The first Green Antifouling system

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The next innovation is here: TAKE CARE of your boat hull with a system completely green and efficient.

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KeelCrab is an italian company promoting for 10 years a new paradigm: underwater hull maintenance with innovative products, taking care of the marine environment.

Check all the products features composing the first antifouling kit completely green and biocide-free.


Keelcrab Paint is our catalogue of hull chemicals recommended in which you will find new-generation biocide-free antifoulings.


Ultrasonic antifouling is a high-frequency total green ultrasonic emitter. It prevents the formation of fouling  on the hull and metal parts of your boat.


Unique system able to clean in water to maintain hull cleaned and antifouling efficient. Moreover ypu can use it for for site survey: record the cleaning activity through WIFI HD directly to your smartphone: share the record or invite people to follow live the operation.

Keelcrab Paint

Water-repellant antifouling

In order to deal with the increasing stringent (global) regulations on the use of biocides  in anti-fouling paints, we started a collaboration with an italian company who provides ahydrophobic, non-water-soluble and 100% environmentally friendly chemical characteristics that espouse the ‘replace biocide with drone’ philosophy in order to maintain top performance and reduce the amount of fuel needed and the associated CO2 emissions into the atmosphere.


The most important guidelines

It is a transparent antifouling for the protection of hulls and tubulars that does not contain zinc, copper or biocides. its high water repellency drastically slows down the biofouling process and simplifies cleaning.

it is not a coloured paint because its composition is waxy and makes the hull water-repellent and less susceptible to water friction. 

Calculate the square metres paintable surface: X multiplied Y where X is the Estimated hull surface area and Y is the correction coefficient:

  • It simplifies the removal of algae or dog teeth;
  • It is easy to apply by spray;
  • It reduces costs and labour time and dries in just two hours;
  • It is environmentally friendly and does not release zinc and copper into the environment;
  • Allows the hull to glide through the water with less friction.

Aqua Ward FM 41 is also suitable for use on finished surfaces such as outboard engines, trim tabs, rudder blades and is suitable for all types of hull.

  • Price: 60 Euro per litre
  • Colour: transparent
  • Yield: 6/8 square metres per litre
  • Recommended coats: 2
  • Application: roller/spray (airless)
  • Dry layer: 40/50 microns
  • Wet layer: 70/90 micron
  • Substrate preparation: normal epoxy primer – two-component
  • Applicability on axles, propellers and rudders: not recommended.
  • Formats: 1L, 5L. 20L. 500 ml spray, 60 L.

Ultrasonic antifouling

Prevent biofouling

What makes this ultrasonic antifouling unique is the total absence of inconvenient and onerous on-board probe wiring and gluing (done by contracted technicians). Ultracrab comes with a handy floating buoy that makes it unique and quick to install, executable in no time by anyone.

Alternating sound pulses (cyclic sound compositions) of high frequency and variable power make this ultrasonic antifouling the first emitter capable of achieving perfect efficiency on both live work (of any material and related sea intakes) and metal components.

The constant propagation of these sound waves procures damage to vacuoles and cellular tissue, inhibiting cellular coupling and vital functions and thus the growth of algae or barnacles by registering immediate changes in the color, density and rooting of vegetation to surfaces, up to a total coverage of 20 meters in length of the vessel.

Questions about Ultracrab

Ultracrab is very simple to install. The supplied kit includes a floating buoy prepared for anchoring the ultrasonic sensor, easily hoisted by a pair of lines to the mooring dock (or directly to the stern or bow bollards of your boat). It will be very important to direct the sensor (by adjusting the support screws) toward the boat at a variable angle (between 5 and 45 degrees) looking as much as possible for wave propagation to the living work. Once installed, connect the power connector to the case/switch and supply power at 220/110volts.

Ultracrab is an excellent tool for maintaining the condition of the hull over time (especially during long stops of the boat in closed waters); to achieve maximum efficiency, it is strongly suggested that Ultracrab be installed in conjunction with the launch of your boat (with a clean hull and new antifouling).

Ultracrab is designed to keep your hull, including the metal parts, at maximum efficiency, and its continuous and constant action on the surfaces soothes proliferation and freezes the condition of the hull at any given time decreasing the amount of ordinary and extraordinary interventions in the long run, preserving and protecting your hull.

Ultrasonic waves have a total range of 20 meters in length by 6 meters maximum in width.

  • Power supply (factory settings): 115 VAC (93…. 132 VAC) or 230 VAC (186… 264 VAC)
  • Supply voltage frequency: 50 / 60 Hz
  • Power consumption: 60/130 W
  • Maximum range: up to 82 feet (25 metres)
  • Operating temperature range: -10° up to +70°
  • Operating basis: Multi-frequency (automatic)
  • Surge protection: yes
  • LED operation indicator: located in the control box
  • Electronic module protections: yes
  • Cable protections: yes
  • Environmental protection: IP56 (control box)
  • CE approval: EN 61000-6-1 (2007) & EN 61000-6-3 (2007) / A1 (2011)
  • UL approval: Power supply E183223 / E258355
  • Weight: 10.6 kg (complete set)

Underwater hull cleaner

Hull maintenance and Inspection

Characterized by a plastic exoskeleton with a neutral hydrostatic buoyancy, it maintains perfect adherence to the hull thanks to an important suction effect generated by a powerful marinised pump motor, removing and sucking up algae or vegetation that typically form on the living workings of boats during periods of docking in closed waters.

The robot’s movement is ensured by natural rubber or P.V.A. brushes driven by tracks that allow easy maneuvering in all directions, on any surface and making the drone adept at overcoming obstacles.

The high-resolution underwater camera allows the robot to be maneuvered by means of a wired remote control displaying the video stream on a 7-inch display, tablet or phone (optional) in high resolution.

FAQ about our underwater robots

Traditional methods offer comprehensive, manual cleaning operations, sometimes underwater or sometimes during hauling and launching activities. KeelCrab is a new method for the hull of recreational boats that aims to complement routine maintenance by reducing medium-term extraordinary interventions. For this reason, divers and shipyards integrate our system into their customer services.

Keelcrab is powered by a 20 m Kevlar cable and uses a plug suitable from 110 V to 220 V by the standard for marinas worldwide. We provide a standard socket for marinas around the world, as well as the option of requesting an inverter generator kit for remote use. The only alternative is to use an electric generator-solar panels currently cannot support the drone’s energy use.

We provide a nylon filter bag in several micrometer sizes (180 micron or 50 micron) to recover waste material, algae or vegetation produced by the cleaning operation.

Moreover our A.N.C.C.P certified brushes with different abrasive levels do not remove antifouling paint increasing its efficiency over time.

The robot cleans 95% of the hull surface: hull and rudder. Floating discs allow the drone to move vertically from hull to keel and rudder.


We provide Ultracrab in order to keep the propeller (even the stern feet) cleaned. It is an ultrasonic antifouling device easy to install at the stern: the constant propagation of high-frequency, variable-power sound pulses prevents algae formation.

You can use our  KeelCrab App available for IOS and Android Store: watch the hull inspection from the camera, record it, share the video content or invite people in live streaming.

Our regular service prevents the growth of barnacles. Our brushes are designed to remove algae vegetation. In case of principle of scaling and barnacle formation, we suggest our vertical motorized brush with stainless discs, an optional not included in Keelcrab PRO equipment that you can order in case of need.

Considering a 2.5 m²/min velocity, the drone cleans a 12 meters boat lenght (40 feet) in 1.5 hours, a 18 meters boat lenght (60 feet) in 2 hours, a 24 meters boat lenght (80 feet) in 3 hours.

We provide a remote control connected to the drone with 7″ display, joystick and 7-meter cable. You can also transmit the camera feed to your smartphone with the Wi-Fi Mobile Connectivity kit (standard on the Pro Pack).

Careful rinsing in fresh water after each use; after cleaning is completed, be sure to store the electronic box and remote control in a dry place.

We provide three different brushes for three different levels of cleaning: white soft nylon brush; yellow medium nylon brush; and stainless brush.

Before replacement, brushes last about 100 hours, longer if cleaning is done on regularly maintained boats and not on hard fouling.

You can manage standard maintenance for your own: we provide you a manual with tutorials to change brushes, wall grips, spare parts.

Underwater robot for cleaning and inspecting the hull of your boat or yacht up to 45 feet lenght.

Underwater robot for cleaning and inspecting the hull of your boat or yacht up to 65 feet lenght.

What our customers say

Everyone who joins our network deserves great attention from us.


Water-repellant antifouling

€ 55,00  per liter

Request a complete quotation or your ship


Ultrasonic antifouling device

€ 1986,00 

Available for ships up to 80 feet (25 meters) lenght


Keelcrab ONE + Ultracrab +10 liters Alvida FM41

€ 4686,00 

Available for ships up to 45 feet (15 meters) lenght


THE KeelCrab + Ultracrab + 15 liters Alvida FM41

€ 5986,00 

Available for ships up to 65 feet (20 meters) lenght


THE KeelCrab + accessories + Ultracrab+Alvida FM41

Request a quotation

Available for ships over 65 feet (20 meters) lenght


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