Wednesday, April 13, 2011

Day 2 of the Haulout

The hardstand electrical supply jury-rig

The battle with the cutlass bearing and improvised tools...

An old zinc plate
Marquesa in her new home

Well, Dave hopes to get done in a couple weeks. We shall see...
Today I learned a bit about drive train components. The cutlass bearing is the bearing that holds the shaft after it exits the hull. It's a bronze tube with a very hard carbon/rubber-type interior that contacts the shaft. It is pressed into a bronze housing that bolts to the hull. Slots in the housing let seawater in to keep things cool. Everything is pretty big and strong and redundant. The 'bronze' is silicon bronze, which is made of copper and tin, plus 1-3% silicon and 1 % either iron, nickel, or manganese. You wouldn't think something made of copper and tin would be a lot stronger than stainless steel, but it is. Most fittings on boats are made of it. Even the rigging up top that looks like stainless is usually silicon bronze with a shiny chrome coating. Dave actually missed getting all his original stainless steel rigging hardware replaced by superior silicon bronze for free when Taenna did a recall (he heard about it 2 months after it ended). Another benefit of silicon bronze is that it's a natural dielectric - electric flow called electrolysis has a potential to eat up metals on boats if they are placed next to a dissimilar metal - a dielectric metal doesn't provide a pathway for this electrical flow. More on electrolysis later when I understand it better. It's a phenomenon that constantly comes up in conversations at the boatyard. I notice with interest that everything in the cutlass bearing housing is bronze except for the studs which hold it on. They are stainless steel because they screw in to a stainless steel plate inside the boat (cheaper than bronze for the manufacturer) and, more importantly, because stainless is more corrosion resistant than bronze. The housing is held on redundantly by double nuts - the outer nuts have holes drilled through them for cotter pins. The bearing is pressed into the housing and also held in place by set screws.
Dave normally replaces his cutlass bearing whenever he has the drive train apart - every few years. It gets a lot of wear, and isn't too expensive, so it just makes sense. At home, he has a press to take out the bearing. Here in Whangarei, we end up heating the housing with some MAPP gas, and alternate hacking at the bearing's plastic and sticking a socket into the housing and banging on it violently. In typical beginner's fashion am starting to have visions of an elaborate pressing contraption involving an overhanging concrete wall, some boards, and a bottle jack, when finally what's left of the thing reluctantly slides out. Improvisation is fun.
I wet sanded the cuprous-oxide antifouling paint with 60 grit and stressed out about whether I was actually removing the green algae layer or just making it disappear behind a thin layer of liquified red paint. I'd be very anal if this was my boat, so I really try to be up to what I take to be Dave's standards. Though the hull looked clean from a distance, there was a lot of algal growth and embedded little shells to be removed, especially at the waterline, the bottom 2', and the rudder.
I finished sanding the hull while Dave did a blur of other things, including weirdly jury-rigging one of the batteries to power the boat (which had to be removed to take apart the propeller shaft) using a cable and a couple sets of locking pliers. I try to stay away from that general area now. He also cleaned all the drive components, took the prop to be polished and balanced, took the cutlass bearing housing over to be sandblasted, took the propeller shaft to multiple shops to be inspected as it had some major wear, ordered a damper...

Tuesday, April 12, 2011

Hauling Out In Whangarei

Setting up the hardstand.

Farewell, Whangarei Port Basin Marina. Your pretty sunrises will be missed, your scummy tidal river waters will not.
Hauling out at Dockland 5 in Whangarei. This is Dave's first time coming out on a travel lift, as his home port has ways.
Hauling out on a travel lift is sort of a scary-looking process. We motored in to the square cut-out under the lift and they positioned the straps in what seemed like a very casual way. We just fit, winding up with only inches to spare between the keel and the ground, and between the forestay and the frame of the travel lift. Though the lift looks small, it can lift a boat four times the weight of the Marquesa. The forward-looking radar transducer got tweaked a little by one of the straps, but otherwise everything went OK. When she arrived at her slot, they lowered her down on a couple transverse steel beams, shimmed underneath with three piles of scrap blocks, and pushed the 4 vertical steel supports that slid along the steel beams against her sides to keep her from tipping. Very haphazard looking! But stable, of course.
She's pretty clean underneath. Relatively little grows in the tropics- warm water tends to be oxygen- and nutrient- poor compared to rich cold fishing-ground waters like California, Maine, western South America... After being power-washed, she hardly even looked like she needed paint. Curious potential boat-buyers who are doing the rounds of the boatyard gravitate to the clearly well-maintained Marquesa and pelt Dave with questions daily.
As soon as she was out of the water we took a look at the prop, which had been vibrating. It had an inch or so of rotational play- not good. The moment she was set up on the hardstand Dave went to work taking apart the drive train to make sure the play wasn't coming from a damaged gear box. He rebuilt the engine and gear box just before leaving on this trip, so that would have been a real shame.
Dave used a home-made prop puller to remove the prop, and unbolted the collar, waterless packing, and cutlass bearing so he could remove the shaft. This is the first time I've seen a drive train taken apart, so I was a bit disappointed to be underneath the boat, sanding, while all this interesting stuff was going on! Fortunately the issue turned out to be due to a known problem- a worn key in the collar. That should be much easier to fix- we can cut a couple inches off the propeller shaft and fill the space with a damper, then re-key the shaft lower down.
The hauling out and power wash cost only about US $115. A hardstand at the yard costs $15/day and includes power, environmental fees, and cooking and hygiene facilities. As I soon discover, this is one of the very few things which is reasonably priced in New Zealand. Power here is 220V, and the boat's wired for 110V, so we'll be running off battery power while we're in the yard unless we can get ahold of one of the scarce transformers.

Monday, April 11, 2011

The Yacht Marquesa

Dave's boat, the Marquesa.

I met Dave in November at Mariner's Cafe in Ha'apai, Tonga. I was looking for a ride to New Zealand and he definitely wasn't looking to give anyone a rid. But somehow, nudged along by the prompting of the friendly cafe owner who was perpetually giving him a hard time, and in light of the fact that I was weird enough to go to Antarctica, Dave grudgingly agreed to take me on for the crossing...

Since then, I've been traveling the South Island, and all the cruisers like Dave have been holed up in North Island ports like Opua and Whangarei, waiting out the South Pacific hurricane season and futiley trying not to go broke in New Zealand. In May, when the weather improves, people will start heading out for Tonga, Fiji, Vanuatu, and other exotic destinations.

After a month volunteering in Christchurch, I'm back on the North Island, ready to do whatever grudge work might come up when the Marquesa gets hauled out for maintenance tomorrow... !

Wednesday, April 6, 2011

Whangarei Oil Refinery

NZ’s only oil refinery is located at Whangarei Head- an area deemed to be geologically stable and conveniently located.  Tankers from the Far East, Indonesia, Australia, and NZ deliver up to 130,000 tons per load- enough to run the refinery for 10 days.  The crude is stored in 2 mil gal and smaller tanks. 
From there it is boiled and the resulting gas is pumped to the distillation columns where its various components condense onto trays.  Products with high boiling points, such as residue, heavy gasoil, and light gasoil cool quickly and condense low in the column.  Higher in the column kerosene, gases, TOPS, and naphtha are deposited on trays.  Light and heavy gasoil will be refined into diesel, kerosene becomes jetfuel, and TOPS and naphtha become petrol.
From here the products are forwarded to desulphurization plants.  Under heat and pressure in the presence of a hydrogen catalyst, sulfur is separated in the form of toxic H2S gas. 
Next, the platformer utilizes a platinum catalyst and hydrogen to raise octane levels from around 50 to standard 91 and 95 petrol levels. 
Elsewhere, the Long Reside from the original distillation column goes through the most complex series of treatments.  First, it is pumped to a High Vacuum Unit, where  Waxy Distillate and Vacuum Gasoil rise up a column under vacuum conditions, and leave Short Residue at the bottom of the column.  This Short Residue goes to the Butane De-Asphalting Unit, where it meets a counter flowing stream of hot Butane.  The lighter components are absorbed into the butane and leave the top of the column.  Heavy asphalt components remain.  These are further distilled in a High Vacuum Unit to produce Bitumen.
The plant features a hydrogen manufacturing unit where a catalytic furnace combines butane, plat former gas, and steam to produce hydrogen gas.  A byproduct of this process is CO2 gas, which is sold for soft drinks. 
The Hydrocracker is the heart of the refinery.  Inside four giant reactors, under great pressure and heat, long hydrocarbon chain molecules are broken down (‘cracked’) into shorter chians.  This process turns  the heavy waxy feed into petrol, kerosene, and diesel components. 
Waste sulfur dioxide gas form various processes is transmuted to liquid sulfur, which is transported by road tanker to a Whangerei plant where it is used in the manufacture of fertilizer.  Old systems recovered 96% of sulfur, and new improvements have upped that number to 99.8%.  In order to depressure the plant, gases are disposed of safely using 90m high flare stacks, where a pilot flame burns continuously. 
End products are pumped down the 10” Auckland pipeline at the rate of 400,000litres/hour. 
The New Zealand Refining Company Ltd is one of the biggest employers in the Northland area, with 300 staff and up to 180 contractors on site.