The Stornoway slipway is a big commercial railway that can lift boats up to 50m long and weighing up to 850 tons. The railway cradle uses three pairs of hydraulic support arms to hold boats in place, making for an efficient lift process. Once the vessel is in the correct position, the arms are simply raised into place rather than having to position supports and blocks by hand as the boat comes out of the water.
After refuelling, reprovisioning, refinishing our teak furniture, completing the wax job, and replacing the cylinder head on our generator, our final Stornoway project was a haul-out for bottom paint and an insurance survey. We initially had planned to do this later in the year while we were in the Mediterranean, but that wasn’t going to happen. The Stornoway slipway had recently re-opened after the lockdown and was able to fit us in. The yard is very commercial boat focused, but everyone was super-helpful, careful, and professional, and the job went extremely well even though our boat is a bit unusual for this facility.
This is the second time Dirona has been hauled out on a railway instead of the more common travel lift. Our first was in Whangarei, NZ.
Below are highlights from July 6th through 11th, 2020. Click any image for a larger view, or click the position to view the location on a map. And a live map of our current route and most recent log entries always is available at mvdirona.com/maps.
7/6/2020
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Slipway Dock
Position: 58°12.21’N, -6°23.08’W
Dirona moored at the Stornoway Port Authority slipway dock, ready for our haul-out.
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Stornoway Slipway
Position: 58°12.21’N, -6°23.08’W
View to the Stornoway slipway prior to our haul-out. The whole assembly will slide down the rail and into the water, including the boat at the top of the railway and the control tower behind.
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Hydraulic Support Arms
Position: 58°12.21’N, -6°23.08’W
One of the three pairs of hydraulic support arms to hold boats in place on the railway cradle. In order to support large and heavy commercial vessels, the hydraulic rams are quite powerful and could damage our relatively delicate 50-ton boat or do major damage to the stabilizers or keel coolers if they made contact. So the crew needs to use care when lifting the arms. The slipway manager requested pictures and diagrams of the hull, so they know exactly where to place the supports. The crew work efficiently and patiently, and every arm ends up exactly where it needs to be for a nice gentle lift.
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Ready To Go
Position: 58°12.22’N, -6°23.08’W
Precisely at our haul-out time of 9am, the Stornoway slipway crew had us ready to go and the cradle started sliding down the railway.
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Coming Out
Position: 58°12.21’N, -6°23.05’W
Dirona just coming out of the water, secured with a bow-line forward, as the cradle moves back up the railway. The white squares visible through the water are the ends of the hydraulic support arms.
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Arms in Place
Position: 58°12.20’N, -6°23.04’W
Dirona coming out of the water, resting on one pair of hydraulic arms. The slipway crew did an awesome job of perfectly and carefully positioning the supports.
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Out of Water
Position: 58°12.20’N, -6°23.03’W
Fully out of the water, with both hydraulic lift arms visible. It’s only been 20 minutes since we started the haul-out.
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On the Hard
Position: 58°12.18’N, -6°23.00’W
Dirona on the hard at the Stornoway slipway, our new home for the next little while for an insurance survey and bottom paint. We’ll post a video of the full haul-out.
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Power Wash
Position: 58°12.18’N, -6°23.00’W
The hull being power-washed within minutes of Dirona being completely hauled out. The slipway crew was super-efficient and always careful—we’re quite impressed.
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Extra Support
Position: 58°12.18’N, -6°23.00’W
To ensure Dirona doesn’t slide off the cradle, the slipway crew put two additional support arms in place.
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Props
Position: 58°12.18’N, -6°23.00’W
A view to the running gear shortly after the haul-out. We have a bit of barnacle growth, but not much marine growth yet on the paint given we’ve not cleaned the bottom since it was painted 2.5 years ago. We were starting to see some growth at the waterline and our experience has been that once that starts, it gets worse fast.
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Stabilizer Fin
Position: 58°12.18’N, -6°23.00’W
It looks like the starboard stabilizer fin just barely touched bottom. We didn’t know about this event, but it might have been in some of the tight passages in Finland’s Great Saimaa Lakes region.
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Hull Wear
Position: 58°12.18’N, -6°23.00’W
Here it looks like the boat was up against an underwater obstruction or projection from a dock, and the paint wore off in this location as the boat gently moved up and down in the water.
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Flaking Paint
Position: 58°12.18’N, -6°23.00’W
In general the bottom paint looked remarkably good for 2.5 years. There were a few locations where the paint appeared to be flaking away. Two of them were in the area that was underneath the travel lift strap. We suspect these just weren’t sanded properly prior to painting. Another couple of spots down near the props were either caused by turbulence from the prop or, more likely, inadequate sanding in that one area. Generally, 2.5 years later, it looks like the last bottom paint was executed fairly well with good adhesion over most of the hull bottom and it has stood up to 2.5 years of use very well. Partly good workmanship, and partly excellent paint in International Micron 77. Unfortunately Micron 77 is too effective to pass current EU pollution standards, so we’ll be applying Micron 99 this time.
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Generator Delivery
Position: 58°12.18’N, -6°23.00’W
This is a first for us, but this big commercial yard doesn’t have 240V utility power and instead runs their equipment off a big generator that operates during the day. We can’t run our generator while we’re out of the water, so with no shore power available we rented a 6kW diesel generator for the time we are here. The Stornoway Port Authority, who operate the slipway, has been exceptionally helpful. They picked up the generator for us and here they are dropping it off, exactly where we want it.
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Shore Power
Position: 58°12.18’N, -6°23.00’W
Dirona plugged into shore-power via a diesel generator. It’s a simple trick that works remarkably well.
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4.2 Degrees
Position: 58°12.18’N, -6°23.00’W
Resting at 4.2 degrees on the slipway is a little like being at sea. 4.2 degrees is close to nothing, but when constant feels surprisingly large. Round items will roll of the counter, we’re using heavy-duty latches to keep the freezer drawers and pantry from sliding open, and we secure large pots of water on the boil with pot holders. And we have to be careful going down the stairs into the salon as they are at a steeper angle than usual. On the plus side, the lazarette floor that slopes down forward is now level. :)
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Y-Valve
Position: 58°12.18’N, -6°23.00’W
Our galley drain has a Y-valve to direct outflow either overboard or into the grey water tank. Here we’re about to switch the Y-valve to direct the galley sink water into the grey water tank rather than overboard. We do this while in the yard or at locations where even grey water must be kept on board.
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Sarnia Cherie
Position: 58°12.18’N, -6°23.00’W
We love the view from our perch in the yard, particularly of all ship arrivals and departures. Here the oil tanker Sarnia Cherie is arriving into Stornoway for a bi-weekly fuel delivery.
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Removing Zincs
Position: 58°12.18’N, -6°23.00’W
James removing the zincs from the running gear while the painters clean the keel cooler.
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Keel Cooler Zinc
Position: 58°12.18’N, -6°23.00’W
There wasn’t much left of the keel cooler zincs.
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Old Zincs
Position: 58°12.18’N, -6°23.00’W
The remains of our zincs. The zincs definitely needed replacing, but are in remarkably good shape after 2.5 years.
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New Zincs
Position: 58°12.18’N, -6°23.00’W
A new set of zincs ready to go on after the bottom paint.
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Detaching PSS
Position: 58°12.18’N, -6°23.00’W
Now that the boat is out of the water, we can inspect the PSS (packless shaft seal) installation. We had PSS on our previous boat for 10 years and it never leaked, and have had excellent service on this boat for 8 years. In the last yard service, the prop shaft was replaced and unfortunately the new shaft is out of true. Its runout is only around 0.008″ but it’s enough to vibrate slightly and this causes the PSS to leak. As you can see in picture this slight leak is making a real rusty mess of the area around the PSS.
The best possible solution is to replace the shaft, flange, and PSS seal assembly but, the more we think about this, the more we wonder why it leaks with only a relatively small amount of shaft runout. The shaft runout is more than it should be, but normally PSS seals are fairly forgiving. We decided to take it apart to see if it was installed correctly when the shaft work was done. We found that the carbon stator was resting against the shaft at the top where, if properly installed, the shaft should be central in the bellows and rotor. The rotor should “float” and be only minimally affected by the shaft runout. But, in this install, the rotor was forced against the shaft at the top and, with the shaft runout, will be vibrated badly. This certainly will cause a leak. It may still leak with this corrected due to excess shaft runout, but we suspect that this will substantially reduce the leak and perhaps fix it. |
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PSS Detached
Position: 58°12.18’N, -6°23.00’W
The PSS completely detached. The reason this job has to be done out of the water is the gap between the shaft and the shaft log is open to the sea and this will bring in a large amount of water in a very short time.
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PSS Reinstalled
Position: 58°12.18’N, -6°23.00’W
The PSS reinstalled properly and the bilge area cleaned up. We managed to reinstall the PSS so that it properly “floated” around the prop shaft and is equally compressed all around. We also compressed the bellows to the manufacturer’s specification, which is considerably tighter than it was after the last installation. Between properly aligning the rotor and bellows to the shaft and compressing the bellows to correct specification, we think there’s a good chance that we’ve eliminated this leak, or at least reduced it dramatically.
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Loch Seaforth
Position: 58°12.18’N, -6°23.00’W
The ferry Loch Seaforth arriving into Stornoway from Ullapool on the Scottish mainland. The paddle-shaped symbol at the waterline directly below the first ‘n’ in Caledonian indicates the active stabilizer location so tug boats can stay clear. Stabilizers aren’t that common on a ferry of this size, but this one operates in difficult weather conditions and likely needs it.
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Supports
Position: 58°12.18’N, -6°23.00’W
Looking along our starboard side to two of the four substantial hydraulic support arms holding Dirona in place.
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Stern View
Position: 58°12.18’N, -6°23.00’W
The view west from our stern down the railway and across the ferry dock to central Stornoway.
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7/7/2020
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Generator
Position: 58°12.18’N, -6°23.00’W
Our shore power generator is working out great. We run it 24×7 and it feels just like we’re plugged into shore.
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Loch Seaforth
Position: 58°12.18’N, -6°23.00’W
The ferry Loch Seaforth turning in its own length to depart Stornoway this morning at 7am. The ship arrives and departs three times daily, with the first arrival around 5:30am and the final departure around 8:30pm. We enjoy the ship traffic visible from our slipway perch, particularly the ferry, and generally stop whatever we’re doing to watch the Loch Seaforth come and go.
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Lews Castle
Position: 58°12.18’N, -6°23.00’W
View from the Stornoway slipway to Lews Castle, built in the mid-19th century.
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Spitfire
Position: 58°12.18’N, -6°23.00’W
Spitfire doesn’t like other boats too close and has become quite concerned about the pilot boat Portrona ahead of us on the slipway.
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Sanded
Position: 58°12.18’N, -6°22.98’W
At the end of the second day of our haul-out, the boat has been masked around the paint line, completely sanded and washed, and is ready for painting tomorrow. We’re making excellent progress.
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Fin
Position: 58°12.18’N, -6°22.98’W
The starboard fin area after sanding.
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Welded Plate
Position: 58°12.15’N, -6°22.97’W
The pilot boat Petrona, ahead of us on the slipway cradle, has a few sections in its hull that have become too thin over the years. Steel hull plates are being replaced in several places on the ship. Before we could haul out, the crew had to finish plating up the stern of Petrona since picking us up on the same rail carriage would require that boat being partially in the water.
Today the crew heated and bent a plate for the bow. They’re also replacing a steel plate at the a fuel tank, which means they have to pump the fuel out and clean it sufficiently well to not be a fire hazard before welding. They work remarkably quickly. |
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Wild About Shellfish
Position: 58°12.16’N, -6°22.86’W
On a walk around Goat Island, where the Stornoway slipway is located, we walked past an office of Scottish-based shellfish company Macduff and loved their motto. According to their web site “We process more wild shellfish than anyone else in Europe – and that’s all we do. We are masters of our trade.”
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Cromwellian Fort
Position: 58°12.17’N, -6°22.74’W
Plaque commemorating a 1653 fort built by Oliver Cromwell’s forces when they occupied Stornoway during a pro-Royalist uprising in the northwest Highlands.
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Seawall
Position: 58°12.20’N, -6°22.57’W
The substantial seawall protecting the road to Goat Island, with the edge of the Stornoway slipway yard visible in the background on the right. Despite the width and height of the wall, we found sizable piles of seaweed that waves had carried over to the other side of the road.
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Dirona
Position: 58°12.24’N, -6°22.53’W
Dirona prominent on the Stornoway slipway behind the pilot boat Portrona.
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H M Coastguard
Position: 58°12.20’N, -6°22.61’W
H M Coastguard office at Stornoway. We hear them on the radio all over the Hebrides.
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New Marina
Position: 58°12.19’N, -6°22.80’W
A view to Stornoway’s new 75-slip marina, scheduled to open this year. The inner harbour where Dirona was moored is often full in the summer, so this will open up much-needed space to increase visiting recreational boat traffic.
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TravelLift
Position: 58°12.23’N, -6°22.97’W
The new marina development at Stornoway includes plans for a 100-ton TravelLift to be operational at the end of this year.
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Bow View
Position: 58°12.18’N, -6°22.99’W
Looking down the slipway to Dirona resting on the four hydraulic support arms in the Stornoway slipway cradle. It certainly is an unusual sight.
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Ladder
Position: 58°12.19’N, -6°23.02’W
With the added height of the cradle and railway, a reasonably long ladder is needed to reach the swim step from the ground.
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Railway View
Position: 58°12.19’N, -6°23.00’W
Looking up the slipway to Dirona sitting on the cradle. As with any haul-out, we can’t help but be a bit nervous, just because these operations carry more risk than a normal day boating. Rail lifts can be safer, and better for the boat, than travel lifts and shore-side blocking. But the job requires more skill, and if not done well, can be a big problem.
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Mail
Position: 58°12.18’N, -6°23.00’W
Since we wouldn’t be returning to Seattle this summer, we had our surface mail forwarded from our UPS box to Stornoway and it arrived today. We had surprisingly little given that we last got our mail in early February.
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7/8/2020
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Paint Pickup
Position: 58°12.18’N, -6°23.00’W
The paint crew using a forklift to pickup our paint from the swim platform. The forklift is a good choice, since the pails weigh over 50 lb (23 kg) each.
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Props Covered
Position: 58°12.18’N, -6°23.00’W
The propellers covered in preparation for the bottom paint.
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First Coat
Position: 58°12.18’N, -6°23.00’W
Macmillan Engineering applying the first coat of bottom paint.
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Freezer Hot
Position: 58°12.18’N, -6°23.00’W
We had a bit of a scare this morning when we noticed the freezer temperature was at 24F (-4.4C), barely below freezing, and a couple of items in the top drawer had thawed completely. The freezer is packed full and we were worried we were going to lose the entire load. And worse, if the freezer was broken, we’d be in real trouble. SubZero no longer makes that model and getting replacement parts from the US, even if we could fix it, would take time.
It struck us as odd, however, that everything was still frozen except for two items at top center in the upper drawer. And those shouldn’t have thawed anyway because the freezer temperature still was technically below freezing. We discovered that even though we had secured the drawers with latches, the top drawer had opened slightly due to the boat being on a 4.2° incline sitting on the slipway. This was enough to turn on the light at top center of the upper freezer drawer. The bulb was too hot to touch and the heat from it had thawed the items directly below it and warmed up the freezer. We wedged the drawers tightly closed with cardboard, the light stayed off, and the temperature fell back to 0F (-18C) in minutes. Whew! |
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Second Coat
Position: 58°12.18’N, -6°23.00’W
The paint company, Macmillan Engineering, took advantage of today’s excellent weather and at times had as many as four people on the boat to ensure we got two coats of paint on today. The job is progressing super-well.
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Paint Line
Position: 58°12.18’N, -6°23.00’W
The Macmillan Engineering painters are so careful in painting the bottom that they’re barely touching the masking tape.
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Stern Tube
Position: 58°12.18’N, -6°23.00’W
Painting the inside of the stern tube.
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Shower Pan
Position: 58°12.18’N, -6°23.00’W
The shower pan is on a slight angle forward, and water normally collects at that end. But on a 4.2° aft incline, the water is all collecting at the aft side of the pan. It’s hard to see in the picture, but there’s no water at the front and it’s more than an inch deep at the back.
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Climbing Down
Position: 58°12.18’N, -6°23.00’W
Climbing down for an inspection of the day’s work and a short walk around Goat Island.
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HebDrone
Position: 58°12.17’N, -6°22.86’W
HebDrone was out testing their subsea ROV (Remotely Operated Vehicle) for a job tomorrow. The one they were testing is rated to depths of 300m.
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Dirona
Position: 58°12.18’N, -6°23.00’W
Dirona in the Stornoway slipway cradle with two coats of bottom paint.
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Crushing
Position: 58°12.18’N, -6°23.00’W
Dirona is supported by five relatively evenly-spaced blocks of wood. But even with that weight distribution, 55 tons leaves its mark.
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Tide Pools
Position: 58°12.18’N, -6°23.00’W
Jennifer jumping among the tide pools at low tide. Given the location right below a shipyard, the pools were full of life and healthy pink corraline algae.
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Arnish Point Lighthouse
Position: 58°12.18’N, -6°23.00’W
View on a calm evening from the Stornoway slipway yard to the Arnish Point Lighthouse at the entrance to Stornoway.
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Refueling
Position: 58°12.18’N, -6°23.00’W
James refueling our shore-power generator. We generally need to fuel it twice a day, which works out well for us.
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7/9/2020
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Loch Seaforth
Position: 58°12.18’N, -6°23.00’W
The ferry Loch Seaforth arriving at 5:20am for the first run of the day at 7am. The ship’s first scheduled morning departure and last evening arrival are both at Stornoway, but the ship doesn’t overnight here.
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Equipment
Position: 58°12.18’N, -6°23.00’W
We’ve been quite impressed with how clean and tidy the Stornoway slipway yard is, and how well the crew maintains their equipment. This Magni telescopic handler is in excellent condition with hardly a scratch or dent, but the Stornoway Port Authority took delivery four years ago in 2016.
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Fender Door Stop
Position: 58°12.18’N, -6°23.00’W
We slid our patio table into the forward port corner of the cockpit to keep it out of the way and reduce the likelihood of damage to the fresh paint. But with the boat at a 4.2° angle, the salon door will swing hard into it if we aren’t careful. We solved this by using one of our fenders as a doorstop.
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Painting Under Support
Position: 58°12.18’N, -6°23.00’W
The slipway crew lowered the two forward hydraulic support arms so the painters could reach there.
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Paint Used
Position: 58°12.18’N, -6°23.00’W
You can tell how good a job the Macmillan Engineering paint crew did by how much paint is left. In between showers today, the painters applied a third and final full coat on the entire hull and used up all of one and about 2/3 of the other 20L pails of Micron 99.
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Wing Prop Shaft
Position: 58°12.18’N, -6°23.00’W
Cleaning off the wing prop shaft in preparation for installing the new zincs now that the bottom painting is complete. This will ensure the zinc is electrically well-bonded and tight on the shaft.
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Main Prop Zinc
Position: 58°12.18’N, -6°23.00’W
Installing the main propeller zinc. The main propeller shaft itself doesn’t have any zincs due to insufficient clearance.
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Retaining Cross
Position: 58°12.18’N, -6°22.99’W
The main prop zinc is held in place with a bolt that is further secured using a retaining cross with one arm bent over. In addition, two set screws hold the zinc in place at the base. This is all to prevent the bolt from backing out due to propeller rotation.
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Wing Prop Zinc
Position: 58°12.18’N, -6°23.00’W
The wing prop zinc was slightly too large to allow the propeller to fold properly, so we sanded it down.
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Wing Shaft Zincs
Position: 58°12.18’N, -6°23.00’W
Installing the three wing propeller shaft zincs. Here James has tightend them all down. He then taps each half once with a hammer and then tightens them again to ensure they are set and electrically well connected.
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Line Cutter Zincs
Position: 58°12.18’N, -6°23.00’W
The two new Spurs line cutter zincs in place.
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Hull Zincs
Position: 58°12.18’N, -6°23.00’W
One of the four new hull zincs in place. Besides the one on the transom, we have one on the the rudder foot and one on each side of the hull. Here James is installing the final one on the starboard side.
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Keel Cooler Zinc
Position: 58°12.18’N, -6°23.00’W
One of the two new main engine keel cooler zincs in place. The hydraulics keel cooler on the starboard side doesn’t have zincs because it’s made of titanium.
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Thru-Hull Covers
Position: 58°12.18’N, -6°23.00’W
The thru-hull covers re-secured with cotter pins.
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Masking Tape
Position: 58°12.18’N, -6°23.00’W
As the masking tape comes off, you can see how careful a job the Macmillan Engineering paint crew did near the edges.
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Refueling Gen
Position: 58°12.18’N, -6°23.00’W
Our twice-daily refueling of the shore-side generator providing us power. It’s worked out super-well.
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BRMC
Position: 58°12.18’N, -6°23.00’W
In 2017 we took in one of favorite bands, Black Rebel Motorcycle Club, live at the Limelight in Belfast, Northern Ireland. Tonight we watched them on YouTube put on another great show at the 2018 Down the Rabbit Hole music festival in the Netherlands.
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7/10/2020
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Rear Support Arm
Position: 58°12.18’N, -6°23.00’W
The rear hydraulic support arm down slightly for the painters to reach underneath.
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Control Tower
Position: 58°12.18’N, -6°23.00’W
We got an opportunity to check out the slipway control tower shortly before our launch this morning.
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Slipway View
Position: 58°12.18’N, -6°23.00’W
The view from the control tower with the pilot boat Portrona ahead of us on the slipway.
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Launching
Position: 58°12.19’N, -6°23.03’W
We’re launching this morning after a speed record of only four nights in the yard. This is by far our shortest biennial yard trip ever.
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All In
Position: 58°12.21’N, -6°23.06’W
As with the haul-out, the slipway control tower and the pilot boat Portrona ahead of us all descend together down the slipway.
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Floating
Position: 58°12.21’N, -6°23.07’W
Everyone is paying close attention as the hydraulic support arms fold away and Dirona floats free.
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Tesco
Position: 58°12.42’N, -6°22.98’W
The lockdown restrictions in Scotland eased a bit while we were in the yard, and more people are on the streets to visit the newly-reopened shops. But unlike last week, those that are out mostly are wearing face masks and the Tesco grocery store is now requiring them.
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Provisions
Position: 58°12.56’N, -6°23.41’W
Returning to Dirona with our eight cartful of provisions to replenish the stores we’d used in in the past month.
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Scrubbing Deck
Position: 58°12.56’N, -6°23.41’W
The Stornoway slipway is quite clean by commercial yard standards, but it still is a boatyard and avoiding getting dirt all over the boat is difficult. Here we are scrubbing off the non-skid.
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Waxing
Position: 58°12.56’N, -6°23.42’W
Some of the dust from sanding the bottom settled on the boat and lightly stained the gelcoat on the horizontal surfaces. Fortunately it was relatively easy to remove with a quick waxing pass.
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Happy Hour
Position: 58°12.56’N, -6°23.42’W
Happy hour on the back deck after a busy day of launching, shopping, scrubbing and waxing. The yard visit was a real success and we’re enjoying being back at the Stornoway inner harbour for a couple of nights.
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7/11/2020
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Hopeful Seals
Position: 58°12.56’N, -6°23.42’W
Hopeful seals waiting for a handout next to a newly-arrived fish boat. They seem to know the drill—whenever a new boat arrives, they are alongside immediately.
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Waxing Port Side
Position: 58°12.56’N, -6°23.43’W
A quick wax of the portside horizontal surfaces to remove the gelcoat stains from the yard.
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Click the travel log icon on the left to see these locations on a map, with the complete log of our cruise.
On the map page, clicking on a camera or text icon will display a picture and/or log entry for that location, and clicking on the smaller icons along the route will display latitude, longitude and other navigation data for that location. And a live map of our current route and most recent log entries always is available at mvdirona.com/maps. |
Dear James,
its very interesting to read your articles! Thank you for all the effort you are investing.
We were in Stornoway close to your boat, the catamaran Anna Bamboo, Peter and Antje. Reading the details of the PSS, I am thinking of our shaft seal which is working a bit like the PSS, but with an essential difference: the sealing rotor/stator is in contact with the water from “outside”. This centrifuges abrasive particles away from the sealing, which allows a very long lifetime. Also the complete item is rigid bronze from outside, no rubber tubes, no clamps etc. In addition they offer an inflatable stand-still shaft seal from shaft diameters 50mm and above which allows to do possible adjustments with the boat in the water (or in case the thing should collapse.
We have these seals on our 2 drives and are very pleased. Please have a look on http://www.profiseal.de and please excuse my poor english, as this is not my mother language. BTW we are still in Stornoway!
Good hearing from you again. We hope all is well in Stornoway. One of our favorite spots.
Thanks for posting the reference to the lip seal system. I generally like the lip seal systems I’ve looked at and this one looks more innovative than most.
We’ve used PSS seals successfully for 21 years and up until this issue, we’ve been very happy with them. What we have learned here is the PSS system is less able to adapt to shaft runout than lip seal systems. However, if the shaft work had been done correctly, we wouldn’t have excess runout and any form of shaft seal would work perfectly well. We’re we to do it again, we would spec a lips seal system just because we like systems that have more engineering margin.
Dear James,
the Profi Seal system is not a lip seal system. In fact it works like the PSS, utilizing a face to face seal, a carbon ring against a SS (stainless steel) face. The contact pressure comes from a SS spring with a dedicated load. The lip, you might have seen in the cross section of the Profi Seal, is only to seal the rotor against the shaft (same with the O-rings at the PSS).
The Profiseal allows +- 5mm movement in axial direction and +- 2mm in radial direction (something you would definitively NOT allow on your boat, I suppose :-) )
Thanks for the additional detail on Profiseal Peter.
You’re always a font of great tips. I’m a big PSS fan after life with with the leaky stuffing box on my old boat. Was your PSS rotor resting against the shaft because the bellows wasn’t aligned properly on the stern tube? If I’m following manufacturer guidance (my seal is 8 years old), I should replace my bellows so it would be great to know what to watch out for in the reinstall.
Sorry for the confusion. I just read your explanation again. I was imagining the carbon stator wasn’t centered around shaft, but actually I think you’re saying the stainless rotor was vibrating excessively due to its placement? I’m probably still confused…
Hey Tim. Good hearing from you. Our bellows was misaligned which causes the carbon stator to be up against the shaft. The PSS design is pretty tolerant of alignment issues so, even if misaligned, the bellows should absorb it and the carbon stator should just find the right spot but, on ours, it was adjusted with only light pressure. The combination of large misalignment and the bellows being insufficiently tight, let to contact between the shaft and the inside of the stator. Even this might have been tolerable but the shaft alignment is just outside of spec. The combination of aligning the bellows and tightening them correctly just about stopped the leak. The PSS spec gives the bellows adjustment and says “tighten 1/4″ more if leaking” and I think if we did that, there would be no leakage even with our shaft alignment issue. But, because the stainless rotor was set so loose, the set screws have marked the shaft where the O-ring would ride and I don’t have the courage to tighten it another 1/4″ since this would force the O-ring over the sharp set-screw mark on the shaft. At this point, it is very close to dry so we’ll leave it as it is.
In using PSS for 21 years, this is the only issue we have had and all the problems relate to installation problems and just don’t need to happen. So, the above sounds like a mess and it is a bit of a mess, but it’s mostly caused by installation mistakes rather than the PSS issues. However, many folks I know that have used both Tides and PSS, believe the Tides seals require less attention/adjustment and some of these folks have switched to Tides seals.
Got it. Thanks again for the pointers.
interesting to see dirona hauled out may I ask the art work on each side of the bow of dirona is it your design or did it come with dirona
The artwork on each bow is the work of Margaux Marine Graphics (http://margauxmarinegraphics.com/). The artwork is a depiction of Dirona Albolineata, or the Alabaster Nudibranch, an invertebrate indigenous to the Puget Sound that we often see when scuba diving. Over 3,000 Nudibranch species live throughout the world’s oceans—their fantastic forms and psychedelic colors make them among our favorite sea creatures. That’s the origin of the name of the boat (https://mvdirona.com/dirona/).
thank you for the information it’s nice artwork
Mr. Hamilton:
Thank you for publishing such an interesting and detailed documentary of your haulout.
Forgive the “dumb” landlubber question, but what is the purpose of the stern tube, and why does the rudder have a large round hole in it?
Both good questions. The stern tube hoses the stern thruster. This is a pair of propellers that force water through the tube to push the stern of the boat to the left or the right for close quarters maneuvering. There is a similar tube and set of props in the front of the boat to move the bow left and right.
The hole in the rudder is there to permit easier service. This hole allows the prop shaft to be removed without first removing the rudder.