Maandelijks archief: juni 2015

Vietnam Maritime Archaeology Project – The stone anchor

Besides being great days for diving, the last 2 days of week two also proved that you should always expect the unexpected in Vietnam. With occurrences such as our boat unexpectedly picking up random people before transferring them to another boat in the middle of the ocean, this was a week full of surprises. However, while life in Vietnam remains peculiar, our project steadily continues!

Our main site for diving this week was near a stone anchor, probably Arabic of origin. This stone anchor was found during surveys last year but its location was forgotten. It was therefore important to re-find the stone anchor site and properly map it for future research. Thankfully, vague memories of its location were preserved in the memories of some of the (previous)participants, making our lives a lot easier. After knowing roughly where to go, we send a number of snorkelers into the water to locate the anchor so we could begin our research.

Blog 6 Vietnam 02

Locating the stone anchor happened surprisingly quick, with it being located within 20 meters of where our boat was anchored down at a depth of about 9 meters. Within minutes one of our teams was in the water to take the GPS co-ordinates. Research of the anchor itself was conducted after which a survey of the surrounding area was done to find any possible related artefacts. This research was executed through a circular swim-line search and delivered some minor results with a number of metal and ceramic artefacts found within 15-40 meters of the stone anchor.

Blog 6 Vietnam 03

While the divers were busy working on the stone anchor, our snorkelers managed to find a large number of ceramic artefacts near the shoreline. Due to the fact that these artefacts were washed up in more shallow areas of the water, full scuba gear was not required to investigate this site. However, to make sure we had researched the entire area, a number of swim-line searches was set up in the deeper areas near the location of the ceramics. This was followed by a thorough mapping of the visible ceramics by the snorkelers.

Blog 6 Vietnam 04

All in all this week was a rather successful week with a number of improvements for all of the teams. The execution of the survey techniques has drastically improved since the start of the first week, and the results are there to show for it. All in all, If the teams keep improving as they do, week 3 and 4 should be great weeks for the project!

Blog 6 Vietnam 05

Greetings from Hoi-An,

Mike

 

Vietnam maritime archaeology project – Fighting the Silt

While the weather has taken a turn for the worst, the project steadily continues. During week one the main focus was on all the different people getting accustomed to each-other and practicing our underwater surveying skills. Week two is all about putting these skills to the test. Furthermore, this week marks the first archaeological dives for some of the recent recipients of a diving certificate.

Diving is however not the only aspect of this project. Another similarly important project is processing the different artefacts this project might turn up. An important tool in processing these artefacts is named 3D photogrammetry. This “tool” turns your photos of an object into a digital 3d rendition which can then be send to, and researched by, professors, experts, and other people from all over the world almost as if they had access to the physical object. This makes it a lot easier for experts from outside the project to give their input and quickens the research process. The teams have been practicing this rather successfully on some of the artefacts present in one of the local museums with incredibly detailed results.

3D rendering of one of the 15th/16th century artefacts in the museum
3D rendering of one of the 15th/16th century artefacts in the museum

Another important aspect is understanding the Vietnamese maritime culture and giving the trainees in this project a number of reference points that they can look out for under water. The groups where therefore sent to a number of different boatbuilding-and-repairing villages surrounding Hoi-An where they were shown the specifics of Vietnamese boats as well as how they are made and repaired. Apart from being a very interesting process, it also helped to create an understanding of Vietnamese maritime culture which will help the trainees while they are out in the field, or in this case out in the ocean.

Simultaneously to these other activities, there were of course also people diving near the wonderful Cham islands. After a rocky start this week, with weather that prevented us from diving on Monday, Tuesday and Wednesday proved to be a lot more eventful. Tuesday was spent at our usual diving spot of “around the corner of Bai Lang Bay”, which still requires a lot more research. While nothing of notable interest was found the teams did manage to GPS-map the bay which will make it easier to mark/reference any future points of interest on a map and prevents us from losing track of where all our different archaeological artefacts and sites are.

Wednesday proved to be a more eventful day as we were forced to move to a different site due to the Vietnamese military having target practice at our usual location. with both of the diving teams finding numerous artefacts at the bottom of the ocean, this day soon proved to be rather successful. While after some more thorough research it seems unlikely that these artefacts are old enough to be of use for our research, it does show us that our teams do a good job and manage to pick up on any irregularities on the sea bottom.

Some of the divers on their way to the site
Some of the divers on their way to the site

Finally, while our diving teams were out scouring the bottom of the ocean, our Australian one-man snorkelling team (I’m talking to you, Ian) managed to find a possible new archaeological site with a number of, by the looks of it, very old and certainly very interesting pieces of ceramic alongside some very interesting sea-life. This surely was a site that we will have to research again in the near future and that might lead to some interesting results.

A very surprised eel
A very surprised eel
Blog 5 Vietnam 07
One of the found pottery shards underwater

Greetings from Hoi-An,

Mike

Vietnam maritime archaeology project – Hoi-An special

Hoi-An is a beautiful city located on the east coast of central Vietnam. Consisting out of a beautiful historic city and an ever growing modern part, Hoi-An was rightfully chosen to be considered a UNESCO world heritage site. However, the city’s appeal comes not only from the historic inner city, but is also derived from the fact that it ’s a hub for divers, snorkels, and sightseeers to go and visit the nearby Cham islands.

Blog 4 Vietnam 02

The historic city of Hoi-An dates back to the 15th-16th century. It was originally a minor trading village in the 15th century with some Portuguese influences throughout the 16th century. It wasn’t until the end of the 16th century that Hoi-An really started flourishing under the Nguyen lords. The commercial interest of these lords was unprecedented in Vietnam in that period and under their rule Hoi-An became a major player in Vietnamese trade relations. Traders from Portugal, England, China, Japan, and more all flocked to Hoi-An to share in the profits. This turned the city into one of the most important trading conduits between Asia and Europe.

Blog 4 Vietnam 03

Hoi-An’s status as UNESCO world heritage site is also closely linked to the city’s demise as a major trade port. Nearing the end of the 19th century, alongside the demise of the Nguyen lords, Hoi-An ceased to function as a major harbour. An important reason for this was the fact that the river alongside which Hoi-An is situated silted up at it’s river mouth making it almost impossible for ships to reach the city. While this meant that trading with Hoi-An ceased, it also meant that the city was largely sheltered from outside influences. Because of this most of the city has remained almost untouched since it started functioning as a major port and many of the buildings dating back to this period still remain standing. This makes Hoi-an one of the only cities in Vietnam with an almost fully preserved “old town” with many of the old homes and warehouses still standing and accessible to the public.

Blog 4 Vietnam 04

While the land-based cultural heritage of Hoi-An is under strict protection, the same cannot be said regarding the underwater cultural heritage. Vietnam’s underwater cultural heritage is still an underrated aspect of Vietnamese society and is commonly subjected to looting, salvaging and natural degradation. The main reason for this is because the underwater cultural heritage does not draw nearly as many visitors to the country as the land based cultural heritage does, and therefore does not bring in enough money to warrant a protected status.

Blog 4 Vietnam 05

The Vietnam Maritime Archaeology project hopes to change this carelessness regarding the underwater cultural heritage by showing what sort of cultural wealth is hidden underwater. The city of Hoi-An is a perfect base of operations for this as it is easily accessible from all over the world and has a lot to thank to its underwater cultural heritage. Furthermore, Hoi-An has many museums showcasing the treasures found underwater. Finally, the city is also an important hub for our project as not does it have its own underwater cultural heritage, it is also relatively easy to access a plethora of other different sites from the Hoi-An harbour. With the Cham islands being one of our most important dive-sites, only 30 minutes by boat away from the harbour.

Blog 4 Vietnam 06

Hopefully this project will manage to garner attention for Vietnam’s (And specifically Hoi-An’s) underwater cultural heritage by showing the country what it has to offer which can then in turn be used to educate a new generation of archaeologists and cultural heritage specialists.

Greetings from Hoi-An,

Mike de Booij

Oostvoornse meer day 11 and 12: Wrapping up

Having finished most of the mapping and recording of the western side of the wreck yesterday, today we have focused our efforts on the eastern side. In order to map this part of the wreck site we first placed more coded targets before shooting additional video footage for photogrammetry modelling. After every part of the site had been accurately documented, selected timbers were then chosen for dendro sampling.

Dendro sampling also continued on the western part of the site, where our divers faced the time consuming challenge of sawing through the massive keel timber.

Keel with datum point and coded target
Keel with datum point and coded target

There were also some other suitable planks for dendrochronology scattered across the wreck site so we’ve spent most of the day selecting and bringing up more dendro samples.

Day 12

Our final diving day was devoted mainly to ensuring we didn’t miss any measurements or critical construction features and lastly cleaning the site. The coded targets were carefully removed and the last dendro samples were lifted and stored. We have left most of the datum points (numbered points for the basic measurements on site) on sites for future reference measurements.

DSC_6074

Back on deck we made sure a full backup of all our data was made; over the course of two weeks no less than 330GB of video footage was recorded. In the following weeks this data should allow us to make an accurate digital 3D reconstruction of both wreck locations.

We finished diving at noon so we could weigh anchor and sail the work barge back to the shore where it will be picked up tomorrow.

The work has finished here. We go back to Amersfoort to process the data and do some further research on the material we gathered. The 3D photogrammetry that we have used to map the OVM 10 and 12 will make this work probably much easier!

Next fieldwork in the Netherlands starts on the 17th August 2015, check our Blog for news on that. In the meantime please keep on following the capacity building project in Vietnam.

Morrison van der Linden (student)

Martijn Manders (Head of the Maritime Programme)

Vietnam maritime archaeology project: Day 4-5, to Bai Lang and beyond

While the first 3 days were spent practicing our diving skills and getting comfortable in the water, Day 4 and 5 marked the beginning of our scientific approach to maritime archaeology. This is a process that will be developed and perfected over the coming weeks to make our work better, easier, and hopefully create a new generation of (Vietnamese) maritime archaeologists.

The first dives were performed at Bai Lang, where our main wreck site is. As mentioned before, Bai Lang is a beautiful, historic bay on the main island and this is where we attempted to set up our first research area. These “research areas” consist out of squares marked by buoys and GPS coordinates and are mainly used for surveys. Setting up these areas helps us in marking which regions we have already surveyed as to avoid redundancy. However, the beauty of the bay means that many tourists in speedboats visit the region, creating a safety hazard for our divers. It was therefore decided that we would continue to work in Bai Lang at a later stage and for now go to a nearby bay just around the corner. As this area had no name (or we just didn’t know its name) it was spontaneously dubbed “around the corner of Bai Lang bay”.

Setting up a research area with the GPS
Setting up a research area with the GPS
“Around the corner of Bai Lang bay” much resembles a less touristic version of Bai Lang bay. This does also mean that it is likely that there is less evidence of human activity in this area. However, the presence of a small, ancient temple along with pillboxes from the Vietnam war indicates that there is still plenty of (maritime)archaeology to be found here. An added bonus is that the island is also a military base which increases the likelihood that any possible archaeology has not been plundered yet.

An important part in setting up an underwater survey is setting up the baseline. This makes redundancy less likely and stops people from getting lost underwater. Furthermore, a measuring-tape is laid out so people know where they left off in their previous dive and thus know where to start on their next dive. This proved to be a tricky undertaking as many people, experienced as they are with diving, had little experience in using tools underwater or effectively tying water resistant knots. After we got most of the basic requirements out of the way it was time to start the first circular surveys. These initial circular surveys yielded some interesting results. A set of circular ballast stones was found and this at least proves that we are searching in the right area.

Setting up the baseline
Setting up the baseline
A circular ballast stone
A circular ballast stone
Another important process that we started at the end of this week was the GPS mapping of the bay. By taking coordinates of certain points along the bay, alongside a rough sketch, it becomes easier to keep track of where certain objects are found so we can find them again in the future. As this can be done from the surface, this was mostly done by divers who were on their surface interval to increase our efficiency.

One of the divers mapping the bay
One of the divers mapping the bay
After a week of mostly training and getting used to the circumstances these final 2 days showed great promise and created a perfect starting point for us to fully kick-start the project next week. Hopefully this means that the discovery of many interesting sites will follow!

Greetings from Hoi-An,

Mike

Day 10: The West Site Story

Today we completed 16 dives. We have finished drawing, measuring and filming the western part of the site and have now started on the eastern part of the site OVM10. On the western part of the site we have found a lot of different ship parts. For instance, the stern and the keel. Piece by piece the overall picture of the ship is emerging.

Although the site is harder to interpret with all the scattered fragments of the ship, the photogrammetry process is going a lot faster because of the coded targets we applied. It is much easier to align the different chunks of stills from the videos and this makes it easier to see what has been properly filmed. The photogrammetry experts are then able to tell the divers which parts still need to be filmed to give us a complete picture of the site.

Part of the site that we have processed in Photoscan
Part of the site that we have processed in Photoscan

We took some dendro samples yesterday and today we prepared them for analysis. This requires measuring each individual piece, recording and labelling. We truly hope the samples will be good enough for dating, since many of them do have wide year rings. The samples that were taken may have come from production forests. These forests produced specific trees for the shipbuilding industry from the late 17th century onwards. This is however, problematic for us as it is harder to date the wood using  dendrochronology. We’ll know more when the analysis is done.

Preparing the dendro samples for analysis
Preparing the dendro samples for analysis

Diving will continue this weekend and the pack-up will commence on Monday. The field school is wrapping up and some of the crew are leaving this evening.

Robert de Hoop (intern Maritime Programme)
Bronwyn Hughes (Leiden University)

Day 9: The condition of the OVM 10

We have found a lot of burned wood on the OVM 10. This might be the reason for sinking, but maybe it happened only after the ship was deserted. We will probably never know. The structure however must have burned for quite a while, based on the severity of the burning marks on the individual timbers.

The ship parts emerging from the sediment are quite degraded by Teredo navalis or shipworm. The timbers became exposed after the sand extraction for the Maasvlakte 1, but also other activities in the lake. Some structural elements on OVM 10 only became exposed recently due to illegal airlifting. This wood still hasn’t been attacked by the shipworm but is obviously very vulnerable for future attack.

An example of the burned wood that we found
An example of the burned wood that we found

The site has been particularly difficult to research, because it is not structurally intact and pieces of the ship are strewn about the lake floor. A hypothesis was suggested that this did not occur at or around the time of the ship’s sinking but could be a result of the dredging that took place. This could explain why so many of the planks and beams are sticking up out of the sand. The fact that beams and planks are also cracked and splintered at the ends, supports this theory.

Diver getting ready
Diver getting ready

The sandy bottom has also been a challenge to our divers who have to be careful not to kick up the sediment when taking measurements as this can decrease visibility. In general, visibility has been reasonable, around 3 meters. This is good enough for our photogrammetry recording.

Good visibility today
Good visibility today

Today divers took some dendro samples from different parts of the ship. These will be taken away for analysis to determine the age of the wood and where the tree was felled. Analysis will also be done to show the effect the shipworm has had on the wood as well as the bacteriological decay.

Degradation of the wood by the shipworm
Degradation of the wood by the shipworm

Most of the measurements have been taken and entered into Site Recorder and the picture of where each and every detected structure element is positioned is becoming clearer every day. The work the divers have been doing is very accurate and we are happy with the results so far.

Tomorrow some of the team members will be leaving us, so they will be wrapping up their work assignments of the project and saying their farewells.

Robert de Hoop (intern Maritime Program)

Bronwyn Hughes (Leiden University)

Hoi-An fieldschool day 3: Cham marine park diving session

Today marked a big step for this year’s Vietnam maritime archaeology project, namely: the first (archaeological) dives and surveys. After spending the first 2 days getting acclimatised and testing the diving skills of all the participants, the time had finally come to head out to open sea.

The main diving sites for this project will be near the Vietnamese island group of Cu Lao Cham, also known as the Cham islands. The Cham islands are located just east off the coast of the city of Hoi-An and the whole area is a protected UNESCO biosphere reserve. The main and only inhabited island of the Cham islands is Hon Lao and this island will therefore be the main focus of the project at this stage.

Blog 2 Vietnam 02

The geological layout of the bay of Hon Lao, in which the island its main harbour is situated, creates a “death-trap” for ships anchored there during a typhoon and heavy winds. This means that suddenly changing tides and weather conditions can cause large numbers of ships to sink here, especially during the historical period. These ships often contain a plethora of information regarding the different foreign trading parties that would visit the Cham islands. It is up to us to retrieve the information that sank along with these ships.

Blog 2 Vietnam 03

At approximately 10:00 AM the first team of divers exited the ship to test the waters and start the first archaeological survey of this year’s project. The main approach that will be used for surveying during this project is the swim-line search. Which is basically a team of divers that are spread out alongside a rope, surveying a large area at the same time. This technique was not used today however due to the it being the first day and therefore the different diving teams still need to grow accustomed to each-other.

Blog 2 Vietnam 04

Instead of using the swim-line search, today’s dives consisted mainly out of a free swim survey which, while not the most efficient technique, also came up with a number of results. The most noteworthy of which was a large anchor found in relatively shallow water (>6 meter). While these  finds are not necessarily always what you are looking for, they can serve as base or starting points for future surveys and it is therefore important to document the coordinates/exact location of where they are found.

Blog 2 Vietnam 01

Whilst the more experienced divers were already out at sea conducting surveys, some of the PADI-trainees experienced their first open sea dive today, with the rest of the PADI –trainees following tomorrow. Once these trainees are done with their PADI courses by the end of this week they can join the rest of the group in conducting underwater-surveys and will hopefully be valuable assets for the project!

Once again, greetings from Hoi-An.

Mike de Booij

Pictures by: Ian Mccan and Wongsakorn Rahothan

Day 8: Triangulation and trilateration

Today was already the third day of our campaign on the OVM 10. The whole day we were drawing, measuring and filming. We also tested so called ‘coded targets’ which should make the photogrammetry a lot easier. More on this, see below.

Now that we are familiarized with the site and have an overall picture of what is down there we are able to start taking measurements. We do this by selecting datum points which allow us to work in a precise way. These points correspond to different features or locations of the site. The measurements are made by using a method called triangulation. Measurements are taken between three different points, they are recorded underwater and once the diver brings them up to the surface they are entered into a computer program called Site Recorder. Site Recorder immediately tells you if you measured correctly and what the margin of error is. With all of these measurements we gather we are then able to draw an ever more accurate site plan and they can be used alongside the photogrammetry software.

Entering the measurements in Site Recorder
Entering the measurements in Site Recorder

For the OVM 10 we are trying out coded targets. These coded targets are attached to wood and/or are placed between different objects on the site. The coded targets are necessary for this site as recognition points because the site is spread out over a large area, with frames and deck beams surfacing the seabed.Between areas of sediment there are few features to detect. After stills are taken from the GoPro footage, Photoscan software can detect the coded targets in these photos more easily and align them much faster.

Lots of activity on deck
Lots of activity on deck

Three days ago we started off with a rough sketch of the site. Already we have a much better understanding of what is left on the Oostvoornse lake bed. With the actual measurements of the ship elements and their spread, step by step we are geting a good idea of what is there and what the significance is of OVM 10. The filming underwater is harder to do than on OVM 12 because of the spread of the elements and the visibility that is less here. This is why – as a backup – we will also use the conventional methods to record the site with additional drawing.

A coded target that is placed on the site
A coded target that is placed on the site

A large spread, interesting features, lots of illegal excavation done and wood exposed recently. What can we say about the condition of the site? More about that tomorrow.

Robert de Hoop (intern Maritime Programme)

Day 7: Finding our way on the OVM 10 site

After a test dive yesterday, we have started the archaeological fieldwork on OVM 10 today. The first task for each diver was to orientate on the wrecksite. This is really important in order to be able to execute the next tasks that are essential for the archaeological significance assessment that we want to do.

The site itself is fairly large, with bits and pieces of wreck sticking out of a mound of sediment. Again, like OVM 12, this site was probably hit during sand abstraction for the first extension of the Rotterdam Harbour (Maasvlakte 1) after which the area has been avoided for further abstraction. 

As we said yesterday; we are diving with scuba equipment on the OVM10. We are doing this because the site OVM10 lies at about 20 – 25 meters deep, is spread out over a large area, with frames and deck beams surfacing the seabed (sometimes for several meters) and with a visibility of about max 2 meters. Scuba gives you more freedom moving around than surface supply equipment. With the 300 bar Aga sets we have enough air with us. With a nitrox (40%) mix we can stay down at the site for an hour if we don’t go deeper than 23 meters. So we have a lot more dive time than on the OVM12. After two hours surface interval we can go in for another dive.

Each morning we start with a briefing of what we will do that day. Everybody gets his or her assignment and the situation will be discussed with the help of a hi-resolution multibeam sonar image of the site, printed in A0. Striking is the difference between the current situation on the seabed and the multibeam that was made in 2014. Much more of the shipwreck and e.g. ancient rope are visible: clearly some airlifting has been done before we came to the site. A lot of lines, measuring bars and parts of airlifts, all of which we had also found on OVM 12, have been found. Pieces of ancient rope give evidence to the damage this airlifting must have caused on the site. In the long run the wreck parts may be more vulnerable for shipworm attack if the salinity is not decreased or if the site isn’t physically protected.

The briefing of this morning
The briefing of this morning

Unfortunately we do not know what objects have been taken from the site and we probably will never know…

Today we got one extra student, which makes a total of 5:

Morrisson
Morrisson

Morrison van der Linden
My name is Morrison van der Linden and I’m from the Netherlands. I’m currently in my second year of the Maritime Archaeology Program in Esbjerg, Denmark. Like Robert I also studied archaeology at Saxion University in Deventer. I’m interested in almost every aspect of maritime archaeology and hope to gain some more experience during this fieldschool.

Check back tomorrow for more news on the methodology of mapping the site besides the use of photogrammetry.

Robert de Hoop (intern Maritime Programme)