Marine-Archaeology/history

what date did Batavia dispatch

29th of October 1628

what cargo was onboard the Batavia

silver coins, 2 antiquities, and pre fabricated sandstone blocks for gate in Jakarta.

how many passengers were on board

341

Basic story of Batavia

• Left Holland on 29th of october 1629 to Jakarta

• Journey started with a storm that separated Batavia

• Reached Cape of good hope 1month ahead

• Pelsaert fell sick so spent most time in cabbin

• Jacobsz and Cornelisz distrusted Pelsaert

• Lucretia rape

• 4th june 1929 Batavia wrecked on Morning reef drowning 40.

• 180 peple ferried to beacon island but Peslaert and Jacobsz along with 48 others went to traitor island

• Pelsaert and officers found no water to went to Batavia (Jakarta) and arrive 7-8th July 1629

• When arrove Boatswain was executed and Pelsaert was arrested for negligence. a week later Governor Jan Pieterzoon Coen sent Pelsaert back but took him 67 days

• while away Batavia broke apart drowning another 40

• Survivors went to traitor island and beacon island. but due to departure of Pelsaert it made crew angry so Cornelisz picked 40 men as followers.

• Cornelisz planned to sieze any relief ship and take off and live life seeking sensual pleasures.

• Cornelisz had to eliminate remaining survivors so sent 45 to seal island, and then 15 to traitor island to look for water but knew they wouldnt return.

• then sent 20 soilders under command of Wiebbe Hayes to explore highlands but took weapons.

• Cornelisz downed many by sending them onto boats and pushing them overboard and organised remaining to be killed.

• rape due to lawlessness

• group at seal island were alive and found water so sent smoke signal that distressed Cornelisz as it would attract rescue ships.

• after failed attempt to persuade Wiebbe to join Cornelisz sent attack force but got defeated. (5 tied up and companions executed)

• 16th september 1629 pelsaert arrives back and Hayes gets to him first to explain murders and mutiny and he took cornelisz as prisioner.

• Went to Batavia Graveyard (Beacon island) and interrogated mutineers where 7 had right had cut off but Cornlelisz had both

• 2nd October 1629 put to death on seal island

• 5th december 1629, 116 remaining survivors retuned to Batavia. (322 on boat when wrecked, 125 murdered)

what day did survivors make it to Batavia

5th December 1629

when did Cornelisz die

2nd October 1629

when did Pelsaert arrive back to the wreck

16th september 1629

when did Pelsaert leave to go to Batavia

7-8th of July 1629

when did Batavia wreck

4th June 1629

how many survivors were there from Batavia (total)

116

how much later was Batavia wreck discovered

300 years later.

when was the first successful excavation of Batavia

1963

when did excavation begin

1972 over 4 seasons

when and what occurred in season 1 of excavation

• 1972-1973

• large amount of coral rubble had to be removed

• aim was to make a trench to see stratigraphy of site

• sandstone was investigated first as most raised

• stern selected for excavation as most protected area

• number of artifacts found increased closer to stern

• Timbers from northern port side of the ship was excavated

• by end of season cannon 1 and 2 were cleared of coral and cannon 3 raised and 5.5 of timber was recovered.

when and what happened in season 2 of excavation

• 1973-1974

• large amounts of concretion hindered the site caused by cannon balls

• many more artefacts found

• following concretion removal, more timbers recovered

• cannons 1 and 2 raised

• work was slow due to concretion so program put in place to collect pottery and bricks inside reef when diving on reef not possible

when and what happened in season 3 of excavation

• 1974-1975

• remains of stern post with water line marking in roman numerals found and raised.

• work continued on recover of transom, lodging knees, ceiling planking and frames.

• work was slow due to concretion going through layers of timber

• Fashion Piece (large timber supporting stern and transom) was recovered and was largest timber

• all stern timbers recovered and excavation of ships structure was complete

• numerous coins, iron objects found.

when and what happened in season 4 of excavation

• 1975- 1976

• season was difficult due to poor weather

• only 10 days of work possible on wreck

• more cannon balls and misc artefacts recovered

• 200 hours spend inside reef which was recovery of pottery fragments while also looking for new areas of wreck material.

how many days were worked on the wreck

447 total with 173 being on site

what are the 3 main conservation techniques used for Batavia

• transport and desalination

• PEG method

• Acid problems

describe the desalination and transport process for conservation of Batavia

• timbers kept on Beacon Island in make shift tanks (plastic lines holes dug in ground willed with sea water)

• transported to Freo by wrapping in hessian saturated with sea water then sealed in plastic bags

• in freo it was then placed in large desalination tanks (freshwater for 2 years)

describe PEG method

• treatment is used for 2-3 yeaes

• following PEG, timbers air dried using slow dehumidification process over 6-12 months

• PEG is a synthetic wax substance soluble in water and alcohol, it removes excess water while providing structure.

• can be corrosive so can’t be used in wood with metal in it.

• process;

  1. it is first cleaned of any dirt

  2. object is placed in a VAT container with PEG, water and alcohol

  3. temp is gradually increaesd to 60 degrees over time.

  4. % of PEG will decrease over time so more should be added as evaporates.

  5. it will eventually soak into wood removing all water.

  6. wood is removed from wax and excess is wiped off and cooled, if any wax is left after cooling a hot air gun is used to remove it.

describe acid problems in excavation of Batavia

• once a day on display timbers showered in acid formation due to the high relative humidity

• they had to be treated used gaseous ammonia

• gallery humidity was reduced and controlled

describe the general recording method for Batavia

diving hours, work time, sea state, and weather were recorded daily. artefacts recorded in find books and designted prefix number for material type

name and describe the underwater photography methods used

• site photomoasic: taking a lot of small pictures and putting them together. whole of Batavia was made in first season. 7 taught wires 1m apart and 46m long taped at 1/2m intervals placed along axis of wreck while photos taken at 1m intervals

• Timber photomoasic: same as site but with timbers and where they were placed. as timbers were uncovered they were labeled and photographed before surface layer was removed and under layer retagged and second moasic made.

• Stereophotography: 2 photos taken from slightly different angle to create depth. it is used to interpret complex structure areas and provide additional info

describe how wood was recorded

each piece of wood was tagged in situ. it was raised and stored in sea water tanks. indirect sunlight was best for recording. drawings made by tracing polythene sheets. wheeled on trolly for photos.

what are the main ways for locating a ship wreck (name and describe)

• historic records: first step in determining position of wreck and search area. e.g ship logs, journals, ect. it is useless to attempt a search if you dont kno if you are in the right spot.

• aerial: collecting images from a plane or drone, a series of pictures taken and allow image to be surveyed to research area. linked to photogrammetry where photos are taken an a map is produced

• magnetometer: measured earths magnetic field. waterproof surface either behind boat or low flying planes. when anomaly in surface it indicated Ferrous object. detectable fields called anomalies

• sonar:wide oblique sonar beam generated from transducer in a “towed fish” and directed out to sea floor. it returns signal and indicated projections.

Decay process of Siliceous material

pottery and ceramics will survive well in marine environment. cracking is cpmmon as those not impervious will absorb saly and crack wen crystals form. a layer of concretion can build up and iron oxide stains can become present

decay process of bone (organic)

can become water logged and become spongy

decay process of textiles (organic)

conservation is limited to natural fibers of origin. fibers that consist of protein are more resistant to decay. they are susceptible to attacks from bacteria and deteriorated by light and microorganisms

decay process of wood (organic)

cellulose in wood is eaten by microorganisms and wood borin organisms that use cellulose for energy. wood becomes water logged as it absorbs 850% more water wet than dry. sediment acts as natural defense.

name and describe the ways metals are broken down

• electrochemical; requires 5 conditions, an anode (corrosive), a cathode (non corrosive), contact between them so electrons can flow from anode to cathode, an electrode (solutions with ions), and a reactant such as dissolved o2 at cathode.

• Ferrous corrosion: electrochemical decay. iron corrosion= iron+o2 → iron oxide

• anaerobic corrosion: sulfate producing bacteria cause the corrosion. Sulfate bacteria found in environments where decaying organic material consumes o2 and creates anaerobic events. bacteria used hydrogen to reduce sulfates to sulfides. iron reacts with hydrogen sulfide to increases and accelerates corrosion which produces ferrous sulfide and ferrous hydroxide.

excavation techniques

1. probing: physical attempt to locate artefact beneath surface. done by a narrow tube that pushes air or water down at low force. they are capable of penetrating sediments more readily, although can damage artefact. aim is to make contact with item

2. hand fanning; use of persons and to remove sediment from surface.

3. water dredge/air lift: narrow hose that is sent to bottom of ocean to remove sediment. it allows controlled removal of sediment

4. brushes, tooth picks, hammers, chisels ect used to chip away at sediment

processing and recording while excavating

must have enough info in a systematic way that is accuratr and complete. needs spatial info, descriptive info, defining info, and temporal info (what happens). name of object, notes, measurements, drawings also need to be recorded.

recovery process while excavating.

is getting artefacts to the surface. if intact enough air can be filled in it and becomes buoyant. if not winches, cranes, plastic bags, and lift bags are used.

describe lift bags

they allow heave items to be lifted to the surface. it consists of a bladder brought to sea floor via ropes and the filling of air allows the artefact to lift. it continues to lift as when pressure decreases, volume increases. a diver must say with the item the whole time during ascend.

Calculations of how much air needed for a lift bag

• mass of water displaced= water density x volume of object

• apparent mass= mass in air- mass in water

• volume required= apparent mass/density of water

de-concretion conservation technique

• when delivered and x-ray happens to see what is inside

• mechanical cleaning (hammers, chisels) chip away at concretion as its most useful. \some calcuim carbonate can be rinsed in dilute hydrochloric acid to dissolve concretion but can take a while.

• it is then rinsed in deionised water, driead and a sealant is added (a material that protects and insulates metal from outside environment)

• it needs to me imperative, natural looking transparent, and reversible

• stored below 60% humidity

stabilization of wood

PEG method

Stabilisation of ceramics

• should be kept in solution found in.

  1. wet pottery

  2. remove concretion and insoluble with dilute acid

  3. rinse pottery to remove acid

  4. remove rust stains with 10% oxalic acid or 5% EDTA and rinse

  5. remove iron sulfide and organic stains by immersing in 10-25% hydrogen peroxide

  6. consolidate with dilute PVA and reconstruct

main ways of stabilising iron/silver

• must be kept wet to prevent corrosion

  1. Electrochemical cleaning: it halts and stabilises oxidation. 2 metals (one more reactive than the other) placed in electrolyte solution so more reactive metal loses its ions to the least reactive one, protecting the less reactive one (sacrificial anode)

  2. electrolytic cleaning: is the setting up of a electrolytic cell with artefact to be cleaned as cathode. consists of a VAT with 2 electrodes (anode and cathode) and contains electricity conducting solution called electrolyte. an electric current sent from an external direct power supply causes oxidation and reduction. the Anode (positive terminal) attracts the negatively charges/colloidal ions and oxidation occurs and oxygen is evolved. the Cathode (negatively charged terminal) attracts the metallic positive ions and reduction takes place. in reduction some metal ions on surface reduce to metallic state.