ISO 20650:2025

International
Standard
ISO 20650
First edition
Inland navigation vessels — Small
2025-05
floating working machines —
Requirements and test methods
Reference number
© ISO 2025
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ii
Contents Page
Foreword .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 General requirements . 3
4.1 General requirements .3
4.2 Strength .3
4.3 Stability .4
4.4 Residual safety clearance.4
4.5 Residual freeboard .4
4.6 Sinking resistance .4
4.7 Draught marks .4
4.8 Manoeuvring characteristics . .4
4.9 Driving noise of the small floating working machine .4
4.10 Alarm signal .4
4.11 Stability and strength of working equipment .5
5 Steering system . 5
5.1 General .5
5.2 Drive unit of the steering system . .5
5.3 Indicators and monitoring devices .5
5.4 Penetrations for the rudder stocks .5
6 Helm station . 6
6.1 General .6
6.2 Unobstructed view .6
6.3 Control, indicating and monitoring equipment .8
6.3.1 General requirements .8
6.3.2 Specific requirements concerning control and monitoring equipment of main
engines .8
6.4 Elevating helm stations .8
7 Engine rooms . 9
7.1 General .9
7.2 Fire protection .9
7.3 Heat detector .9
8 Requirements on engine design . 9
8.1 General .9
8.2 Safety equipment .9
8.3 Propulsion systems .9
8.4 Engine exhaust systems of internal combustion engines .10
8.5 Fuel tanks, pipes and accessories for liquid fuels or hydraulic oils.10
8.6 Tanks, pipes and accessories for LPG .10
8.6.1 General .10
8.6.2 Cylinders .11
8.6.3 Fuel system components .11
8.6.4 Installation .11
8.6.5 Installation of cylinders . 12
8.6.6 Gas pipes and hoses . 13
8.6.7 Electro installation.14
8.6.8 Gas detection .14
8.6.9 Forced ventilation . 15
8.7 Bilge pumping and draining systems . 15
8.8 Penetrations for the propeller shafts . 15
9 Electrical equipment and installations .15

iii
9.1 General . 15
9.2 Protection against access to hazardous parts, against solid foreign objects, against
ingress of water .16
9.3 Maximum permissible voltages . .16
9.4 Generators, engines and transformers .17
9.5 Accumulators (batteries) and their charging devices .17
9.6 Switchgears .19
9.6.1 Switchboards .19
9.6.2 Switches, protective devices .19
9.6.3 Placement of switchboards .19
9.7 Installation fittings .19
9.8 Cables, insulated cables and cable systems .19
9.9 Lighting installations . 20
9.10 Navigation lights . 20
9.11 Additional requirements for electronic installations . 20
10 Special provisions applicable to electric vessel propulsion motor .20
10.1 General . 20
10.2 Generators, transformers and switchgear for electric vessel propulsion .21
10.3 Electric propulsion engines for electric propulsion .21
10.4 Power electronics for electric vessel propulsion .21
10.5 Monitoring equipment . 22
10.6 Control, regulation and automatic power limitation . 22
10.7 Protection of the electric vessel propulsion . 22
11 Equipment .23
11.1 Lifebuoys and lifejackets . 23
11.2 Anchor equipment . 23
11.3 Portable fire extinguishers . . 23
11.4 Additional equipment . 23
12 Safety at workstations .24
12.1 General .24
12.2 Protection against falling .24
12.3 Access to workstations . 25
12.4 Exits and emergency exits. 26
12.5 Ladders, steps and similar devices . 26
12.6 Interior rooms . 26
12.7 Protection against noise and vibration . 26
13 Working gear .27
13.1 Accessory equipment .27
13.2 Mobile and temporary machinery/work equipment .27
13.3 Winches .27
13.4 Cranes .27
14 Fuel-fired heating equipment .28
15 Owner’s manual .29
15.1 Basics . 29
15.2 Range of use . 29
15.3 References to tests to be carried out during operation . 29
15.4 Cranes . 29
15.4.1 Cranes operating instructions . 29
15.4.2 Periodic inspection of cranes by an expert . 29
15.4.3 Regular checks of cranes by a competent person . 30
15.5 Electric propulsion. 30
16 Marking of small floating working machines (machine type plate) .30
17 Testing.30
17.1 General . 30
17.1.1 Range . 30

iv
17.1.2 Individual testing and type testing . 30
17.1.3 Specimen selection for type testing . 30
17.2 Basic tests .31
17.2.1 Visual inspection and measurement .31
17.2.2 Presentation of manufacturer's certificates.31
17.3 Strength .31
17.4 Stability .31
17.5 Safety against sinking .31
17.6 Manoeuvring characteristics . .31
17.7 Noise limit values .31
17.8 Cranes .32
17.9 Electrical propulsion .32
17.10 Stairs .32
17.11 Climbing devices .32
Annex A (normative) Proof of stability .33
Annex B (normative) Manoeuvrability .36
Annex C (normative) Safety requirements on stairs and ladders .37
Annex D (normative) Safety requirements for winches . 41
Bibliography .44

v
Foreword
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The procedures used to develop this document and those intended for its further maintenance are described
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This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology, Subcommittee
SC 7, Inland navigation vessels.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

vi
International Standard ISO 20650:2025(en)
Inland navigation vessels — Small floating working machines
— Requirements and test methods
1 Scope
This document is applicable to small floating working machines used for work in, over, or on, inland waters.
This document specifies safety-related requirements and test methods.
This document specifies minimum requirements for small floating working machines with a length of < 10 m
and a product of length, width and depth of less than 30 m , with temporarily or permanently installed work
equipment or machines used on inland waters.
These small floating working machines can be used for activities such as extraction work, lifting work,
sampling, mowing and clearing work or comparable tasks.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 1035-1, Hot-rolled steel bars — Part 1: Dimensions of round bars
ISO 1035-2, Hot-rolled steel bars — Part 2: Dimensions of square bars
ISO 1035-3, Hot-rolled steel bars — Part 3: Dimensions of flat bars
ISO 2922, Acoustics — Measurement of airborne sound emitted by vessels on inland waterways and harbours
ISO 2923, Acoustics — Measurement of noise on board vessels
ISO 4254-1, Agricultural machinery — Safety — Part 1: General requirements
ISO 7010, Graphical symbols — Safety colours and safety signs — Registered safety signs
ISO 7165, Fire fighting — Portable fire extinguishers — Performance and construction
ISO 9519, Ships and marine technology — Single rungs and rungs for dog-step ladders
ISO 10240, Small craft — Owner’s manual
ISO 11102-1, Reciprocating internal combustion engines — Handle starting equipment — Part 1: Safety
requirements and tests
ISO 11105, Small craft — Ventilation of petrol engine and/or petrol tank compartments
ISO 12100, Safety of machinery — General principles for design — Risk assessment and risk reduction
ISO 12402-2, Personal flotation devices — Part 2: Lifejackets, performance level 275 — Safety requirements
ISO 12402-3, Personal flotation devices — Part 3: Lifejackets, performance level 150 — Safety requirements
ISO 13297, Small craft — Electrical systems — Alternating and direct current installations
ISO 13857, Safety of machinery — Safety distances to prevent hazard zones being reached by upper and lower limbs

ISO 14895, Small craft — Liquid-fuelled galley stoves and heating appliances
ISO 16180, Small craft — Navigation lights — Installation, placement and visibility
ISO 17631:2022, Ships and marine technology — Shipboard plans for fire control, damage control, life-saving
appliances and means of escape
ISO 18422, Ships and marine technology — Inland navigation vessels — Plate with instructions for rescue,
resuscitation and first aid for drowning persons
IEC 60092-504, Electrical installations in ships — Part 504: Automation, control and instrumentation
IEC 60364-5-54, Low-voltage electrical installations — Part 5-54: Selection and erection of electrical equipment
— Earthing arrangements and protective conductors
IEC 60529, Degrees of protection provided by enclosures (IP Code)
IEC 61000-4-2, Electromagnetic compatibility (EMC) — Part 4-2: Testing and measurement techniques —
Electrostatic discharge immunity test
IEC 61000-4-3, Electromagnetic compatibility (EMC) — Part 4-3: Testing and measurement techniques —
Radiated, radio-frequency, electromagnetic field immunity test
IEC 61000-4-4, Electromagnetic compatibility (EMC) — Part 4-4: Testing and measurement techniques —
Electrical fast transient/burst immunity test
IEC 62619, Secondary cells and batteries containing alkaline or other non-acid electrolytes — Safety
requirements for secondary lithium cells and batteries, for use in industrial applications
IEC 62620, Secondary cells and batteries containing alkaline or other non-acid electrolytes — Secondary lithium
cells and batteries for use in industrial applications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
small floating working machine
watercraft used on inland waters with a hull whose length is less than 10 m and whose product of length,
width and depth of less than 30 m , with temporarily or permanently installed working equipment or
machinery
EXAMPLE Mowing boats, watercraft for sampling, extraction work, keeping waters clean, lifting work.
3.2
residual safety clearance
shortest vertical distance between surface of the water and the lowest part of the small floating working machine
(3.1) beyond which it is no longer watertight, taking into account trim and heel resulting from the moments
3.3
residual freeboard
smallest vertical distance between the surface of the water and the upper surface of the deck at its edge
taking into account trim and heel
3.4
working area
area of inland water, where the work is carried out

3.5
operating range
driving range from the berth to the working area (3.4), and from/to the working area itself
3.6
propulsion system
system consisting of internal combustion engine and/or electric drive engine with power source including
power electronics, gearbox, shaft, propeller, etc., used to move the craft in the water
3.7
propulsion
diesel, LPG (liquified petroleum gas), electric or diesel or gas-electric propulsion system (3.6) of a small
floating working machine (3.1) containing at least one propulsion engine (3.9)
3.8
main propulsion
propulsion (3.7) used to achieve the manoeuvring characteristics
3.9
propulsion engine
engine for driving the propeller shaft or the shaft of comparable drive systems such as water jet drives
3.10
expert
person recognised by the competent authority or by an authorised institution, having specialist knowledge
in the relevant area on the basis of his or her professional training and experience, fully conversant with
the relevant rules and regulations and the generally accepted technical rules (e.g. ISO standards, relevant
regulations, technical rules), and able to examine and give a thorough and knowledgeable assessment of the
relevant systems and equipment
3.11
competent person
person who has acquired sufficient knowledge in the relevant area on the basis of his or her professional
training and experience and is sufficiently conversant with the relevant rules and regulations and the
generally accepted technical rules (such as ISO standards, relevant regulations, technical rules) to be able to
assess the operational safety of the relevant systems and equipment
4 General requirements
4.1 General requirements
Small floating working machines shall be built in accordance with the manufacturer’s specification.
At least one watertight collision bulkhead and one machinery space bulkhead shall be fitted up to the deck
or to the upper edge of the ship’s side. The collision bulkhead shall be installed at an appropriate distance
from the bow so that when the watertight compartment forward of the collision bulkhead is flooded, the
buoyancy of the fully loaded vessel is maintained and a residual safety clearance of not less than 300 mm is
maintained.
4.2 Strength
The strength of small floating machines shall be sufficient to withstand the stresses to which they are
exposed, under the conditions of use specified by the manufacturer.
When using steel S 235 B according to ISO 630-2, the requirement above is fulfilled if the thickness of
the bottom and side plates is at least 3 mm. If other materials or lower material thicknesses are used, a
mathematical verification is required.

4.3 Stability
The stability of small floating machines shall withstand the stresses to which they are exposed, under the
conditions of use specified by the manufacturer.
The stability of a small floating machinery shall be sufficient for the loads to which it is subjected, under
the conditions of use specified by the manufacturer. It shall be demonstrated mathematically by the test
conditions given in Annex A.
For small floating working machines where no change in heel or trim can be caused by their working
equipment and where a shift in the centre of gravity can be ruled out as far as possible, a mathematical
verification may be dispensed with.
4.4 Residual safety clearance
The residual safety clearance shall be at least 300 mm.
4.5 Residual freeboard
The residual freeboard shall be at least 300 mm.
4.6 Sinking resistance
Small floating working machines shall be safe against sinking in the event of flooding of one watertight
compartment.
The residual buoyancy force at the end of flooding of any compartment of the small floating working machine
shall be at least 100 N for each designated crew member.
4.7 Draught marks
The plane of maximum draught shall be marked on each side at each end of the small floating working
machine by indelible draught marks in a contrasting colour. These shall consist of a rectangle measuring
150 mm × 30 mm (L × H), with the base line horizontal and coinciding with the plane of the maximum
allowed draught.
4.8 Manoeuvring characteristics
Small floating working machines shall:
— have adequate driving and manoeuvring characteristics in accordance with Annex B;
— be able to reach a minimum speed of 4 km/h in relation to the water in the travel range.
4.9 Driving noise of the small floating working machine
The noise emitted by a small floating working machine under way at a lateral distance of 25 m from the
craft’s side shall not exceed 75 dB(A) measured in accordance with ISO 2922.
4.10 Alarm signal
There shall be an alarm signal that can warn all persons on board in case of general emergency.
The alarm signal shall be clearly distinguishable from other signals. It shall produce a sound pressure level
at all workstations that is at least 5 dB(A) higher than the maximum local sound pressure level.

4.11 Stability and strength of working equipment
The stability and strength of working equipment and, where appropriate, its attachments, shall be sufficient
to withstand the forces resulting from the expected heel, trim and movement of the floating equipment.
5 Steering system
5.1 General
Small floating working machines shall be fitted with a reliable steering system which provides at least the
manoeuvrability required by Annex B.
The steering systems shall be designed in such a way that the rudder cannot change position unintentionally.
The steering system as a whole shall be designed for permanent lists of up to 15° and ambient temperatures
from ‒20 °C to +50 °C.
The components of the steering system shall be robust enough to always to withstand the stresses to which
they can be subjected during normal operation.
5.2 Drive unit of the steering system
The steering system shall incorporate a manual drive or a powered drive unit if so required by the forces
needed to actuate the rudder.
Regardless of rudder position, a kick-back of the steering wheel shall be prevented when the manual drive is
engaged.
A steering apparatus with a powered drive unit shall be protected against overloads by means of a system
that restricts the torque applied by the drive unit.
Hydraulic steering apparatus drive units shall have:
— an emergency mode such as manual operation;
— a level alarm for the hydraulic tank;
— the pipework designed, dimensioned and arranged in such a manner to exclude, as far as possible,
mechanical damage or damage resulting from fire.
5.3 Indicators and monitoring devices
The rudder position shall be clearly displayed at the steering position. If the rudder-position indicator is
electric it shall have its own power supply.
An optical and acoustic alarm shall be present at the steering position to signal:
— the oil level of the hydraulic tanks falling under the lowest content level;
— failure of the electrical supply for the steering control.
5.4 Penetrations for the rudder stocks
The penetrations for the rudder stocks shall be designed to prevent the spread of water polluting lubricants.

6 Helm station
6.1 General
Helm stations shall be arranged in such a way that the operator may at all times perform his or her task
while the vessel is under way.
In driving mode, sound pressure generated by the vessel and measured at the level of the operator’s head at
the steering position shall not exceed 70 dB(A).
The operator’s workstation shall be equipped with technical protection against UV radiation and
precipitation which is sufficient for the expected demand.
6.2 Unobstructed view
There shall be an adequately unobstructed view in all directions from the helm position for safe operation.
The equipment shall be under visual control in all positions from the helm position to the water surface.
The upper edge of the forward-facing windows of the helm station shall be high enough to allow a person at
the helm station (at eye level, which is 1 324 mm for a seated person and 1 800 mm for a standing person,
both above the floor) a clear forward view (to the horizon and an angle of 10° upwards) of at least 120°
within the forward semicircle. At the rear, a field of vision of at least 30° shall be possible.
For an example of the design of the unobstructed view, see Figure 1.
Clear vision through these windows shall be ensured in all weather conditions.
Windowpanes used in the helm station shall have a minimum light transmission of 75 %. If they are made of
glass, safety glass shall be used. To avoid reflections, the helm station front windows shall be glare-free or
fitted to exclude reflections effectively.

Key
1 midpoint of the visual axis
2 mid of small floating equipment, the field of view ahead
3 plane of shoulder
4 frame of the helm station
A ≥ 30°
A + C + E ≥ 60°
B, D ≤ 6°
A + C + E + G + J ≥ 120°
Figure 1 — Example of the unobstructed view

6.3 Control, indicating and monitoring equipment
6.3.1 General requirements
Control equipment needed to operate the small floating working machine and its working equipment shall
be brought into its operating position easily. That position shall be unambiguously clear.
Monitoring instruments shall be easily legible. Light sources shall be neither intrusive nor impair the
legibility of the monitoring.
There shall be a system for testing the warning and indicating lights.
It shall be possible to clearly establish whether a system is in operation. If its functioning is indicated by
means of an indicating light, this shall be green.
Any malfunctioning or failure of systems that require monitoring shall be indicated by means of red
warning lights.
An audible warning shall sound while a red warning light lights up. Audible warnings may be given by a
single, collective signal. The sound pressure level of that signal shall exceed the maximum sound pressure
lev
...