Salvage Equipment Used
Aqua Exploration's main pieces of equipment consists of a 6 metre catamaran ski-boat named "Seaker" (used for survey, searching and recovery work), a 7.5 metre catamaran ski-boat named; "Blower", with a built in prop-wash (used for the removal of sand overburden on shallow water wreck sites), a magnetometer (used to search and locate wreck-sites), a six inch airlift and a hydraulic blower (used to remove sand on deep wreck sites), various metal detectors (the largest one can locate metals lying 2 metres under the sand), high and low pressure compressors.
This is one of the most important pieces of equipment to locate deep and shallow water wrecks, as well as wrecks lying on a rocky bottom or covered over by sand. The magnetometer can be used over any terrain, be it on land or at sea. This instrument comes in two parts. The one part is called a "fish", which is towed behind the boat, submerged in the water and it sends a magnetic pulse reading back to the unit on the boat. This unit translates the measured magnetic pulses either onto a digital screen or onto a graphic printout. The magnetometer locks onto the earth's magnetic field which can vary slowly. When passing over any ferrous metals like anchors, cannon, chain etc., the magnetic field changes drastically and in turn this will be translated onto the digital reading which is given in "gammas", as well as drawn onto the printout. The gamma reading will change from the constant zero with approximately two gamma sensitivity, to hundreds and thousands of gamma differences, depending on how much ferrous metals are present and how close you are to the site. The printout will deviate from the relatively straight line to one of zigzagging across the page.
When our group discovered the Johanna , we found it to be lying in 2 to 6 metres of water and mostly covered by sand. This shallow depth gave us a choice of two types of equipment to remove the sand; one being a centrifugal pump and the other a propeller wash (prop-wash). We started off with the pump, but found it to be too cumbersome to handle and impractical with the amount of times it would block up. We then bought a prop-wash outfit, which had to be towed out to site as it was under-powered and lost steerage as soon as the wind picked up.
In 1984, after the Johanna discovery, Aqua Exploration (consisting of Charles and Arnold "Mickey" Shapiro, Frederik "Erik" Lombard, Andre Hartman, Traill Witthuhn and Michael Keulemans) was formed and the search for the Milagros , Brederode and other wrecks continued. They set about designing a versatile vessel and prop-wash to suit all conditions and named the apparatus "Blower". The Blower is a 7.5 metre catamaran, now driven by twin 90-hp. outboard motors and has a marine V8 motor connected to an inboard - outboard Z-drive leg. A cowling is fitted over the propeller and to this a 90 degree elbow bend pipe (fiberglass construction) is attached. This is the actual blower section. In principal the 90 degree elbow bend, re-directs the propeller wash towards the ocean floor. The force of this column of water, can be regulated by opening or closing the throttle of the V8 engine. The engine can push a column of water down to a depth of approximately 10 metres, where-after it no longer works effectively. To hold our Blower in position, a four point mooring system has to be set up. To be able to shift the position of the Blower to open up a new hole in a new area, the stern ropes must be pulled in or let out. The slack on the front ropes must be taken up so that the Blower will be held facing the surf at all times. Aqua Exploration have worked on more than 10 sand covered sites with the Blower and are certainly the most experienced in this field in South Africa.
This unit comes in two main parts. The surface unit consists of a hydraulic oil tank, a hydraulic pump and a 15 hp. petrol engine. The under water unit consists of the hydraulic power pack which drives a 9 inch impeller. The impeller is built into a housing in the shape of a mushroom with its stem. The stem is a nine inch pipe which contains the impeller. The pipe is attached to the mushroom helmet, but is open at both ends. The power pack is attached to the outside of the mushroom helmet and connected to the impeller, which is inside the pipe on the inside of the mushroom helmet. There is a control lever on the power pack, which the diver can regulate as he pleases. The impeller sucks water in from all around the helmet on the outside of the pipe and pushes this flow of water out through the 9 inch pipe. It works on the same principle as the prop-wash. The underwater unit is connected to the surface unit by two rubber pipes, one being a high pressure hydraulic pipe and the other a return pipe for the hydraulic oil to the oil tank. We have used this unit with great success on our deep sites, of which one lies in 45 metres of water.
Six Inch Airlift:
These units work well on deep sites as it works on the principle of air expansion. The unit is made up of a six inch steel pipe nozzle with an inlet lever tap and a length of six inch re-enforced rubber or plastic pipe attached to it. An air compressor on the surface pumps air down to the nozzle by means of a hose-pipe which is attached to the lever tap on the nozzle. The amount of air bled into the six inch pipe is controlled by the diver by means of the lever tap. The air travels up the six inch pipe and as it gets closer to the surface, it expands more and more, causing the suction at the nozzle to get stronger and stronger. The nozzle has a safety grid built over the inlet so that large articles cannot be sucked in which will block the pipe. The exit end of the pipe can be tied off so that the sand can be directed and deposited in an area of your choice.
The airlift is one of the most popular pieces of equipment used in the commercial and salvage diving fields.
"Seaker" (6 metre catamaran ski-boat):
"Seaker" is a 6 metre Supercat ski-boat and is powered by twin 60 hp. outboard motors. It is rigged out with a Navman DGPS, Furuno echo sounder and an Elsec magnetometer, to do our search, survey and recovery work. Both "ski-boats" have one ton carrying capacities and have 100 kg. hand winches fitted for lifting goods off the bottom. Aqua Exploration has also done successful excavations to depths of 45 metres, using their hydraulic blower and six inch airlift for sand removal.
Charles Shapiro cc T/A "Aqua Exploration"
South African Historical Wreck Society
+27 (0) 82 086 5937