Aqua-Tech Diving Services Underwater Hull Cleaning, Inspection, Surveys and Repairs for Vessels

Aqua-Tech Diving Services, based in Durban, South Africa, offers a variety of different merchant shipping and civil services to the offshore industry. With experienced divers, we are able to offer timely solutions for your diving requirements and are available to attend to your requirements in all ports around South Africa.

Underwater hull cleaning and propeller polishing

With our sister company Divers Tech, we have expanded into northern Mozambique, Port of Nacala, where we have managed to gain exclusive permission to complete underwater hull cleaning and propeller polishing at outer anchorage.

We are also associated with many big firms in South Africa with regards to the surveying and maintenance of pipelines.

Hull cleaning services

Aqua-Tech Diving Services offers hull cleaning services to the offshore industry, which includes the cleaning of the flat bottom, sides, grids, sea chests and rudder. It is a known fact that every dollar spent on a hull clean and propeller polish saves the company $8 in fuel. Our expertise in this field runs to over 1,000 vessels of all different lengths and drafts.

We are specialised in a mixed gas system that allows our divers to continue with a hull clean where the vessel is drafting over 12m. For these services the fees are slightly higher but it has been known that this system is effective and efficient.

Propeller polishing

During a propeller clean, all growth is sanded off first and then the disc pads are changed for polishing pads. Thousands of dollars are lost annually due to the inefficiency of the propeller. This can be caused by many things, including marine growth and mechanical damage, which can result in:

• Increased drag resulting in increased torque
• Decreased thrust
• Increased load on propulsion plant at a given speed
• Increased fuel consumption

A smooth and properly polished propeller costs less to maintain, reduces fuel consumption by up to 10% and does not foul easily.

Testing for propeller roughness

The Rubert Gauge Roughness Comparator has six roughness finishes that can be graded A – new propeller finish, and F – rough surface finish. We strive for grade A finish.

In-water surveys for vessels

We offer a range of in-water surveys, including visual inspections, photographic surveys and CCTV surveys. Our experienced teams have the capability to handle every aspect of the underwater inspection process, producing detailed reports for a wide variety of purposes, including:

• Damage assessment
• Preparation for sale or purchase
• Assessment of anti-fouling paint systems
• General inspections of hulls, plating, welding, water intakes, propeller and rudder
• Assessment of general hull condition and/or damage for classification society approval to extend dry-dockings
• Preparation for dry-dockings

Class surveys can vary in detail and length depending on the requirements of the client. The degree of reporting depends on whether the survey is undertaken for specific months or for two or three years of a dry-docking extension period or instead of dry-docking.

Vessel inspection services

We offer the following vessel inspection services: visual with photo documentation, closed circuit TV and video, and crack detection and definition.

Ship repairs

Our ship repairs include kettle patches, crack arrests, blanking, sealing and cofferdams (small and large). The general underwater repair service includes the following:

• Blanking of seawater inlets or overboard discharges for in-board repair
• Sealing stern tube glands
• Replacement of wasted anodes (welded or bolted on)
• Repairing damage by underwater welding and patching or steel plate insert by means of cofferdam and crack arresting
• Taking rudder pintle and tail shaft measurements
• Non-destructive testing for plate thickness
• Cropping of damaged propeller blades

Pipeline, reservoir and harbour services

Our range of pipeline services includes pipeline installations, pipeline surveys, and pipeline maintenance and repairs. In addition, we assist the large corporate plants with their fire reservoirs and clean water reservoirs.

We are available to help in berth extensions as well as in general survey work and the repair of quayside and underwater structures.

Contaminated-water diving services

It is very important to take safety seriously when diving in contaminated waters. We are available to complete a safe dive in these types of waters as we have the correct equipment available for use.