What Alice Saw

Enter if you dare; opening to No3 oil fuel tank

Enter if you dare; opening to No3 oil fuel tank

Being in a sunless space, bereft of fresh air for last three years, does strange thing to people.
After picking up the entry permit from the project office our thoroughly serious and professional marine hull surveyor, Warwick Thomson, is intently checking that the tank has been gas freed correctly; he sorts out the essentials, gas monitor… check, camera, torch… check, chipping hammer… check, note pad and pen… check check. Clothed in his fresh, white disposable overalls, Warwick could be mistaken for a slightly dumpy cottontail but afflicted with the difficulties of Alice in negotiating the entry down the rabbit hole of No.3 fuel oil tank. In its shape, the fuel reservoir is a crescent moon prism, its inboard surface being the regular cylinder of the pressure hull, its outer more complex curve, being the thinner plated skin visible from the exterior of the sub. Internally, the space is complicated by a lattice of supports radiating from the inner to the outer lateral face.

Down the rabbit hole; ladder in No 3 oil fuel tank

Down the rabbit hole; ladder in No 3 oil fuel tank

After edging past the coming, Warwick heads to the side and upwards, inspecting the critical edge that, externally, has been of much concern (see blog, Day Two; Between the Times) but any disquiet felt over the potential state of the internal structure has been found to be misplaced. The area is in near pristine condition with only about two percent surface corrosion and no wastage of either the pressure hull or the outer tank shell. Nearly all of the corrosion present in the tank appears around and directly below the entry point where remedial work being undertaken will eliminate any further ingress of rain water. The continual harsh tap of hammer to steel, as our Professional troglodyte tests the integrity of any suspect area, acts as a reassuring heart monitor, but as Bunny Thomson makes his way outboard down the first ladder then crosses over to the second to head in, down around the tightening lower radius and out of sight, a mad high pitched cackle is heard.
“Tis the annular holes of the tooth brush that’s checked annually, hee, hee, hee”
Has he gone insane, overcome by remnant diesel fumes or has he partaken of the “eat me”, “drink me” temptations at the bottom of the rabbit’s hole?
The grimy white whiskered face of Warwick, appearing through the tank top, bearing a broad smirk, informs me the it is  neither diesel nor potions that have caste this madness upon him, it is simply the latent-naughty child within, delighting in the novel adventure of being somewhere he shouldn’t really be. The regressed marine surveyor was just testing out the acoustics by sounding out a rendition of Spike Milligan, The Goon Show, circa 1958.

Bunny Thomson in No1 water ballast tank

Bunny Thomson in No1 water ballast tank

With few exceptions all the fuel oil & water ballast tanks as well as the free flooding areas have been found to be in remarkably good condition with little or no deterioration of the surface coatings. Even No 1 water ballast tank, open from the last docking, had but little marine growth. Although the discovery of a saucer sized oyster on the internal structure promised a rare treat, the thick sludge oozing beneath my feet made me think better of it. The sub hadn’t bottomed since being at the museum; the black tar like matter, slowly swallowing my feet, had simply formed by suspended, water borne particles, settling in the sedate confines of the tank. I instantly desired to send a sample off to some lab, perhaps a cure for cancer would be found in this concoction which smelt of three day old marinara with a case of sun stroke, but more probably, yet another cause would be identified.

There was an element of envy in losing out on the oyster, for it seemed that everyone else had been able to partake of the oceans offering. As the pump down of the outer dock drew to a close a mild frenzy took place at the base of the outer caisson. Plucking brim and flat head, from the grasp of the graving dock pumps a flock of  labourers swooped upon there forlorn prey. It is a time honoured tradition here “the docking fish haggle”, where, using dockside Esperanto and gesticulations, each man argues for his fair share, a regular bonus for these unfashionable labourers who possess a sense of irony and love for the great Australian sport of tax avoidance; as one old hand gleefully explained.
“There’s no fringe benefit tax on this lot, mate”.

No1 water ballast tank, free flood holes sealed

No1 water ballast tank, free flood holes sealed

They Came They Saw… They Painted

Onslow prior to the application of primer

Onslow prior to the application of primer

A quick spray down before painting

A quick spray down before painting

In the early morning and aft of the clock watchers end, the dock floor is moist and cool. At mid day dining time, again she’s placid, humidified by the latent pools and the gentle cascade edging by the outer caisson. The sheer thermal mass of a structure, that when completed, at the eve of peace in the 1944, could house any vessel afloat, ensures a mild clime, while Onslow’s constant shadow gives respite at midday to our more freckled fellows. At these times there is only the interval led, discordant pop of the compressed air relief valves, not too far removed from a croak, to disturb the air. But these are only moments among many and the sudden vision of a soul, accompanied by paramedics, being hauled aloft in a yellow cage through the vacant blue, reminds you that when you’re down and out at the bottom of the dock there’s only one way out; forty five feet up straight up. He’ll be okay, the pain killing shots have subdued him and after a couple of weeks of physio he’ll be back but for the rest of the day you’re left hypersensitive to the need to know, to be sure of every placing of the three points of contact, to follow the rules, to know that some one else knows where you’re at, for on the irregular floor of the dock, strung out with hoses possessing their own dynamism, with multiple bobcats and remotely driven cherry pickers all  beeping out a warning that builds  to a Doppler cacophony, then splits into asymmetric chaos of sound, to be heard, to be seen, to be safe, is never guaranteed.

Coolade Acid Test, paint preparartion

"Electric Coolade Acid Test", paint preparation

The sub, has of late, adopted the manners of a chameleon, changing at every new glance. The preparation work left the hull with a temporary psychedelic camo. pattern that the merry pranksters would be proud of. Within a day it disappears below a coat of sealing primer, green / bronze in hue on the steel topsides and a stark white primer for the GRP fin. Seven men work as one to progress the painting. The ever smiling Humphrey coordinates the process from the dock floor; he has two colleagues at his side supplying a continual flow of the synthetically sweet smelling liquid to the basket of each cherry picker. While the sprayer applies overlapping two meter runs the driver perched beside him directs the platform through three dimensions so as to offer a fresh surface to the sprayer on each pass. Roughly apace of each other, the long necked vehicles, on either side of the sub, seem locked in a reptilian dance, advancing only after numerous jolting rocks of their body.

Spray team in action

Spray team in action

Now that the majority of the prepared surfaces have been sealed, work can commence atop of the pressure hull, readying the more intricate areas for paint… well not quite yet. If you recall, the last blog post detailed the candy pink desertification of the dock, well those pretty little grains of garnet have entrenched themselves in every nook, every possible crevice and improbable cranny and yet again cheery Humphrey’s and his team appear, ready to do battle. Like an unseen army of banister brush ants they push forth mounds of earth, mined from beneath the casings, onto the tank tops from where it topples down like pink rain. Days and days of rain spray out from the teams nozzled hoses in a laborious attempt to depose any remaining gem grains tenaciously clinging to there setting. While the wash out continues little progress is made on painting, the only obvious change is the handy work of a isolated couple elevated to face the fin, filling each of the hundreds of bolt holes with a Laminex green, epoxy filler. There could be problems, the liberal application of the bog will multiply ten fold the sanding needed to gain a flush surface and at this point, time is not a commodity we have an abundance of.

Painting the fin

Painting the fin

And some yet more painting

...and yet more painting

Day Two; Between the Times 17/10/2008

Onslow entering Captain Cook Grave Dock

Onslow entering Captain Cook Grave Dock

Today is much like the last only lacking all the fanfare. Again, our Navy pilot boards and the DMS tugs come along side. Under the watchful eye of the jaunty dockmaster we’re eased into the Captain Cook Graving Dock, one of the true industrial cathedrals, but today it looks more like an over sized swimming pool. Secured well back in southern eastern corner of the dock, Onslow will stay in this position until the pump-out of the dock commences next Friday, being joined by the museums light ship  CLS 4 (commonwealth light ship) and thales’ floating dock. There is not a lot happening for the rest of the day so I’m off back to museum to organise some supplies.

CLS4 being manoeuvred within the garve dock

CLS4 being manoeuvred within the garve dock

This seems a good time to discuss the work that will be undertaken during the following week, but first, a bit of ‘submarines for dummies.’ Essentially, the submarine is a habitable metal tube (the pressure hull) which gains buoyancy from the saddle tanks attached to the greater part of either side of the vessel. As I explain to our younger guests at the museum, these tanks are much like floaties, when full of air the sub remains on the surface. Release the air and she submerges below the waves. Luckily all submarine have the ability to re-inflate their floaties and re-emerge on the surface.

The next point is that what you see is not what you get with a submarine. On the surface she appears to be ominously sleek and other worldly but lift the bonnet, or more accurately the casings, and much of the mystery is removed. The casings, over twenty in number, sit atop of the pressure hull and run near the full length of the hull. Made of either mild steel or GRP (glass reinforced plastic) their primary function is to give the submarine a hydrodynamic shape; they also provide protection for the equipment that lies below them as well as giving a work platform when the sub is surfaced. Compressed air bottles, exhaust manifolds, sonar arrays, webs of pipes and a menagerie of equipment are housed underneath the casings. With their removal, many of the functions of the sub and the means with which they are attained come to light. The dark menace is shown to be just a bunch of nuts and bolts, although a very a very complex bunch.

Channel, where saddle tanks and pressure hull meet

Channel, where saddle tanks and pressure hull meet

Onslow; featuring saddle tanks and casings

Onslow; featuring saddle tanks and casing

So why does Onslow needs to be docked? The three main aims of the docking are to make sure she remains afloat, preserve the vessel’s exterior and to improve the boat’s aesthetics. These three aims are intertwined. In this first week, prior to the pump down of the dock, the lifting of eleven of the GPR casings will be the main event. This will allow access to areas that would, without a team of highly trained spider monkeys, be impossible to reach, and its purpose involves all three aims. One of the critical areas, in regard to buoyancy, is the point at which the saddle tanks join the pressure hull. The surrounding area forms a gutter, collecting water and leaving it susceptible to corrosion and the possibility that the tank’s watertight integrity could be breached. It is essential that this area be well preserved. If the casings were left in place there would be very restricted access and a great risk of the fibre-glass casings being damaged from the water and grit blasting that will take place later. The blasting will remove most of the corrosion on the pressure hull and pipe work, in preparation for preservation via painting. With the source of most of the rust staining along Onslow’s sides no longer present, she will look better for longer and will probably have lost a couple of kilos. The docking is much like the combination of a detox diet and trip to the day spa, you’re healthier, you look better and it often stops that sinking feeling.