The Marker Guardian S4000SMHS is a multi-purpose buoy that can be adapted to perform a range of tasks limited only by the costumers needs. The lowered center of mass assures extra stability providing better working conditions for maintenance operations and less turbulence for sensitive equipment. S4000HS has a large volume which allows it to be equipped with a considerable amount of batteries, and a large surface that can support the installation of solar panels. This energy can be then used to recharge UAV’s operating nearby or maintain surveillance operations of ports entries, feed water quality monitoring devices, etc.

Water quality monitoring devices can be easily installed and readings can be taken either dependent or independently. Probes will function accurately and reliably in fresh, salt or brackish water.

The MG S4000SMHS is fully built in composite, withstanding impacts, solar exposure, salt water and corrosion exemplary. Each section is laminated using UV-stabilized, isophthalic polyester resin reinforced with Kevlar* and glass fibers to obtain maximum durability, crash resistance and water impermeability. With thicknesses ranging from 10 up to 15mm this structure is rigid durable and reliable.

S4000HS and can be upgraded with up to 32 sensors, communication antennas, all protected inside the structure without loss of efficiency. Its’ simplified modular structure and electronics allows for easy upgradability and maintenance.  From low cost energy efficient sensors to high precision devices can be installed to meet specific client needs.

This Guardian can generate alerts and send them to mobile devices via Wi-Fi or Bluetooth. For monitoring of several devices radio frequency transmitter is used connecting many devices to 1 central server. This allows for a real time monitoring of multiple parameters, such as: dissolved oxygen, salinity, water level, temperature, pressure, position or live video.

The fully composite structure assures a rust free, low maintenance lifespan. No part of the structure requires painting at any stage of the product’s life span. The MG can be supplied in all I.A.L.A. colors.


Consult Specifications tab for detailed information.


Isophthalic NPG Polyester resin reinforced with Kevlar and glass fiber; 316-grade SS fixtures.

Mass (Kg | lb)

1837 | 4050

Volume (L | gal)

4377 | 1156,3

Reserve Buoyancy (Kg | lb)

3387 | 7467

Nominal Draft (mm | in)

1985 | 78

Draft, Maximum (mm | in)

1990 | 78

Nominal Freeboard (mm | in)

1510 | 60

Freeboard , Minimum (mm | in)

300,0 | 11,8

H max (mm | in)

7460 | 294

Focal Plane Height (mm | in)

3390 / 133,5

Total Float Volume (L | gal)

21132 | 5582

Maximun Mooring Load (Kg | lb)

1016 | 2240

Safe Working Load, 1pt (Kg | lb)

10000 | 22046

Submergence  (Kg/cm | lb/in)

1,7 | 3,7

Visual Area (mt2 | ft2) (no signs)

7,5 | 81

Water Area (mt2 | ft2)

16,7 | 180

Wall Thickness (mm | in)

10 | 0,39

Ballast (kg | lb)

847 | 1867

Height (mm | in)

7460 | 294

Width (mm | in)

4000 | 31,50

Available Colours

Yellow, Red, Green as per I.A.L.A. recommendations.

Product Life Expectancy (years)


Intellectual Property Trademarks

Water Guardian and Marker Guardian are a registered trademark of Composite Solutions, Lda..

Quality Assurance

ISO 9001:2008

Warranty (years)


Standard Equipment

Data logger with Bluetooth connectivity with upgradability up to 32 sensors

32Gb of data storage

LCD display

Adjustable measuring time intervals.

Optional Equipment

Temperature, humidity, wind & pressure Kit

Electrical conductivity, temperature & depth sensor Kit

Wi-Fi, VHF, Iridium, RF, GPRS, 3G & 4G


Dissolved Oxygen Kit

Wi-Fi, VHF, Iridium, RF, GPRS, 3G & 4G

Surveillance camera/motion sensor Kit

Solar Panels

Upgraded battery capacity

Status light