To aid in the specification of the location of archeological findings on the wreck a baseline along the length of the ship was set up from the tip of the bow till the mid of the stern. This baseline is marked with tags at every 5 meters showing the distance from the bow.
Also two sections are extra marked with two lines perpendicular to the baseline. This is done at the mid section of the ship to clearly mark the location of the findings at that place and this is also done at 70 meters to mark the location of the second mast. Later investigations show that the mast is probably located more toward the 60 m mark.
All archeological research is done by divers with scuba equipment. Also a compressor and a water pump are used to clean the wreck. Both act as a kind of vacuum cleaner under water but the technique is different. With the water pump water is used to create suction and with the compressor air is used to create the suction.
In this picture you see the airlift used in combination with the compressor on the quay. The compressor pushes compressed air in the large tube (see the connection at the upper right end in this picture). This tube is placed under an angle of about 75 degrees with the end where the compressed air enters near the bottom where the cleaning is required. This causes the compressed air to flow upward through the tube taking sand and small stones with it.
All activities under water are limited in duration to about 1 hour because of decompression limits.
The wreck was located in 1987 when a survey was done to locate the wreck of the Alphen. At that time the first sketches were made of the exact location of the wreck under water and of some parts of the ship. At that time the wreck was in rather good condition and almost free of debris.
In 1995 the archeological research was picked up again with help of volunteers. The condition of the wreck was much worse and a lot of debris was found on top of the wreck. Since then small scale archeological excavations are done. From 1998 till 2002 a group of American archeologists has participated in the research and has made several detailed drawings of the ship (see the gallery in the section about the wreck).
Since September 2001 the research is concentrated on the middle section of the ship where wooden decking is found. This is the section where the engine room is located with probably intact engines, boilers and other equipment that is normally found in an engine room. The deck is in rather good condition although it is partly damaged. It is supported by iron beams. Under the deck a thick layer of mud is found which is partly removed. But because of the debris and sand on the deck and the fact that this layer of debris is thicker on the portside (closer to the quay) than on the starboard side there is a risk that the debris will slide into the excavated area. This would endanger the divers that are working there so the first effort is to remove the debris in this area from the ship.
More to the aft of the ship excavations were done to find the remainders of the second mast of the ship. No remainders of the mast were found and based on recent investigations it is expected that the mast is located a bit more to the bow than where is sought. These excavations uncovered part of the wooden deck and on top of the deck lots of ceramic plates and bowls. This was probably part of the freight and packaged in wooden crates.
Pictures of this find were taken underwater and then everything was brought to the surface and properly conserved. For conservation and storage purposes Stimana has a shed next to the Maritime Museum.
During excavation lots of artifacts and large pieces of charcoal were found. The charcoal is probably from the Mediator and is used as fuel for the steam engines. Because the excavation was limited to the upper deck some of the artifacts were from a more recent date and probably thrown in the water from the quay by people that lived or worked there or from boats that were moored there. All archeologically valuable artifacts were conserved and labeled (for pictures see the picture gallery in this section). Till this day the excavation is done with help of volunteer divers mostly on Sunday morning.