with the earlier repairs. Why? Because for our first years of ownership we always floated high on our waterline, and in recent years, Totem has sat relatively low on her lines. OK, OK, we have accumulated trinkets on board and the kids have gotten bigger and there are probably a few more items in lockers than when we moved aboard in May 2018! But these would not add up to the mass required to sink Totem to the point where our stern end has settled down to (and even slightly below) the waterline. Most likely this water weight has slowly accumulated over time.

Now what?

We were reluctant to bury the wet hull under more paint, but had few options. The hull needs time to dry out, Grenada’s humidity and rain makes it a poor choice of location. On the other hand, we had plans to sail for the Pacific coast of Mexico. Where better than the dry desert of Baja, already our anticipated destination for hurricane season? So thin barrier coat and two thin coats of ablative bottom paint were applied: enough to get us to an ideal place for drying out a boat, the low humidity of the Sonora desert. These thin layers are already thinning, which we hope makes the job of going back to bare fiberglass for a proper dry-out an easy one.

Totem will sit on the hardstand in the desert while her crew spends a summer back in the Pacific Northwest. A periodic rinse is good and the rain there is measured in millimeters, so a periodic hose-down to help pull out impurities and styrene will be hired out in our absence. We’ll be back in the back half of October after the Annapolis Boat Show. HOPEFULLY, at that point, the hull will measure dry; then the work to put it back begins. Fairing the hull. Adding multiple coats of two-part epoxy barrier to keep water out. Starting fresh, with new bottom paint.

Grenada Marine

We may have had disappointing news during our haulout at Grenada Marine, but the crew we worked with gets high marks. Part of our decision to haul there was the full-service staff. At other boatyards, you hire in contractors associated with the yard. On one hand, that puts the choice of workers solidly in your hands. On the other, being your own project manager adds risk and time (I’d prefer deal with one point of contact the yard if there are problems, rather than a handful of different contractors). We were allowed to mix DIY work in, which helped us save money on jobs we could do, and everyone who worked on Totem impressed us.

Grenada Marine team

Very happy with the team at Grenada Marine! Just before splashing with a shiny bottom

More on blistering

That’s the story of why we’re hauling out again so soon. Here are a few FAQs about osmotic blistering (and water ingress).

What does it look like?

Osmotic blisters can be the size of a coin, or much bigger – especially if the thinner fiberglass layer is what’s being lifted instead of a bubble of gelcoat.

What do you do if you have blisters?

It’s a question of magnitude: the size, quantity, and depth of blisters as well as the type of hull (cored or solid). Depending on the scope of the problem, they can be dug out – dried – filled, then repainted; if there’s time you can dry the bottom further, and re-barrier coat it.

When blistering is really bad, if you can afford it: peel the (permeable) gel coat, dry out the hull, and start fresh with a new barrier coat. Just, a more effective barrier than was apparently applied to Totem!

How do you dry out?

It’s pretty convenient that we have a low-humidity desert stop ahead. Grenada would have required intervention beyond sitting on the hard to sufficiently dry out. Heat lamps, heat pads, infrared lamps, and other options are available. Glad we can just park in the desert!

How bad can it be?

Osmotic blistering is partly a cosmetic problem of unsightly pox. Mostly, it makes a boat heavier. My dear friend Pam Wall lost 1,500 pounds of water weight absorbed in the hull of her beloved Kandarik, when hauled in Portugual for the better part of a year! This is mainly a practical problem for a boat that now sits lower in the water and may be slower. It can be behind some peskier problems than just making the boat weigh more, too We’ve also heard of dampness being felt on the interior, and potentially causing problems with mold/mildew.

Can the hull integrity be compromised?

Hull thickness, and strength of the layup in the materials, make it less likely. In a cored hull, water ingress can cause more significant problems. If the outer skin is thin, the blister and moisture in it can reach core material. Presumably that’s closed cell, but can still leech and lead to larger areas of delamination. Fortunately this is pretty unusual! Bottom line: it won’t sink your boat.

Further reading

An excellent guide to boat care with good information on the why and how of osmotic blisters, and deep details for DIY fixing (because wow, can this get costly) is Don Casey’s This Old Boat.

Totem and crew are enjoying stops along the inside of Baja on the way north to Puerto Peñasco.

Relaxing view from Grenada Marine's restaurant

Relaxing at Grenada Marine’s restaurant at the end of the day