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Rooswijk1740 Support Project 2018: investigation of cannons nearby Rooswijk

In the summer of 2018, a team of divers headed towards the waters of England.  Their objective: investigate whether the nearby cannon site related to the wreck of the Rooswijk.  Read their planning and report. 


Monday 6 August 2018
• Divers arrive in Ramsgate in the afternoon
• Divers prepare diving and measuring equipment

Tuesday 7 August 2018
• One or two dives
• Dive log and report on findings

Wednesday 8 August 2018
• One or two dives
• Dive log and report on findings

Thursday 9 August 2018
• One or two dives
• Dive log and report on findings

Friday 10 August 2018
• Pack up equipment and conclude project
• Free to leave from nine thirty


  • Project leader: Mark Beattie-Edwards MA MCIfA, Chief Executive Officer of the Nautical Archaeology Society.
  • Members: 3 Dutch sport divers and 4 English sport divers
  • Team 1 Rob and John van N
  • Team 2 Monica and Deborah (‘Debby’)
  • Team 3 Nick, John and Duncan
  • Skipper of the Peganina: Anthony Hills


We all assembled at 16.00 hours on Monday 6 August 2018 at the Old Port Workshop in Ramsgate. This building is also in use as a storage location for the objects found during the recovery of the Rooswijk.

After extending a warm welcome to everyone present, project leader Mark began his briefing. The aim of the project is to investigate whether the nearby cannon site is related to the wreck of the Rooswijk.

On the basis of last year’s study results, a situation drawing (figure 1) was made of the cannon site.

Figure 1

A comparison of this situation drawing with a new multibeam survey carried out in the spring of 2018 (figure 2) revealed a number of notable differences:

  1. To the north of cannon 6 (at a distance of approximately 4 metres), another possible cannon was revealed on the multibeam.
  2. The orientation of cannon 5 and cannon 10 are not the same on the multibeam as in the situation drawing.

On the basis of this new information, the tasks were determined for the first dive:

First dive (short slack):

  • Team 1: will install the shotline. The skipper will attempt to position the shotline as close as possible to cannon 1&2 (see figure 1) while Rob and I will shift the anchor to cannon 1&2, and fix it in position, on the basis of the actual location. A ring of floats will then be sent up to inform the other teams that the shotline is in position and that it is safe to dive. If there is sufficient time left, we will investigate whether there are still lines in position to cannon 9 and cannon 10.
  • Team 2 will investigate whether the line to cannon 9 is still present. If present, they will continue swimming towards F-403 which is probably a wooden object that was part of a ship, or possibly a chest.
  • Team 3 will position a line via cannon 1&2 towards cannon 5 to determine whether a new cannon has now emerged, or whether the drawing as made was incorrect.

Second dive: (long slack):

Depending on the results of dive 1, it is possible that only the shotline will be positioned in dive 1.

  • Team 1 will check (or replace) the lines towards cannon 9 and 6
  • Team 2 will check (or replace) the lines towards F-403
  • Team 3: will install a line towards cannon 5

Tuesday 7 August

At around 4 a.m. we got up and after breakfast (happily not a full English) we headed to the Ramsgate yacht marina. After loading up our diving gear we set out on the Peganina towards the cannon site. During the passage we saw the sun rise, and the sea was fortunately relatively calm.

We soon arrived at the cannon site and in the distance we could see the DSV Curtis Marshall, the diving vessel responsible for the recovery of the Rooswijk. The skipper placed the Peganina above the suspected location of cannon 1&2 and dropped the shotline anchor.

At around 6 a.m., the divers prepared to enter the water. Just before the start of the short slack, Rob and I (team 1) were dropped off by the buoy, and descended. At a depth of 24 metres we reached the bottom and were immediately able to feel that we were close to a cannon. After cleaning the tag, we saw that it was cannon 3 (see figure 1), which is situated just short of cannon 1&2. We moved the anchor block across cannon 3 and fixed it to cannon 1. We still had a little time left to inspect cannon 1 and discovered the lines towards cannon 10 and cannon 9. Moving on, we followed the line towards cannon 9 to see whether it was still intact. After a short swim, we discovered that the line had been covered by sand. We would have had to excavate around 40 cm of sand to reveal the line. Further attempts at excavating the line proved impossible, and we decided to go back to the shotline and return to the surface. While ascending, we met the other teams.

Team 2 also discovered that the line to cannon 9 was buried under the sand and then installed a temporary line towards cannon 9, and concluded their dive.

Team 3 went in search of cannon 5 to investigate its position. However, they were unable to determine how it was lying.

Once everyone had changed, we headed to the DSV Curtis Marshall to record our observations on the relevant forms. During a sandwich lunch, we received an explanation by Martijn Manders (project leader) about the recovery of the Rooswijk and how the Rooswijk is believed to have sunk. Because the professional divers were preparing for their dive during the long slack, we left them to it and returned to the Peganina.

The teams preparing for their second dive.

Planning for dive 2. On the basis of the results of dive 1, following their descent, team 1 will as quickly as possible go in search of cannon 9 to locate the line to cannon 6. Team 2 will replace the temporary line to cannon 9 with a permanent line and will then install a line towards F-403. Team 3 will once again go in search of cannon 5, to examine the local situation.

Results of dive 2:

Team 1 followed the temporary line towards cannon 9 and then went in search of the line towards cannon 6. A line was discovered which was freed up during the dive. At the end of the line, the object turned out to be the F-403. Team 1 swam back to cannon 9 to go in search of the line towards cannon 6. This line was rediscovered, but there was not sufficient time to clear the line and so we returned to the shotline for the ascent to the surface.

Team 2 installed a permanent line from cannon 1 to cannon 9 and via the previously uncovered line, continued towards F-403, where they made a drawing of the object.

Team 3 continued its search for cannon 5 but due to the absence of lines they were not able to find cannon 5.

When everyone was back on board, we returned to port and went back to the workshop, to process the results on the relevant forms.

Following the debriefing, we returned to our accommodation for a meal and an early night.

Wednesday 8 August 


We decided to skip the short slack, and concentrate on a single long dive. During the briefing, we were set the same tasks as yesterday’s dive 2.

On arrival in the port of Ramsgate, we saw that the DSV Curtis Marshall had returned to shore due to higher winds, making it no longer safe to dive. Because our vessel is considerably smaller and not attached by four anchors, we decided to determine whether it was safe for us to dive.

When we arrived at the cannon site, it turned out to also be unsafe for us to dive, and we returned to port. After eating lunch in the port, we headed for Ramsgate maritime museum to measure a cannon and two anchors retrieved as part of the Big Cannon project* and the Big Anchor project. After an explanation by Mark, under Nick’s supervision, we measured the objects. We then visited the rest of Ramsgate maritime museum where another Dutch cannon was on display, in the attic room.

Thursday 9 August 

The planning was the same as for Wednesday.

Weather conditions were even worse than on Wednesday. We were informed by Martijn that he too would be remaining in port all day and would spend the time transferring the retrieved objects from the DSV Curtis Marshall to the Old Port workshop.

We made one attempt to reach the cannon site on board the Peganina, but this quickly proved impossible. We returned to port, and returned our diving gear to the workshop.

At the workshop we examined the objects retrieved from the Rooswijk and Martijn and Robert explained a number of the retrieved objects and gave us the opportunity to take photographs.

At the end of the session, we made one group photograph (see above); part of the team went home and the rest returned to the team accommodation.

Friday 10 August 

We tidied away the team accommodation and everyone headed for home.

Rob Konings
John van Nieuwenhuizen

With thanks to:

  • Rijksdienst voor het Cultureel Erfgoed
  • Nautical Archaeology Society
  • Historic England

* The aim of the Big Cannon/Anchor Project is to use the power of Facebook to record historic cannon and maritime heritage. Cannon are not only important historical artefacts that must be recorded; they also tell stories of the past that need to be told.