Friday, 17 May 2019

ANALYSIS OF WRECKAGE DISTRIBUTION.

Wreckage was first discovered in the form of two copper air tanks (from lifeboat(s)) on North Turtle Island, 25 March, by Mr. Daniels of lugger Gloria Violet. The majority of wreckage was discovered between 2 and 5 April, a fortnight after the disaster. The final discovery during this time frame, also copper air tanks from lifeboat(s), mid April, is outlined in the following report: 


The West Australian, 17 April, 1912.

THE KOOMBANA.
A STATIONOWNER'S REPORT.

Mr. W. E. Moxon, manager of the 
Adelaide Steamship Company, received 
information yesterday to the effect that a Mr.
Thompson, a station-owner in the North
West, had reported that some of his natives
had picked up three copper air tanks, which
had evidently come from one of the life
boats of the Koombana. The tanks were
found on the sandy beach connecting 
Solitary Island with the mainland, slightly to
the north of Amphinome Shoals.

Three sets of air tanks, originating from the wrecked Koombana's lifeboats, were discovered close to the coast, comprising 3 widely spaced (100 miles) geographic locations:

13. North Turtle island
14. Solitary Island. 
15. 14 miles south of Port Hedland 

There is no specific pattern apart from the air tanks having been subjected to the "set-in of the tide" -  Captain Clark, formerly Chief Officer of the Koombana:


"the wreckage had been borne landwards 
by the set-in of the tide, which always 
followed on a severe blow in the
Fix this textnorth-west."

One might anticipate such an outcome given the buoyancy factor associated with air tanks and variable surface wind forces.






Alternatively the Solitary Island discovery could point to what drover Olive saw on the night of 20 March.

Daily Commercial News, 14 May, 1912

The company had received a report 
from a magistrate at Broome that a 
statement had been made by a drover 
named Olive, that on the night of March 
20, when he was at Boyer's Camp, 30 
miles north of Condon, at about 8 or 9 p.m. 
he saw two rockets go up in the direction of
N.W. There was a hurricane blowing at 
the time. 

From a position on low cliffs roughly 46 ft. above sea level, he claimed to have seen two rockets in the direction of the northwest. Veracity of this account depends on reasonable visibility and the rockets rising to a significant altitude.

It is possible that at least one lifeboat got away safely from the sinking Koombana and these rockets were fired from it, which might explain why copper air tanks from such a lifeboat ended up at Solitary Island; a direction contrary to the sites of the other two sets of air tanks. 

Could it have been Koombana in the position of the two rockets rather than  a lifeboat ?

The vicinity of the rockets is riddled with shoals, notably the Amphinome Shoals and is relatively shallow. If Koombana grounded or foundered in the vicinity, surely the wreck would then have been readily discovered by fishermen, spear fishermen and pearl divers through the decades?

The distribution of the bulk of wreckage does not favour this site, particularly with the set-in of the tide referred to. (see second image and discussion below).

Against the veracity of drover Olive's account is the fact that during the night of 20 March and thereafter, the 'hurricane' was to the south of Port Hedland, not north. 




Let us return to the distribution pattern of the bulk of wreckage discovered.

Important to note that wreckage was found in close proximity to the Upjohn coordinates for the oil patch:

Daily Commercial News and Shipping List (Sydney) 14 May 1912.

They had taken the specimens produced 
in court at this spot. An awning spar and
one of the planks exhibited in Court had
also been discovered in close proximity.
Other articles were picked up about 20
miles from that spot (marked 2 and 3
on graphic below).


27.5 miles represents 30 fathoms, 20 miles from wreckage 2;3.


1. Stateroom door; painting stage; small pieces of board. SS Gorgon  
19 10 S, 119 06 E
2. Motor launch starboard bow plank (with insignia). SS Bullarra   
19 15 S, 119 06 E
3. Small wreckage; (life) boat tanks; lifebelts; panel from saloon / smoke room ceiling. SS Bullarra
(see: https://koombanarevisited.blogspot.com/2019/11/sufficient-warning.html) 
19 15 S, 119 06 E
4. Bottom board from (life) boat; white painted board. Lugger McLennan.  
19 22 S, 119 05 E 
5. (life) boat mast and small wreckage (rising from bottom). SS Una   
19 07 S, 118 53 E
6. Miscellaneous wreckage. SS Una  
25 miles NW Bedout Island. 
7. Miscellaneous wreckage. SS Una.  
28 miles NW Bedout Island.
8. Cabin paneling. Lugger Mina.  
19 30 S, 118 55 E
9. Smoking room cushion; cabin door. SS Minderoo.  
19 36 S, 117 53 E 
10. Straw envelopes (Leech's fortune). SS Minderoo and SS Gorgon.  
55 miles NNW Port Hedland.
(see:  https://koombanarevisited.blogspot.com/2019/11/sufficient-warning.html)
11. Bottom boards (lifeboat); drawer; small teak panel. SS Minderoo.  
19 32 E, 118 09 S


North of Bedout Island the prevailing current generally flows in a westward direction - Holloway Current (100m).


By my deduction, the distinct cluster of wreckage drifted from east to west and it is suggested that the starting point was somewhere in the vicinity of Captain Upjohn's oil patch coordinates - the site of the wreck of RMS Koombana, further substantiated by the above report reference to a spar awning and one of the planks found in close proximity to the oil patch.

In this instance, the heavier, waterlogged items do not appear to have been significantly influenced by variable, prevailing winds, as were the light and buoyant air tanks.



note extent of Balla Balla cyclone


Long after the disaster, discoveries were still made:

12. Submerged bilge section 150-200 ft.. SS Bullarra, mid July, 1912.  
20 10 S, 118 03 E
16. Saloon seat and ladder. Schooner Queenie Alice, July, 1913. 
Between Forestier and Depuch Islands.
17. Second stateroom door. Pearler, Sholl Island, 1930's.

It is clear from this pattern that over time wreckage drifted inshore, further down the coast (not up the coast).


The Sun, Kalgoorlie, 31 March, 1912.
TELEGRAMS
THE UNSUCCESSFUL 
SEARCH

PERTH, Saturday.
Five steamers have been searching
all the week for signs of the missing
steamer Koombana, have discovered 
no trace. Turtle Islands, Bedout Island 
and Ninety-Mile beach have all been 
carefully examined without success. 
The steamer Minderoo, which left Onslow
for Cossack on Thursday last is now 18
hours overdue. Some optimistic people
regard this as hopeful, thinking she may 
have the missing steamer in tow, but the 
general feeling now is that the Koombana
went down during the recent cyclone. The 
search is being still continued.

The report emphasizes that during the initial two weeks after the disaster, no wreckage was discovered. This suggests that wreckage was released after some delay from the sunken wreck rather than immediately due to battering hurricane-force winds. 

The following extract illustrates the Pilbara current trend associated with Western Australia cyclonic events such as the Balla Balla Blow:  

'alongshore propagating cyclones are responsible for simultaneously generating both strong wave‐induced sediment re-suspension events and significant southwestward subtidal currents. Over the 2 year study period, two particular cyclones (Iggy and Narelle) dominated the sediment fluxes resulting in a residual southwestward sediment transport over the southern part of the shelf. By analyzing results from a long‐term (37 year) wind and wave hind cast, our results suggest that at least 16 tropical cyclones had a strong potential to contribute to that southwestward sediment pathway in a similar way to Iggy and Narelle.'

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017JC013518

11 March, 2021, cyclone Seroja devastated Kalbarri, Western Australia. 

To support my assumption that the bulk of Koombana wreckage drifted generally westward (west-southwestward in some cases) from an assumed starting point of the Upjohn oil patch, I looked at daily surface currents data for the Pilbara to correlate with a post-cyclone model for time of year, such as that outlined above.

The following images document this data as per dates reported.


17 April, almost 1 week after cyclone Seroja: -

Port Hedland is located halfway between 118 E and 119 E.
Bedout Island, 35 miles south of the 19 S line, is roughly where the 'LL's' of Wallal appear on the graphic.

Generally, the currents trend westward and southwestward.
There are no indications of an eastward trend except for a single outlier in latitude 19 S, well beyond the range of Koombana wreckage coordinates.




17 April, zooming in: -

The current trend between Port Hedland and Bedout Island is unambiguously westward.

(Bedout Island is roughly where the  'LL's' of Wallal are marked on the graphic)




19 April: -

The same pattern persists, the area directly north of Bedout Island demonstrating a clearly southwestward trend.

No indication of an eastward current trend.





20 April: -

The southwestward trend north of Bedout Island remains unchanged.




21 April: -

The consistent, westward trend supports my initial assumption that Koombana wreckage drifted uniformly from east to west.




23 April: -

Unchanged.



24 April: -

Unchanged.


26 April: -

15 days post Cyclone Seroja, the current trend both north and south of Bedout Island is consistently westward. 



3 May: -

In fact, 22 days post cyclone Seroja, the trend remains unaltered!!



'Captain Mills, of the steamer Minderoo, 

is inclined to the belief that the ship was 

lost in the vicinity of Bedout Island.'

 


Captain Mills picked up the smoking room cushion, among other items, some 55 miles to the west of Bedout Island. His contention that Koombana lay in the vicinity of Bedout Island confirmed the fact that the current carrying the wreckage trended southwestward.


The following extract (one of many period experiments conducted) illustrates the significance of prevailing currents' relationship with drifting objects. The distances in this extract are roughly 3,000 and 1,150 miles respectively; the prevailing current in question being the Southern Ocean Circumpolar Current from west to east:

 

Daily Telegraph, 19 January, 1911.

BOTTLES FROM THE PERICLES
HOBART, Wednesday. — Fishermen have
picked up two bottles containing current charts,
which on December 26 and 31, 1908, were thrown
overboard from the steamer Pericles, which was
wrecked off the West Australian coast. A peculiar 
feature about the find is that the bottles were thrown 
overboard with an interval of five days between each 
and they were found within five or six miles of each 
other on the South Tasmanian coast.












Thanks to Annie Boyd for contributing to wreckage data.



courtesy Trove; Google Earth and:

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