Electrolytic and Galvanic Corrosion

Electrolytic and Galvanic Corrosion

Thursday 28 Dec 2023

Well if you have read the title … you have been warned! This blog entry may be a little technical and dry to some of you (i.e. incredibly boring). However, you might take some comfort in knowing that I won’t be discussing our battery capacity, as cruisers (men only) are apt to do at great length! Seriously, if you aren’t interested in marine electrical issues you might just want to take a quick look at the photos and move on.

As some of you know, for a couple of years now, we have been dealing with a problem of the anti-fouling paint “burning off” around the metal fitting on the outside of the boat. We were concerned that this indicated electrolytic corrosion, which can be a serious problem. It first became evident in Key West, Florida in early 2021 when a diver told us we had a “haloing” issue. We had the boat checked out by a marine electrician and he couldn’t find any issues and therefore, as we had never seen it before, we assumed it was due to stray currents from a faulty dock somewhere along our travels. However, the following year the same thing appeared to be happening so it was obviously our boat. We worked hard to identify the cause and then spent thousands of dollars at Safe Harbor New England Boat Works trying to address the problem. I’ll just say that we weren’t happy with their service and leave it at that. However, I thought I had pinned the problem down to a -ve battery cable that was not attached to the engine (as it should be) and, for the remainder of that season, it seemed like the issue was resolved. Prior to departing Morehead City in early November, I had a diver clean the hull and replace the zincs and I was distraught to hear that we once again had a “haloing” problem. In desperation, I wrote an email to BoatZincs, a company that specializes in making sacrificial anodes (zincs) and marine corrosion issues. I got a quick response from one of their experts, Bob Olsen, who said that rather than cover things in an email that we should chat on the phone. It was a fascinating and insightful conversation. He said that he had reviewed the data I had generated using a reference silver electrode (purchased from BoatZincs) and concluded that we do NOT have an electrolytic corrosion issue. It is simply a reaction between the exterior metal components and the copper in the anti-fouling paint because there is inadequate primer between the metal components and and the antifouling. He says that he handles half a dozen enquiries like this every year and that two coats of primer over the metal components (where possible) will solve the problem. The start of this issue does coincide with my re-finishing the underside of the boat and it’s quite possible I didn’t pay enough attention to this aspect, focussing mostly on getting epoxy barrier coat on the fiberglass areas. There’s nothing that we can do now except scrape barnacles off the areas where there is no longer any anti-fouling and address the problem when we haul out in the summer. 

I do want to give a shout-out to Bob Olsen at BoatZincs, he was amazingly responsive and helpful.

Bob commented that the values I reported relative to the silver reference electrode (-0.80 volts) indicated that the boat components are protected from galvanic corrosion (an unavoidable problem from immersion in salt water), but he also said that the main zinc was working really hard and suggested we use a larger sacrificial anode (zinc). We had a diver here in Jolly harbor look at the zincs and he replaced both the main zinc and the one on the end of the propeller. The latter was not a surprise as it is quite small and had been on there since June. However, the main zinc was 50-60% gone and had only been on the boat since the end of October. I don’t want to hire a diver every two months to replace it and so I need to find a way to extend the life. I couldn’t find a bigger zinc that worked with the current set up and I can’t change or add an additional through-hull fitting for a second zinc until we are up land, so I designed and built a system where I hang a second zinc off the side of the boat whilst at anchor and have it wired into the grounding system. The new zinc is big! I bolted it to an old plastic chopping board that we no longer use and attached a line and an electrical cable. I also ran a connecting cable up through the opening in the foredeck where the spare anchor chain emerges. Now I can just tie off the line, lower the cutting board/zinc over the side and plug together the wires and we have a second sacrificial anode in place. The boat reference values shifted from - 0.8 volts to - 0.9 volts, suggesting it does work, and I really think it should help preserve the life of our main zinc!

How fun is that? The most exciting blog post I've ever written!

Mike

This is an old photo (2022) showing the haloing around the grounding plate. You can't paint over this fitting (it is designed to ground the boat electrics and prevent lightening strikes). However, it does look like I painted right up to, and over, the edges of this bronze plate.

This was the new pristine main zinc on the underside of the hull, showing the impeccable anti-fouling paint ... prior to launch earlier this year (It's about 6 inches long, 3 inches wide)

The propeller and main zincs as they are now after being replaced by a diver (~6 months and ~2 months respectively in the water)

Here is the new extra zinc for deployment whilst at anchor. (~12 inches long, 2 inches wide and weighs maybe 5 lb). You can see why we no longer use that particular chopping board!

The new sacrificial anode (zinc) system hanging off the bow of Cotinga

This is what it looks like on deck, with the grounding wire emerging from the secondary anchor chain opening

Sharp Eye and Toot

Sharp Eye and Toot 

Wednesday 27th Dec 2023

Sharp Eye and Toot here logging on to tell you of our last ten days marine motoring to circumnavigate Antigua (pronounced An-tee-gah if you are local). We are here to share this with you in the form of superlatives:

MBF (Most Beautiful Fish): Constellation Glitter Fish - Also perhaps known as the Juvenile Yellowtailed Damsel Fish, but we like our name better. It is small and black to dark blue with iridescent blue spots that look like glitter and a translucent tail. 

Class President Fish: Sergeant Major - We loved how the Sergeant Majors would swim right at the top of the tall coral beds near the surface, right at eye level.

Most Likely to Break your Heart: Much of the coral seemed to be dead or dying. It felt like you were swimming through a graveyard at times. People - wear your reef-safe sunscreen and do what you can to slow down climate change

Best Meal: As for rules, we believe they are meant to be broken (when it makes sense and in this case it does). So we have selected a three way tie of Bouillabaisse, Chicken and Olive and Pancetta over Grits, Pasta Puttanesca with homegrown tomatoes and home canned sauce. Runners up: Rice and veg with egg and smoked salmon breakfast, Ham plantains and cabbage (Christmas Dinner), Butternut squash soup, Chili, Cassoulet, Pork Chops with veg and rice, Tuna with veg and rice, and Green Curry.

Best Beach: South Beach of Great Bird Island due to it having a tree where you could sit in the water while under shade - the optimal cooling method - only sacrificing taking on a few pounds of sand in your swimsuit bottoms. There was also some fun tide pooling where we found Chitons!

Brainiac Award: We first saw a pile of shells while snorkeling in Nonsuch Bay and remembered what we learned in ‘My Octopus Teacher’ (on Netflix) about how octopi often have shells outside of their dens. We dove down to inspect and sure enough! An Octopus was inside! Partially camouflaged to Sand color, but had some reddish color to it and you could see it’s eye!

The One That Got Away: Turtles - As it turns out, we’ve come to the conclusions that Turtles do NOT appreciate being called Turty Poo as we often tried to summon them with this name and though we saw many from the boat (especially in Ricketts Harbor - we tentatively IDed them as Hawksbills - Critically Endangered like most sea turtles), we saw none of them while we were in the water. 

Best Team Player: Once again, a two-way tie between Mike and Gloria for waking up at 5:30am to motorsail from Ricketts Harbor to Great Bird Island while we snoozed our little hearts out below deck until about 9:30am (We’ll blame it on the time difference). This generous act allowed us to sleep through the worst of the offshore swell and wake up once we had already reached calmer waters.

Best Luck: We had phenomenal weather the whole time. Not the best for sailing as winds were light, but perfect for calm anchorages with occasional light breezes to cool you down. 

Best Cocktail: Painkiller - Orange juice, pineapple juice, coconut cream, and rum with a dash of nutmeg. A Caribbean classic.

Best View: Shirley Heights/Block House - On Day 3 we went on a long sweaty, but beautiful hike to Dows Hill (including interpretive center with an informative and creative historical show on the history of the island), Block House had views of the east coast of Antigua with crashing waves below and a very welcomed breeze that was fun to catch in your shirt. From Shirley Heights you could see, Guadalupe, Montserrat, English Harbor, Falmouth Harbor and Nelson’s Dockyard.

Most Mysterious: We may or may not have seen a manatee from the boat during the passage from Jolly Harbor to Carlisle Bay (Or Carlile Bae for those Brandi Fans out there)

Most Likely to Surprise you: Southern Sting Ray - Although these giant rays (up to 4ish feet across) were quite spooky, they seemed quite friendly, gentle, curious and food motivated (something we can resonate with). And when they came out of our periphery, they still gave us quite the jolt! 

Most Magical Location: Ricketts Harbor (when nobody else is there) - On Day 4 we traveled from Falmouth to Ricketts Harbor. There was BIG swell from the Northeast and the passage was rocky and rolly. As soon as we cut in behind Green Island the swell died down and we cruised into Ricketts Harbor just as all the other boats left. We had the spot to ourselves overnight and it was magical to sit in calm water with turtles popping up all around and watch (at a distance) the big swells break on the shoals at the entrance to the bay.

Best Snorkeling: Hell’s Gate Dive Spot - On Christmas Day we both swam with stingrays and also went snorkeling near Hell’s Gate (a natural rock arch). The coral here was the healthiest we’ve seen off Antigua and the water was delightfully clear. Our highlight was seeing many rainbow parrotfish!

Best Shipwreck: A two way tie between this blog entry and the Wreck of the Andes (located in Deep Bay on the West Coast of Antigua). We stopped here for lunch on our final day of travel around Antigua. The waters were not super clear and made it hard to see at first, but if we dove down a few feet you could see the coral and algae growing on the boards across the hull, the mast sticking out and when the sun shown a little brighter, we could see little Sergeant Majors swimming around the bow of the boat, well lit and closer to the surface.

In summary, we had ourselves a grand old time and we’re very grateful to our hosts for such a wonderful and relaxing vacation. Thank you Mom and Dad (or Mike and Gloria)!

Signing off,

Sharp Eye (Tasha) and Toot (Mac)

Toot and Sharp Eye

Blog writing is a serious business!

Late afternoon, Great Bird Island

Last light, off Great Bird Island anchorage

We picked our anchoring spot in Jolly Harbor to have an unrestricted view of the sunset over the water for Tasha and Mac's final evening

The sunset didn't let us down ... it just kept going

Amazing light at the end of the day. The visibility today was incredible, we could see Nevis, St Kitts, Montserrat and Guadeloupe all at the same time

As the sun went down, the full moon came up ... just an astonishingly beautiful evening

Hanging out in Paradise

Hanging out in Paradise

Saturday 23rd - Monday 25th December

Happy Christmas! We are having a wonderful time anchored off Great Bird Island on the north coast of Antigua. Weather systems far to the north of us are depressing the trade winds in the Caribbean and it is unusually calm here. It’s a beautiful area, with flat seas and clear blue green water.

We sat in the cockpit yesterday and talked with Mac about holiday traditions, and came to the realization that we (the Block Breault family) really don’t have much in the way of Christmas traditions. Over the years we have celebrated the holidays in so many different locations that every year seems quite different. In the past, Gloria and I visited one or other of our respective parents (in the UK or the USA). Then in a break with that pattern, we went to Australia camping in 1990-1. In the years that followed, after Tasha was born, we sometimes got together with family and sometimes it was just the the three of us. We had an amazing time camping in Big Bend National Park when Tasha was about 5 years old, and spent several Christmas holidays in Florida. When we moved back to the USA our parents did occasionally come and stay with us, and we also travelled to the UK for the holidays. In the past decade we’ve been on the boat four times for Christmas, a couple of times with Tasha visiting and twice meeting up with family in Florida. Two years ago we joined Tasha and Mac in Baja Mexico, then last year we celebrated quietly at home. It’s been all over the place!

One of the aspects that we have loved about cruising is meeting other people. In Jolly Harbor we bumped into a couple called Irina and Tim and got chatting. Their daughter and her boyfriend are visiting them on their boat and by coincidence we all ended up in the same anchorage here off Great Bird Island. Last night we all got together and had some drinks and snacks aboard Cotinga. It was really fun. This is an aspect of cruising that was completely missing during the 2020-1 Covid years.

Today we hope to dinghy around some of the uninhabited islands, do a little snorkeling and have a pretty lazy day. If all goes to plan we are having ham, red cabbage and sautéed sweet potatoes for dinner, followed by damson plum crumble! It may not be traditional, but it’s what we have got!

Mike

17 08.706 N, 61 43.793 W

The view north from the top of Great Bird Island

The south beach, where we landed in the dinghy, Great Bird Island.

There were thousands of these small yellow butterflies

We believe these are the same type of butterfly that escorted us on our sail from the Virgin Islands to St Martins

I had a lot of fun photographing a pair of spiders, that were capturing the butterflies for dinner

We have two solar lanterns on board which are great in the cockpit. This image was created using focus stacking techniques and then inverted (to the negative) at the press of a button!

Nelson’s Dockyard and Ricketts Harbor

Nelson’s Dockyard and Ricketts Harbor

Thursday 21- Saturday 23 December 2023

There was almost no wind this morning when we got up.  The day was promising to be very warm indeed.  We ate a quick breakfast and set off to shore.  We arrived at the gate to the dockyard at 8:45 am, fifteen minutes early for opening time.  The chap on the gate let us go in with a promise to return and pay on our way out.  We had a walk around the area looking at the restored and preserved buildings.  Then a walk along the dock allowed us to look at the massive boats.  It was great to see the preserved buildings of this historic site, where soon-to-be Admiral Lord Nelson was stationed, alongside the modern functioning Marina. We were back on board by 11:00 am and making preparations to get underway.  

Once outside of Falmouth Harbor, we found that there was some wind—but right on the bow!  We motored east and encountered the large, long period swell that has been featuring so prominently in recent weather forecasts. By some amazing helmsmanship, Mike was able to bring us safely into Ricketts harbor at Green Island despite some swell breaking on the bar at the entrance.  Ricketts Harbor is a gorgeous spot and for today we have it all to ourselves (except for the numerous turtles!) 

Gloria

We were glad we took a somewhat approach to Ricketts harbor, putting the swell on our stern as we passed over the bar. The chart states quite clearly that the area can be dangerous when large swells are breaking. It was somewhat un-nerving to look out from our anchorage, which was perfectly flat, and see some of the larger swells breaking on the horizon. As Gloria mentioned, the anchorage was beautiful. We snorkeled the nearby reef (directly from Cotinga) and saw some coral and quite a lot of fish. In general, we have been quite shocked at the state of most of the reefs we have snorkeled. It’s hard to know how much is local damage and how much is due to global climate change. 

On Friday we jumped in the dinghy and motored round to Nonsuch Bay. We snorkeled three different sites, the best being the inner edge of the reef that fringes the Bay. Here the water was the clearest, but again the coral is in such poor shape. When we returned to Cotinga mid-afternoon we found four or five other boats in the anchorage. They weren’t noisy or intrusive, but it helped us realize how lucky we were to have one night completely to ourselves.

The following morning (Saturday), Gloria and I got up at 5.30 am, and after some coffee and final preparation, we hauled up the anchor and left Ricketts harbor by the same route we came in on. The large swells had settled down quite a bit and we motor-sailed northwards, continuing around the east coast. Our plan was to complete a circuit of Antigua and head back up the Boon channel to visit Great Bird island. This was the location we had failed to get to on our previous excursion up the bay, when the winds were so strong. Ironically, we passed the ocean side of Great Bird Island within an hour of our departure, but there is no safe way through the reefs and so we needed to continue around for another ten miles before heading back on the inside. Amazingly, Tasha and Mac managed to sleep through the first four hours of the passage and only emerged once we had made our turn back into the Boon channel! We were able to navigate safely across the final mile or two, where there are numerous shallow reef sections, and arrived at the anchorage around 11.30 am. It was a good plan! We spent the afternoon snorkeling some of the reef areas near the anchorage. It’s a beautiful place to stay.

Mike

17 08.716 N, 61 43.802 W

I took this shot of one of the workmen up near Shirley Heights yesterday. I had been struck by the colorful T-shirt, but when I worked up the photo I thought his expression and eyes were the most compelling aspect of the shot and the T-shirt was a distraction. Consequently, I decided to show the final image as a sepia tone B&W.

One of the more modern buildings at Nelson's Dockyard

A view of cliffs on the east side of Antigua, just to the north of Shirley Heights.

An early departure from Ricketts Harbor gave some of us a fine view of the sunrise!

We did end up motor-sailing with both Genoa and main, but there was never enough wind just to sail.

Beautiful conditions off the Atlantic coast of Antigua ... but very little wind.

Shirley Heights Revisited

Shirley Heights Revisited

Wed December 20^th, 2023

After breakfast, we dropped the engine on the dinghy, collected our kit and caboodle and motored to the dinghy dock in Falmouth harbor.  A quick consult with Google maps put us on the route to Shirley Heights.  It was already 11 am, so we had missed the coolest part of the day.  There were occasional patches of shade that were very welcome.  After what seemed like a significantly long uphill slog, we arrived at the pay station for the National Park (includes Nelson’s dockyard, Shirley Heights and the interpretive center at Dow Hill).  We elected to walk up to Dow Hill to watch a video about the history of Antigua.  The film was shown in a blessedly cool room.  We learned that the island had been named by the Spanish but became an English possession.  The secure harbor was the great attraction for the British Navy.

We walked down from Dow Hill to rejoin the main road.  From there, we walked up hill to the “Blockhouse”—naturally we had to visit this site!  Much to our delight we found a woman with a little stall selling many items including cold drinks.  We drank our cold beverages while taking in the views down to the ocean.  Retracing our steps we rejoined the road to Shirley Heights.  It was back to walking up hill now completely in the sun.  Finally, we arrived at our destination.  I was astonished to read a sign that reported that these Heights were 490 feet above sea level.  My feet and legs did not agree.  

A snack lunch was consumed on the terrace, where pic-nicking was prohibited! One member of our party even stepped past the sign saying “Dangerous cliff! Do no go beyond this point!”  Perhaps we have a hard time following the rules.... After our lunch we set out of the half-mile path that descends steeply to Galleon beach below.  To our dismay, Google maps was now telling us that we had to walk back up hill to join the main road and then retrace our earlier route.  More trudging up hill was just what I felt like doing.  

We were quite sweaty and disheveled by the time we returned to the dinghy dock. A round of cold drinks followed by showers did much to restore our spirits! We formulated plans for the following day while having dinner.  In the morning we would take a quick trip around Nelson’s Dockyard and then set sail for Green Island.

Gloria

Whilst it was hot and sunny where we were, you could see squalls passing in front of the island of Montserrat. Photo taken from Shirley heights

Remnants of a more modern wall at the top of the cliff at the Blockhouse

The view towards Montserrat to the west

Mac

Tasha cooling off at Shirley Heights after our hot hike up the hill

A fine rooster we passed on the way home

Tasha and Mac Arrive

Tasha and Mac Arrive

Sat 16th - Tues 20th Dec

On Saturday morning we pulled up the anchor, headed out to sea to empty our holding tank, and then back into the marina at Jolly Harbor. We were assigned a stern in “Mediterrainen” style slip, which isn’t always the easiest for us to get into, but unlike any other marina we have ever visited, the dock master and his assistant were there to help us in a dinghy. The slips are double-wide to accommodate catamarans and so with two mono-hulls in occupancy we needed lines to the corner posts and also to our neighbor. The dock master sorted all of this, along with giving us a push at the side of our hull with his dinghy to help us line up. Outstanding service! In the evening we had dinner out at a local curry house, which was excellent.

Tasha and Mac had a grueling flight schedule … Spokane to San Francisco to Newark to Antigua … almost 24 hours. They were delayed out of Spokane and nearly missed their connection, but all turned out well and they arrived by taxi at the marina on Sunday afternoon. It was terrific to see them. We booked to stay on the dock for Monday night as well, to make settling in a little easier, and so we had a fairly lazy time wandering down to Jolly Beach for sunset on Sunday and then taking the dinghy back to the beach at Pearns point on Monday.

Unfortunately, on Saturday night after dinner (unrelated) I started to feel ill. The symptoms are vague, but I’ve certainly been running a fever and barely have the energy to do anything. This was not the welcome I hoped for Tasha and Mac. Fortunately, I have gradually been starting to feel better.

On Tuesday morning we left Jolly harbor and sailed down to Carlisle Bay on the south coast, and dropped anchor. After a leisurely lunch and a swim in the crystal clear blue water, we continued eastwards and into Falmouth harbor, where we hope to spend a couple of days exploring.

Mike

17 01.010 N, 61 46.418 W

Tasha and Mac in Carlisle Bay

Gloria about to swim in the clear blue waters of Carlisle Bay

Sunrise in Falmouth Harbor