The Royal Research Ship 'Discovery'. Part 17.

In the Bowels of the Ship

It occurred to me when working in the hold (inside bottom) of the ship one tends to ignore, or perhaps forget, what lies on the other side of that inner hull. Discovery was, for much of the first half of the Project, in dry-dock so the air in the hold was, by and large, the same as that on the outside. When she was afloat the level of the water on the outside was 12 feet (3.7 metres) above the keel, in other words nearly six feet (1.8 metres) above the average person's height. The deeper the water the higher its pressure, so all around the ships hull the water was pushing from the outside trying to get in. Ships, all ships and boats, are designed to withstand this pressure and so float. An interesting and perhaps more frightening statistic is of the deepest drafted oil tanker ever (now scrapped). When fully loaded the depth of water from her keel up her sides was 93 feet six inches (28.5 metres). Imagine working in the bottom of her engine-room of that ship knowing (or forgetting) that the depth of water above your head on the outside is nearly 88 feet (26.9 metres). Quite a thought!! So visitors when touring around the Discovery's hold spaces remain blissfully unaware that they, in fact, are walking underwater. I suspect those who may be of a more claustrophobic nature would want to get out quickly!

I told of the two-dimensional replica packing cases that shut out the ventilation in the previous part of this story. The following pictures show these again at the beginning of 2008.

The middle and bottom of these three pictures show the massive beams that run
across the ship that had been cut many years before to allow an unrestricted passage through the hold of the ship.

I promised I would show more of the unique construction of Discovery in relation to the magnetic free area around the observatory. This area was situated just forward of mid-ships (forward of the centre of the ship) and had a radius of 30 feet (9.15 metres). When the replica packing cases were removed we found large, forged, naval bronze, beam knees (metal angles that tied the cross beams to the vertical frames). We knew they were there of course but they had been hidden by the false replica wall for years. Not only that, the damp conditions around them allowed electrolytic corrosion to attack the fastenings and in places the inner planks showed signs of breaking down to their chemical component parts. The Lignin or Lignen (the component that holds the fibres of timber together) had been the first to suffer leaving cellulose residue of the fibres coating the outer surface.

The cellulose granules are on the left of the picture and the timber fibres on the right.

The Naval Bronze beam knees cleaned up. The pigeon holes between are described in the narrative.

As the false partitions were taken down, the inner ceiling (that's the naval term for the side) dried, cleaned and coated, the whole of the atmosphere in the lower hold changed significantly. Not only was the ventilation restored but the whole of the wooden construction elements were made visible. In the picture of the beam knees above you will note openings (I call them pigeon holes) between the frames of the ship. This was another secret of those who designed her and makes one realise that in 1900 the preservation of timbers on the outer and inner hull of the ship was uppermost in the mind of the architect who was involved. He knew that Rock Salt, and salt generally, had preservative qualities in relation to timber. It is a very fine line between decay and preservation so far as water is concerned. Fresh water with a density of 1,000 g/cm3, is harmful to timber; whereas salt water at a density of 1,025 g/cm3 acts as a preservative. Knowing this and knowing that the upper deck of the Discovery would, through the stresses placed upon it, leak from time to time, even though the Bosun would have had a running plan of repair and maintenance. So rain water would find its way down the ships side of the inner hull and, if left untreated, would slowly eat away the timbers. The treatment involved crushed Rock Salt being fed through the pigeon holes to form a barrier between the inner planks and frames, right from the upper deck to the bottom. So the cunning plan evolved! The fresh water that found its way between the frames and planks at the upper deck level, as it seeped down it was absorbed by the Rock Salt and slowly turned from a fresh to a saline solution.

A walkway having been constructed much earlier through the holds of the ship to allow visitors to safely travel through, doors had been cut through the once watertight bulkheads ( a bulkhead is a solid construction that runs across the width of the ship at designed intervals). How these bulkheads were constructed is another feature of note. They were built of Pitch Pine, double diagonal planking, not conventional vertical or horizontal aligned but diagonal with the diagonals on one side running in the opposite direction to those on the other. this gave the bulkhead a very strong resistance to horizontal forces. If an individual compartment should be flooded by accident or design the ship would remain afloat supported by the buoyancy of the other compartments since the flood water would have been contained between two watertight bulkheads.

This photograph shows the diagonal planking on what was the watertight bulkhead at the forward end of the coal bunker
on the starboard side. The people in the blue overalls are real, the one on the left is a dummy stoker holding a shovel lending a hand!

Next we enter the world of high-tech, bringing the modern methods of gathering information and using it to best advantage in the conservation of the ship.